Comparing Corneal Variables in Healthy Subjects and Patients with Primary Open-Angle Glaucoma
|
|
- Jasmin Mason
- 5 years ago
- Views:
Transcription
1 Glaucoma Comparing Corneal Variables in Healthy Subjects and Patients with Primary Open-Angle Glaucoma Federico Saenz-Frances, 1 Julian Garcia-Feijó, 1 Luis Jañez, 2 Lara Borrego-Sanz, 1 Jose M. Martinez de la Casa, 1 Ana Fernandez-Vidal, 1 Carmen Mendez-Hernández, 1 Enrique Santos-Bueso, 1 Juan Reche-Frutos, 1 and Julian Garcia-Sánchez 1 From the 1 Department of Ophthalmology, Hospital Clínico San Carlos, and the 2 Instiuto de Tecnología del Conocimiento, Universidad Complutense de Madrid, Madrid, Spain. Supported in part by Instituto de Salud Carlos III Grant Red temática de Investigación Cooperativa. Proyecto RD07/0062: Patología ocular del envejecimiento, calidad visual y calidad de vida. Submitted for publication September 30, 2010; revised November 22 and December 13, 2010; accepted December 28, Disclosure: F. Saenz-Frances, None; J. Garcia-Feijó, None; L. Jañez, None; L. Borrego-Sanz, None; J.M. Martinez de la Casa, None; A. Fernandez-Vidal, None; C. Mendez-Hernández, None; E. Santos-Bueso, None; J. Reche-Frutos, None; J. Garcia-Sánchez, None Corresponding author: Federico Saenz-Frances, Department of Ophthalmology, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain 28040; federicosaenzfrancessb@gmail.com. PURPOSE. This study was designed to identify possible differences between healthy subjects and patients with primary open-angle glaucoma (POAG) in keratometry, central corneal thickness, overall corneal thickness, mean thickness of a circular zone centered at the corneal apex of 1-mm radius (zone I), and mean thickness of several concentric rings also centered at the apex of 1-mm width (zones II to VI, respectively). METHODS. These variables were recorded in 126 healthy subjects and 130 patients with POAG. Corneal thicknesses and the power of the flattest and steepest axes were compared between the two populations using a t-test and the position of the flattest axis using a Mann-Whitney U test. A binary logistic regression procedure was used to determine the diagnostic capacity of the corneal variables using the area under the receiver operator characteristic curve (AUC) to select the best regression equation. RESULTS. Significant differences between subjects and patients were detected in mean corneal thickness and in mean thicknesses of zones I to VI. The logistic regression model included as predictors the mean corneal thickness and the mean thicknesses of zones IV and VI; for this model, the AUC was 0.711, sensitivity was 67.7%, and specificity was 65.5%. CONCLUSIONS. Healthy subjects and glaucoma patients differ significantly in terms of mean overall corneal thickness and thicknesses of the corneal zones I to VI defined here. The variables mean corneal thickness and mean thicknesses of zones IV and VI are able to discriminate between subjects with or without glaucoma. (Invest Ophthalmol Vis Sci. 2011;52: ) DOI: /iovs Primary open-angle glaucoma (POAG) is defined as an optic neuropathy of multifactorial origin whose main characteristic feature is optic nerve disc damage caused by a loss of ganglion cells. 1 Elevated intraocular pressure (IOP) is the principal risk factor known for this disease to develop and progress. 2 6 Today s criterion standard for determining IOP is Goldmann applanation tonometry. However, it is precisely the limitations of this tonometry system, such as the dependence of its measurements on central corneal thickness (CCT), 2,3 that have determined, on one hand, the development of new tonometers that are less affected by corneal variables 7 10 and, on the other, a growing interest in corneal structure. Effectively, characterization of CCT has revealed its role both as a confounding factor when measuring IOP and as a risk factor for the development and progression of glaucoma The most widespread method used to determine CCT is ultrasound pachymetry, in which the examiner places a probe on the approximate center of the cornea. The Pentacam (Oculus, Lynwood, WA), based on the Scheimpflug principle, captures images of the cornea and, with keratometry, calculates corneal thickness across the entire corneal by taking perpendicular measurements to the surface every 1 m. It also has the added benefit of automatically locating the corneal apex This study was designed to identify differences between healthy subjects and patients with POAG in terms of the power of the flattest and steepest axes of the cornea, their position, and the thickness of several defined corneal zones, all determined using the Pentacam. MATERIALS AND METHODS We performed a cross-sectional study in 126 healthy volunteers and 130 patients with primary open-angle glaucoma. The patients were recruited from the Glaucoma Unit of the Hospital Clínico San Carlos in Madrid, Spain, and control subjects among the patients relatives and hospital staff. The study protocol was approved by our institution s review board and complied with the guidelines of the Declaration of Helsinki. Informed consent was obtained from each participant before inclusion in the study. All study participants were Caucasian. Eyes were considered to be glaucomatous if they had shown abnormal results in at least two consecutive visual field examinations (Octopus TOP-G1X; Interzeag, Geneva, Switzerland) and if there was evidence of glaucomatous damage, as determined by the appearance of the optic nerve head. Glaucoma patients were required to show gonioscopic evidence of an open angle. Subjects with nonprimary open-angle glaucoma (e.g., pseudoexfoliation, pigment dispersion, neovascularization) were excluded. Control subjects had to have an IOP 21 mm Hg, a normal visual field, and a nonglaucomatous-appearing optic disc. General exclusion criteria were spherical equivalent greater than 5 diopters, or 3 or more diopters of astigmatism, a best-corrected visual acuity lower than 20/25, opacities in the cornea or lens impairing optic nerve head visualization, and alterations in optic nerve head morphology, such as oblique discs or peripapillary atrophy. We also excluded subjects who had undergone previous eye surgery and those whose visual field defects were of causes other than glaucoma (e.g., demyelinating disease, nonglaucomatous neuropathy, or a central nervous system disorder). If both eyes of a patient or a subject fulfilled all the Investigative Ophthalmology & Visual Science, May 2011, Vol. 52, No. 6 Copyright 2011 The Association for Research in Vision and Ophthalmology, Inc. 3683
2 3684 Saenz-Frances et al. IOVS, May 2011, Vol. 52, No , , and ), CCT (determined by ultrasound pachymetry), mean overall corneal thickness, and mean corneal thicknesses in zones I, II, III, IV, V, and VI. To select the statistical test for comparisons, the normality of the quantitative data were assessed using the tests Shapiro-Wilk and Kolmogorov-Smirnov; the Student s t-test was used for quantitative data, and the Mann-Whitney U test was used for qualitative data (position of the flattest axis) and for any nonnormal distribution of data. To determine the capacity of the set of corneal variables selected to discriminate between control subjects and glaucoma patients and to establish the presence of interactions or confounding factors among the variables, a binary logistic regression model was constructed in which the dependent variable was the presence or absence of glaucoma, and the corneal factors examined were the independent variables. The area under the receiver operator characteristic (ROC) curve (AUC) was used as a measure of the best regression equation. FIGURE 1. Example of the information provided by the Pentacam. The box in the lower right-hand corner shows the corneal thickness map, which is accompanied in the right-hand column by a color-coded key to the corresponding thicknesses. inclusion and exclusion criteria, the left eye was selected (www. randomization.com). All the study participants underwent examination with an imaging device (Pentacam; Oculus, Lynwood, WA) and ultrasound pachymetry (Dicon P55; Paradigm Medical Industries Inc., Salt Lake City, UT). Given it is a noncontact procedure, the Pentacam evaluation was performed first. Then, using the pachymetric maps generated by the Pentacam (this instrument makes thickness measurements across the entire cornea perpendicular to its surface, separated by a distance of 1 m), we divided the cornea into a central circular zone of 1-mm radius (designated zone I) centered at the corneal apex (the point of maximum curvature or height, typically temporal to the center of the pupil) and several concentric rings of 1-mm width each with the same center (five rings until the corneal limbus, denoted zones II, III, IV, V, and VI, respectively, moving outward from the center; Figs. 1, 2). The variables compared between healthy controls and glaucoma patients were: power of the flattest and steepest corneal axes, position of the flattest axis (grouped as 0-30, 30-60, 60-90, FIGURE 2. The figure shows the spreadsheet onto which the Pentacam exports the corneal thicknesses. Using this diagram, we defined zones 1 to VI centered at the corneal apex (in this case, for a right eye). Note that though zones II, III, IV, and V are complete rings, zone VI is a crescent shape because in the nasal zone (right) the limbus is reached. RESULTS The two groups examined in this cross-sectional study were 126 left eyes of 126 healthy subjects and 130 left eyes of 130 patients with POAG. Table 1 provides the means and standard deviations of the corneal variables recorded. Normal distribution of data was confirmed by the Kolmogorov-Smirnov and Shapiro-Wilk tests. Our comparison of variables between control subjects and glaucoma patients (using the t-test for independent samples, assuming the homoscedasticity of the two samples supported by the Levene test) revealed significant differences in the mean thicknesses of the whole cornea and of corneal zones I to VI. No significant differences were detected in corneal powers or in CCT TABLE 1. Means of the Variables Recorded in the Control Subjects and Glaucoma Patients Mean Power steepest axis Control Glaucoma Power flattest axis Control Glaucoma CCT (ultrasound) Control Glaucoma Mean corneal thickness Control Glaucoma Thickness zone I Control Glaucoma Thickness zone II Control Glaucoma Thickness zone III Control Glaucoma Thickness zone IV Control Glaucoma Thickness zone V Control Glaucoma Thickness zone VI Control Glaucoma Powers of the corneal axes are expressed in diopters. All corneal thicknesses, including CCT, are expressed in micrometers. For definitions of the thickness zones, see Figure 2. SD
3 IOVS, May 2011, Vol. 52, No. 6 Corneal Variables in Glaucoma 3685 TABLE 2. Mean Differences between the Variables Recorded in the Controls and Glaucoma Patients Differences (control minus glaucoma) P 95% CI of the Difference Mean Difference Lower Upper Power steepest axis Power flattest axis CCT (ultrasound) Mean thickness Thickness zone I Thickness zone II Thickness zone III Thickness zone IV Thickness zone V Thickness zone VI Powers of the corneal axes are expressed in diopters. All corneal thicknesses, including CCT, are expressed in micrometers. For definitions of the thickness zones, see Figure 2. 95% CI, 95% confidence interval. determined by ultrasound pachymetry. Table 2 provides the differences in the variables observed between the two groups and their confidence intervals. Figure 3 shows the distributions of the variables that varied significantly between the two populations. The Mann-Whitney U test indicated no significant differences in the flattest corneal axis (U 1976; P 0.73). Using the AUC of the ROC to select the best regression equation able to discriminate between the presence or absence of POAG, the variables revealed as significant were the mean thicknesses of the entire cornea and of corneal zones IV and VI. The variables included in this regression model and the parameters of the logistic regression equation are provided in Table 3; the area under the ROC curve (Fig. 4) for this model was (95% confidence interval, ). The sensitivity of this model for diagnosing POAG was 67.7%, and its specificity was 63.5%. This regression model revealed that first-order interactions (products) between the predictive variables were not significant and that stratification into quartiles indicated a lack of confounding factors among the predictive variables. DISCUSSION The role of the cornea in glaucoma is becoming ever more evident since it was established that CCT conditions IOP measurement 2 7 and that greater corneal thickness is a protecting factor for the onset and advance of glaucoma Most of the recent studies in this area have addressed the effects of CCT and other new parameters, such as corneal hysteresis, on the different tonometry systems In contrast, in the present study, we considered different ring-shaped zones of the cornea of preestab- FIGURE 3. Box plots illustrating mean corneal thickness and mean thicknesses of zones I to VI recorded in the study (in which significant differences were detected between the healthy subjects and glaucoma patients). In each box, the horizontal line indicates the median, the upper and lower limits, and the third and first quartiles, respectively. Outliers are indicated with circles and are those values that appear above the third or below the first quartiles at a distance greater than 1.5 times the distance of the interquartile range (Q3 Q1). The whiskers emerging from the boxes represent values appearing above the third or below the first quartiles at a distance lower than 1.5 times the distance of the interquartile range. Thicknesses are expressed in micrometers (microns).
4 3686 Saenz-Frances et al. IOVS, May 2011, Vol. 52, No. 6 TABLE 3. Variables Entered in the Logistic Regression Equation and Their Corresponding Significance Values and Confidence Intervals P Exp(B) Lower 95% CI Limit of Exp(B) Upper 95% CI Limit of Exp(B) Mean thickness Mean thickness zone IV Mean thickness zone VI Constant AUC Exp(B) is the exponential of the coefficient of regression B. lished size centered at the corneal apex. As far as we are aware, this approach has not been previously reported in the literature. Our findings served to identify structural differences in the corneas of healthy subjects and of patients with POAG; all the subjects who participated in our study were Caucasian. In a study sample of 36 healthy Caucasians, Aghian et al. 28 recorded a mean CCT of m compared to our mean of m. In the patients with glaucoma, these authors observed a mean of m, whereas our figure was m. However, unlike the difference in CCT between healthy controls and glaucoma patients detected in the study by Aghian et al., 28 this difference was not significant in our study. Consistent with the present results, Shing et al. 29 and Kitsos et al. 30 reported similar CCT in their healthy subject and POAG patient groups. In the present study, we used ultrasound pachymetry to measure CCT because this is perhaps the most widely used method. Notwithstanding, other methods such as optical coherence tomography or even the Pentacam itself have provided highly reproducible results for this variable It remains to be clarified why ultrasound pachymetry was unable to detect CCT differences between our glaucoma patients and controls in the present study. Ultrasound pachymetry has been described as a highly reliable and reproducible method by Gunvant et al., 34 although authors such as Lackner et al. 35 claim the Pentacam shows higher interobserver reproducibility. Perhaps this worse interobserver reproducibility, along with an inability to detect CCT differences between glaucomatous and healthy populations described by us and by Shing et al. 29 and Kitsos et al., 30 is the outcome of the fact that the clinician has to visually establish the center of the cornea, whereas other pachymetry systems, such as the Pentacam, automatically locate this center. Accordingly, we found high agreement between the Pentacam CCT measures of thickness FIGURE 4. ROC curve for the logistic regression model including, as predictors, the variables mean overall corneal thickness and mean thicknesses of corneal zones IV, V, and VI. AUC at the pupil axis and minimum corneal thickness (the Pentacam estimates CCT as several measures, including thickness at the pupil axis and minimum corneal thickness) (intraclass correlation coefficient [ICC] 0.98), whereas agreement was only moderate between ultrasound pachymetry-determined CCT and thickness at the pupil axis (ICC 0.79) or minimum thickness (ICC 0.77), determined using the Pentacam (Saenz-Frances F et al. IOVS 2009;51:ARVO E-Abstract 579). The significant differences observed always indicated thinner corneal measurements in the glaucoma patients. However, given the lack of available literature data for the thicknesses of the corneal regions defined here, we do not know whether these differences could be clinically relevant in addition to being significant. To establish this relevance, we constructed a logistic regression model that revealed the variables mean thickness of the entire cornea and mean thicknesses of corneal zones IV and VI were able to discriminate between subjects with glaucoma and those without. Although not a diagnostic test in itself, the set of structural corneal variables identified showed considerable discriminatory capacity (AUC, 0.711; sensitivity, 67.7%; specificity, 63.5%). We are unaware whether these differences precede or result from the disease or its treatment. Brandt et al. 36 observed that the CCT of a person is fairly stable over time such that we speculate that the thicknesses of the zones examined here will be similarly stable. On the other hand, the histologic architecture of the cornea is similar across its center and periphery yet varies in thickness (greater in the periphery) and cell density. In effect, Mimura et al. 37 reported greater endothelial cell density in the corneal periphery. Moreover, Hamrah et al. 38 detected phenotypic differences in the dendritic cells of the corneal stroma between the central and peripheral cornea and greater density in the periphery. Similarly, Pleyer et al. 39 noted a greater density of IgM and complement molecules in the peripheral stroma, a factor correlated with autoimmune diseases of the peripheral cornea and with ulcers of noninfectious origin. Reinstein et al. 40 described that the corneal epithelium was thicker at the inferior and nasal levels. Apart from these observations, no substantial differences seem to exist between the histologic architecture and cell composition of the central and peripheral cornea. Notwithstanding, Nagayasu et al. 41 noted differences in the number of collagen fibers and their diameters between the central cornea and the periphery (more fibers of reduced diameter in the central zone), along with a greater density of proteoglycans in the central canine cornea. We do not know whether these differences between the central and peripheral cornea could somehow condition a change in corneal structure in response to high IOP or to the pressurelowering medications used by glaucoma patients. However, given the subtle nature of these differences, we feel that our findings are perhaps more consistent with the idea that a primary structural difference exists between the cornea of a person with POAG and one without POAG. Indeed, the morphometric characteristics of the optic nerve head in glaucoma have been widely explored. 42,43 Thus, when Lesk et al. 44 examined the relationship between CCT and optic nerve disc topography, they found greater shallowness
5 IOVS, May 2011, Vol. 52, No. 6 Corneal Variables in Glaucoma 3687 and thinness of the corneas in patients with POAG and those with ocular hypertension. In addition, Insull et al. 45 detected an inverse relationship between CCT and optic disc area. Wu et al. 46 related a thinner CCT to a smaller area of the neuroretinal rim and greater cup-to-disc ratio in patients with POAG but not in healthy controls. Kourkoutas et al. 47 observed a significant correlation between CCT and optic disc morphometry, determined through the Heidelberg Retina Tomograph II according to a nonlinear regression model. All these data support a structural link between CCT and optic disc morphometry, but we have yet to establish whether this relationship holds for the corneal zones described here. If such a relationship were confirmed, this would lend support to our hypothesis of an inherent difference in the corneal structure of glaucoma patients and healthy controls. As revealed by our results, corneal structure, and especially corneal thickness, may play a role that goes beyond merely acting as a confounding factor for tonometry readings in the field of glaucoma. Our main finding that corneal features, in addition to central corneal thickness, are associated with glaucoma warrant further investigation. We have yet to determine whether other corneal zones, other dimensions of these zones, or a different centering point, may provide even more interesting information. Similarly, the effects of mean corneal thickness in zones I to VI on Goldmann applanation tonometry and the new tonometers will also have to be examined, as has been reported for CCT. References 1. Quigley HA. Neuronal death in glaucoma. Prog Retin Eye Res. 1999;18: Whitacre MM, Stein R. Sources of error with use of Goldmann-type tonometers. Surv Ophthalmol. 1993;38: Whitacre MM, Stein RA, Hassanein K. The effect of corneal thickness on applanation tonometry. Am J Ophthalmol ;115: Doughty MJ, Zaman ML. Human corneal thickness and its impact on intraocular pressure measures: a review and metaanalysis approach. Surv Ophthalmol. 2000;44: Orssengo GJ, Pye DC. Determination of the true intraocular pressure and modulus of elasticity of the human cornea in vivo. Bull Math Biol. 1999;61: Gunvant P, O Leary DJ, Baskaran M, et al. Evaluation of tonometric correction factors. J Glaucoma. 2005;14: Martínez-de-la-Casa JM, Garcia-Feijoo J, Vico E, et al. Effect of corneal thickness on dynamic contour, rebound, and Goldmann tonometry. Ophthalmology. 2006;113: Herdener S, Hafizovic D, Pache M, Lautebach S, Funk J. Is the PASCAL-Tonometer suitable for measuring intraocular pressure in clinical routine? long- and short-term reproducibility of dynamic contour tonometry. Eur J Ophthalmol. 2008;18: Herdener S, Pache M, Lautebach S, Funk J. Dynamic contour tonometry (DCT) versus Goldmann applanation tonometry (GAT): a comparison of agreement and reproducibility. Graefes Arch Clin Exp Ophthalmol. 2007;245: Realini T, Weinreb RN, Hobbs G. Correlation of intraocular pressure measured with Goldmann and dynamic contour tonometry in normal and glaucomatous eyes. J Glaucoma. 2009;18: Argus WA. Ocular hypertension and central corneal thickness. Ophthalmology. 1995;102: Chatterjee A, Shah S, Bessant DA, et al. Reduction in intraocular pressure after excimer laser photorefractive keratectomy: correlation with pre-treatment myopia. Ophthalmology. 1997;104: Herndon LW, Choudhri SA, Cox T, et al. Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes. Arch Ophthalmol. 1997;115: Kass MA, Heuer DK, Higginbotham EJ, et al. The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma. Arch Ophthalmol. 2002;120: Gordon MO, Beiser JA, Brandt JD, et al. The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma. Arch Ophthalmol. 2002;120: Grewal DS, Brar GS, Grewal SP. Assessment of central corneal thickness in normal, keratoconus, and post-laser in situ keratomileusis eyes using Scheimpflug imaging, spectral domain optical coherence tomography, and ultrasound pachymetry. J Cataract Refract Surg. 2010;36: Al-Mezaine HS, Al-Amro SA, Kangave D, Al-Obeidan S, Al-Jubair KM. Comparison of central corneal thickness measurements using Pentacam and ultrasonic pachymetry in post-lasik eyes for myopia. Eur J Ophthalmol. 2010;20: Faramarzi A, Karimian F, Jafarinasab MR, Jabbarpoor Bonyadi MH, Yaseri M. Central corneal thickness measurements after myopic photorefractive keratectomy using Scheimpflug imaging, scanningslit topography, and ultrasonic pachymetry. J Cataract Refract Surg. 2010;36: Ladi JS, Shah NA. Comparison of central corneal thickness measurements with the Galilei dual Scheimpflug analyzer and ultrasound pachymetry. Indian J Ophthalmol. 2010;58: Prasher P, Muftuoglu O, Bowman RW, Cavanagh HD, McCulley JP, Mootha VV. Corneal power measurement with a rotating Scheimpflug imaging system after Descemet-stripping automated endothelial keratoplasty. J Cataract Refract Surg. 2010;36: Symes RJ, Say MJ, Ursell PG. Scheimpflug keratometry versus conventional automated keratometry in routine cataract surgery. J Cataract Refract Surg. 2010;36: Hashemi H, Mehravaran S, Rezvan F. Changes in corneal thickness, curvature, and anterior chamber depth during the menstrual cycle. Can J Ophthalmol Feb;45: Miháltz K, Kovács I, Takács A, Nagy ZZ. Evaluation of keratometric, pachymetric, and elevation parameters of keratoconic corneas with pentacam. Cornea. 2009;28: Read SA, Collins MJ. Diurnal variation of corneal shape and thickness. Optom Vis Sci. 2009;86: Moreno-Montañés J, Maldonado MJ, García N, Mendiluce L, García- Gómez PJ, Seguí-Gómez M. Reproducibility and clinical relevance of the ocular response analyzer in nonoperated eyes: corneal biomechanical and tonometric implications. Invest Ophthalmol Vis Sci. 2008;49: Touboul D, Roberts C, Kérautret J, et al. Correlations between corneal hysteresis, intraocular pressure, and corneal central pachymetry. J Cataract Refract Surg. 2008;34: Franco S, Lira M. Biomechanical properties of the cornea measured by the Ocular Response Analyzer and their association with intraocular pressure and the central corneal curvature. Clin Exp Optom. 2009;92: Aghian E, Choe JE, Lin S, Stamper RL. Central corneal thickness of Caucasians, Chinese, Hispanics, Filipinos, African Americans and Japanese in a glaucoma clinic. Ophthalmology. 2004;111: Singh RP, Goldberg I, Graham SL, Sharma A, Mohsin M. Central corneal thickness, tonometry and ocular dimensions in glaucoma and ocular hypertension. J Glaucoma. 2001;10: Kitsos G, Gartzios C, Asproudis I, Bagli E. Central corneal thickness in subjects with glaucoma and in normal individuals (with or without pseudoexfoliation syndrome). Clin Ophthalmol. 2009;3: Chen S, Huang J, Wen D, Chen W, Huang D, Wang Q. Measurement of central corneal thickness by high-resolution Scheimpflug imaging, Fourier-domain optical coherence tomography and ultrasound pachymetry. Acta Ophthalmol Jun 18. [Epub ahead of print]. 32. Jahadi Hosseini HR, Katbab A, Khalili MR, Abtahi MB. Comparison of corneal thickness measurements using Galilei, HR Pentacam, and ultrasound. Cornea. 2010;29: Fujioka M, Nakamura M, Tatsumi Y, Kusuhara A, Maeda H, Negi A. Comparison of Pentacam Scheimpflug camera with ultrasound pachymetry and noncontact specular microscopy in measuring central corneal thickness. Curr Eye Res. 2007;32: Gunvant P, Broadway DC, Watkins RJ. Repeatability and reproducibility of the BVI ultrasonic pachymeter. Eye. 2003;17: Lackner B, Schmidinger G, Pieh S, Funovics MA, Skorpik C. Repeatability and reproducibility of central corneal thickness mea-
6 3688 Saenz-Frances et al. IOVS, May 2011, Vol. 52, No. 6 surement with Pentacam, Orbscan, and ultrasound. Optom Vis Sci. 2005;82: Brandt JD, Gordon MO, Beiser JA, Lin SC, Alexander MY, Kass MA; The Ocular Hypertension Treatment Study Group. Changes in central corneal thickness over time: the ocular hypertension treatment study. Ophthalmology. 2008;115: Mimura T, Joyce NC. Replication competence and senescence in central and peripheral human corneal endothelium. Invest Ophthalmol Vis Sci. 2006;47: Hamrah P, Liu Y, Zhang Q, Dana MR. The corneal stroma is endowed with a significant number of resident dendritic cells. Invest Ophthalmol Vis Sci. 2003;44: Pleyer U, Bergmann L, Krause A, Hartmann C. Autoimmune diseases of the peripheral cornea. Immunopathology, clinical aspects and therapy. Klin Monbl Augenheilkd. 1996;208: Reinstein DZ, Archer TJ, Gobbe M, Silverman RH, Coleman DJ. Epithelial thickness in the normal cornea: three-dimensional display with Artemis very high-frequency digital ultrasound. J Refract Surg. 2008;24: Nagayasu A, Hirayanagi T, Tanaka Y, Tangkawattana P, Ueda H, Takehana K. Site-dependent differences in collagen lamellae in the corneal substantia propia of beagle dogs. J Vet Med Sci. 2009;71: Sanfilippo PG, Cardini A, Sigal IA, et al. A geometric morphometric assessment of the optic cup in glaucoma. Exp Eye Res. 2010;91: Iester M, Mikelberg FS. Optic nerve head morphologic characteristics in high-tension and normal-tension glaucoma. Arch Ophthalmol. 1999;117: Lesk MR, Hafez AS, Descovich D. Relationship between central corneal thickness and changes of optic nerve head topography and blood flow after intraocular pressure reduction in open angle glaucoma and ocular hypertension. Arch Ophthalmol. 2006;124: Insull E, Nicholas S, Ang GS, Poostchi A, Chan K, Wells A. Optic disc area and correlation with central corneal thickness, corneal hysteresis and ocular pulse amplitude in glaucoma patients and controls. Clin Experiment Ophthalmol. 2010;38: Wu RY, Zheng YF, Wong TY, et al. Relationship of central corneal thickness with optic disc parameters: The Singapore Malay Eye Study. Invest Ophthalmol Vis Sci. 2011;52: Kourkoutas D, Georgopoulos G, Maragos A, et al. New nonlinear multivariable model shows the relationship between central corneal thickness and HRTII topographic parameters in glaucoma patients. Clin Ophthalmol. 2009;3:
Jose M. Martinez-de-la-Casa, Julian Garcia-Feijoo, Ana Fernandez-Vidal, Carmen Mendez-Hernandez, and Julian Garcia-Sanchez METHODS
Ocular Response Analyzer versus Goldmann Applanation Tonometry for Intraocular Pressure Measurements Jose M. Martinez-de-la-Casa, Julian Garcia-Feijoo, Ana Fernandez-Vidal, Carmen Mendez-Hernandez, and
More informationINTRODUCTION S. HERDENER, D. HAFIZOVIC, M. PACHE, S. LAUTEBACH, J. FUNK. University Eye Hospital, Freiburg - Germany
European Journal of Ophthalmology / Vol. 18 no. 1, 2008 / pp. 39-43 Is the PASCAL -Tonometer suitable for measuring intraocular pressure in clinical routine? Long- and short-term reproducibility of dynamic
More informationCentral Corneal Thickness and its Association with Ocular Parameters
Central Corneal Thickness and its Association with Ocular Parameters Authors: An-Fei Li 1,2 Mei-Ju Chen 1,2 Affiliations: 1 Department of Ophthalmology, Taipei Veterans General Hospital 2 National Yang-Ming
More informationComparison between Pentacam HR and Orbscan II after Hyperopic Photorefractive Keratectomy
Original Article Comparison between Pentacam HR and Orbscan II after Hyperopic Photorefractive Keratectomy Mahmoud Jabbarvand 1, MD; Farshad Askarizadeh 2, PhD; Mohamad Reza Sedaghat 3, MD Hadi Ghadimi
More informationMEDICAL POLICY SUBJECT: CORNEAL ULTRASOUND PACHYMETRY. POLICY NUMBER: CATEGORY: Technology Assessment
MEDICAL POLICY SUBJECT: CORNEAL ULTRASOUND,, PAGE: 1 OF: 5 If a product excludes coverage for a service, it is not covered, and medical policy criteria do not apply. If a commercial product, including
More informationComparison of Central Corneal Thickness Measurements with Pentacam, Orbscan II, and Ultrasound Pachymeter
Comparison of Central Corneal Thickness Measurements with Pentacam, Orbscan II, and Ultrasound Pachymeter Abbas-Ali Yekta, PhD 1 Hassan Hashemi, MD 2,3 Mehdi KhabazKhoob, MSc 3 Asghar Dostdar, MSc 4 Shiva
More informationRole of Central Corneal Thickness in Circadian Intraocular Pressure Fluctuations among Patients with Primary Open Angle Glaucoma
Role of Central Corneal Thickness in Circadian Intraocular Pressure Fluctuations among Patients with Primary Open Angle Glaucoma Mohannad Albdour MD*, Karanjit Kooner MD, PHD** ABSTRACT Objectives: To
More informationCentral corneal thickness (CCT) measurement is a critical
ARTICLE Topographic Paracentral Corneal Thickness With Pentacam and Orbscan: Effect of Acoustic Factor Javier González-Pérez, O.D., M.Sc., Ph.D., Jose M. González-Méijome, O.D., Ph.D., María T. Rodríguez
More informationEffect of corneal parameters on measurements using the pulsatile ocular blood flow tonograph and Goldmann applanation tonometer
518 EXTENDED REPORT Effect of corneal parameters on measurements using the pulsatile ocular blood flow tonograph and Goldmann applanation tonometer P Gunvant, M Baskaran, L Vijaya, I S Joseph, R J Watkins,
More informationCorrelating central corneal thickness and intraocular pressure in ocular hypertension and glaucoma
VOL. 3 NO. 1 PHILIPPINE JOURNAL OF Ophthalmology JANUARY ORIGINAL ARTICLE JUNE 07 Jonathan G. Soriano, MD 1 Ma. Margarita L. Lat-Luna, MD 1, 3 Patricia M. Khu, MD 1, 1 Department of Ophthalmology and Visual
More informationINTRODUCTION MIKLOS SCHNEIDER 1, GABOR BORGULYA 2, ANDRAS SERES 1, ZOLTAN Z. NAGY 1, JANOS NEMETH 1
European Journal of Ophthalmology / Vol. 19 no. 2, 2009 / pp. 180-187 Central corneal thickness measurements with optical coherence tomography and ultrasound pachymetry in healthy subjects and in patients
More informationNIH Public Access Author Manuscript Cornea. Author manuscript; available in PMC 2014 May 29.
NIH Public Access Author Manuscript Published in final edited form as: Cornea. 2013 December ; 32(12): 1544 1548. doi:10.1097/ico.0b013e3182a7f39d. Repeatability of corneal epithelial thickness measurements
More informationCLINICAL SCIENCES. Clinical Significance of Central Corneal Thickness in the Management of Glaucoma
CLINICAL SCIENCES Clinical Significance of Central Corneal Thickness in the Management of Glaucoma Carolyn Y. Shih, MD; Joshua S. Graff Zivin, PhD; Stephen L. Trokel, MD; James C. Tsai, MD Objective: To
More informationDina H. Erickson, O.D., a Denise Goodwin, O.D., a Michael Rollins, O.D., b Amber Belaustegui, O.D., c and Chad Anderson a
Optometry (2009) 80, 169-174 Comparison of dynamic contour tonometry and Goldmann applanation tonometry and their relationship to corneal properties, refractive error, and ocular pulse amplitude Dina H.
More informationRECENT ADVANCES IN ANTERIOR SEGMENT IMAGING OF THE EYE. by Eszter Szalai, M.D. Supervisor: László Módis, M.D., Ph.D.
SHORT THESIS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY (Ph.D.) RECENT ADVANCES IN ANTERIOR SEGMENT IMAGING OF THE EYE by Eszter Szalai, M.D. Supervisor: László Módis, M.D., Ph.D. UNIVERSITY OF DEBRECEN DOCTORAL
More informationMacular Ganglion Cell Complex Measurement Using Spectral Domain Optical Coherence Tomography in Glaucoma
Med. J. Cairo Univ., Vol. 83, No. 2, September: 67-72, 2015 www.medicaljournalofcairouniversity.net Macular Ganglion Cell Complex Measurement Using Spectral Domain Optical Coherence Tomography in Glaucoma
More informationCentral corneal thickness and vascular risk factors in normal tension glaucoma
Central corneal thickness and vascular risk factors in normal tension glaucoma Aoife Doyle, Ahmed Bensaid and Yves Lachkar L Institut du Glaucome, Fondation Hoˆpital St. Joseph, Paris, France ABSTRACT.
More informationMedical Policy An independent licensee of the Blue Cross Blue Shield Association
Pachymetry Page 1 of 8 Medical Policy An independent licensee of the Blue Cross Blue Shield Association Title: Pachymetry Professional Institutional Original Effective Date: March 11, 2004 Original Effective
More informationTrue IOP No Doubt Facts and Figures Figures. Ziemer Ophthalmic Systems AG a Ziemer Group Company Allmendstrasse 11 CH-2562 Port, Switzerland
True IOP No Doubt Facts and Figures Figures and Facts Ziemer Ophthalmic Systems AG a Ziemer Group Company Allmendstrasse 11 CH-2562 Port, Switzerland There is increasing evidence that DCT measures IOP
More informationCentral corneal thickness determined with optical coherence tomography in various types of glaucoma
Br J Ophthalmol 2000;84:1233 1237 1233 Department of Ophthalmology, Ludwig-Maximilians- University, Munich, Germany M Bechmann M J Thiel B Roesen S Ullrich M W Ulbig K Ludwig Correspondence to: Martin
More informationClinical Study Evaluation of the New Digital Goldmann Applanation Tonometer for Measuring Intraocular Pressure
Ophthalmology, Article ID 461681, 5 pages http://dx.doi.org/1.1155/214/461681 Clinical Study Evaluation of the New Digital Goldmann Applanation Tonometer for Measuring Intraocular Pressure Yuta Sakaue,
More informationCLINICAL SCIENCES. Comparison of Ocular Response Analyzer Parameters in Chinese Subjects With Primary Angle-Closure and Primary Open-Angle Glaucoma
CLINICAL SCIENCES Comparison of Ocular Response Analyzer Parameters in Chinese Subjects With Primary Angle-Closure and Primary Open-Angle Glaucoma Arun Narayanaswamy, DNB; Daniel H. Su, FRCS(Edin); Mani
More informationThe Role of the RNFL in the Diagnosis of Glaucoma
Chapter 1. The Role of the RNFL in the Diagnosis of Glaucoma Introduction Glaucoma is an optic neuropathy characterized by a loss of of retinal ganglion cells and their axons, the Retinal Nerve Fiber Layer
More informationRole of central corneal thickness measurement in management of open angle glaucoma and glaucoma suspects in Calabar, Nigeria
Original Research Article Role of central corneal thickness measurement in management of open angle glaucoma and glaucoma suspects in Calabar, Nigeria Nkanga DG 1,2, Ibanga AA 1,2, Nkanga ED 2, Etim BA
More informationIntro to Glaucoma/2006
Intro to Glaucoma/2006 Managing Patients with Glaucoma is Exciting Interesting Challenging But can often be frustrating! Clinical Challenges To identify patients with risk factors for possible glaucoma.
More informationCentral corneal thickness among glaucoma patients attending Menelik II Hospital, Addis Ababa, Ethiopia
Original article Central corneal thickness among glaucoma patients attending Menelik II Hospital, Addis Ababa, Ethiopia Zelalem Gizachew 1, Abiy Mulugeta 1* Abstract Background: Glaucoma is one of the
More informationCLINICAL SCIENCES. Effect of Central Corneal Thickness, Corneal Curvature, and Axial Length on Applanation Tonometry
CLINICAL SCIENCES Effect of Central Corneal Thickness, Corneal Curvature, and Axial Length on Applanation Tonometry Markus Kohlhaas, MD; Andreas G. Boehm, MD; Eberhard Spoerl, PhD; Antje Pürsten, Dipl-Ing
More informationRetinal Nerve Fiber Layer Measurements in Myopia Using Optical Coherence Tomography
Original Article Philippine Journal of OPHTHALMOLOGY Retinal Nerve Fiber Layer Measurements in Myopia Using Optical Coherence Tomography Dennis L. del Rosario, MD and Mario M. Yatco, MD University of Santo
More informationReports. Macular Thickness as a Potential Biomarker of Mild Alzheimer s Disease
Reports Macular Thickness as a Potential Biomarker of Mild Alzheimer s Disease Although several postmortem findings in the retina of patients with Alzheimer s disease (AD) are available, 1 new biomarkers
More informationComparison of IOP measurement by ocular response analyzer, dynamic contour, Goldmann applanation, and noncontact tonometry
European Journal of Ophthalmology / Vol. 19 no. 6, 2009 / pp. 936-941 Comparison of IOP measurement by ocular response analyzer, dynamic contour, Goldmann applanation, and noncontact tonometry BANU ONCEL,
More informationDecember 2016, Volume: 8, Issue: 12, Pages: , DOI:
Electronic Physician (ISSN: 2008-5842) http://www.ephysician.ir December 2016, Volume: 8, Issue: 12, Pages: 3429-3433, DOI: http://dx.doi.org/10.19082/3429 Refinement of Intraocular Pressure Measurements
More informationCentral Corneal Thickness-An important variable for prognostication in Primary Open Angle glaucoma; A Kolkata based study in Eastern India
Original article: Central Corneal Thickness-An important variable for prognostication in Primary Open Angle glaucoma; A Kolkata based study in Eastern India 1Dr. Apala Bhattacharya, 2 Dr Gautam Bhaduri,
More informationBased on the studies by Goldmann and Schmidt 1 and Ehlers. Central Corneal Thickness Correlated with Glaucoma Damage and Rate of Progression
Central Corneal Thickness Correlated with Glaucoma Damage and Rate of Progression Jost B. Jonas, 1,2 Andrea Stroux, 3,4 Isabel Velten, 1 Anselm Juenemann, 1 Peter Martus, 3 and Wido M. Budde 1,2 PURPOSE.
More informationInternational Journal of Health Sciences and Research ISSN:
International Journal of Health Sciences and Research www.ijhsr.org ISSN: 2249-9571 Original Research Article Conversion of Ocular Hypertensives into Glaucoma: A Retrospective Study Aditi Singh 1, Shibi
More information* Şükrü Bayraktar, MD, Zerrin Bayraktar, MD, and Ömer Faruk Yilmaz, MD
Journal of Glaucoma 10:163 169 2001 Lippincott Williams & Wilkins, Inc. Influence of Scan Radius Correction for Ocular Magnification and Relationship Between Scan Radius With Retinal Nerve Fiber Layer
More informationPolicy #: 354 Latest Review Date: July 2011
Name of Policy: Corneal Hysteresis Policy #: 354 Latest Review Date: July 2011 Category: Medicine Policy Grade: Active Policy but no longer scheduled for regular literature reviews and updates. Background/Definitions:
More informationGlaucoma: Diagnostic Modalities
Glaucoma: Diagnostic Modalities - Dr. Barun Kumar Nayak, Dr. Sarika Ramugade Glaucoma is a leading cause of blindness in the world, especially in older people. Early detection and treatment by ophthalmologist
More informationAccuracy and Repeatability of a New Portable Ultrasound Pachymeter
Accuracy and Repeatability of a New Portable Ultrasound Pachymeter Queirós A 1, González-Méijome JM 1, Fernandes P 1, Jorge J 1, Almeida J B 1, Parafita MA 2 1 Department of Physics (Optometry), School
More informationAn Ultra-High-Speed Scheimpflug Camera for Evaluation of Corneal Deformation Response and Its Impact on IOP Measurement
Glaucoma An Ultra-High-Speed Scheimpflug Camera for Evaluation of Corneal Deformation Response and Its Impact on IOP Measurement Christopher Kai-Shun Leung, 1 Cong Ye, 1 and Robert N. Weinreb 2 1 Department
More informationRelationship between central corneal thickness and parameters of optic nerve head topography in healthy subjects
European Journal of Ophthalmology / Vol. 18 no. 1, 2008 / pp. 32-38 Relationship between central corneal thickness and parameters of optic nerve head topography in healthy subjects A.B. CANKAYA, U. ELGIN,
More informationInterpretation of corneal tomography
Interpretation of corneal tomography Presented by Chameen Samarawickrama - Westmead Hospital - Liverpool Hospital - University of Sydney - University of New South Wales The University of Sydney Page 1
More informationScanning Laser Tomography to Evaluate Optic Discs of Normal Eyes
Scanning Laser Tomography to Evaluate Optic Discs of Normal Eyes Hiroshi Nakamura,* Toshine Maeda,* Yasuyuki Suzuki and Yoichi Inoue* *Eye Division of Olympia Medical Clinic, Tokyo, Japan; Department of
More informationThe Effect of Pupil Dilation on Scanning Laser Polarimetry With Variable Corneal Compensation
C L I N I C A L S C I E N C E The Effect of Pupil Dilation on Scanning Laser Polarimetry With Variable Corneal Compensation Amjad Horani, MD; Shahar Frenkel, MD, PhD; Eytan Z. Blumenthal, MD BACKGROUND
More informationCENTRAL CORNEAL THICKNESS; COMPARISON OF CENTRAL CORNEAL THICKNESS MEASUREMENTS BY PENTACAM AND ULTRASOUND PACHYMETRY, IN MYOPIC AND KERATOCONUS EYES.
The Professional Medical Journal DOI: 10.29309/TPMJ/18.4609 1. FCPS Assistant Professor Allied Hospital, Punjab Medical College, Faisalabad, Pakistan. 2. FCPS Assistant Professor Liaquat University of
More informationINTRODUCTION J. DAWCZYNSKI, E. KOENIGSDOERFFER, R. AUGSTEN, J. STROBEL. Department of Ophthalmology, University Hospital Jena, Jena - Germany
European Journal of Ophthalmology / Vol. 17 no. 3, 2007 / pp. 363-367 Anterior segment optical coherence tomography for evaluation of changes in anterior chamber angle and depth after intraocular lens
More informationRecent concerns regarding the depth of tissue ablation with
Volume Estimation of Excimer Laser Tissue Ablation for Correction of Spherical Myopia and Hyperopia Damien Gatinel, 1 Thanh Hoang-Xuan, 1 and Dimitri T. Azar 1,2 PURPOSE. To determine the theoretical volumes
More informationInfluence of Myopic Disc Shape on the Diagnostic Precision of the Heidelberg Retina Tomograph
Influence of Myopic Disc Shape on the Diagnostic Precision of the Heidelberg Retina Tomograph Yoshio Yamazaki,* Keiji Yoshikawa, Shiho Kunimatsu, Nobuyuki Koseki, Yasuyuki Suzuki, Shun Matsumoto and Makoto
More informationCataract Surgery in the Patient with a History of LASIK or PRK
Cataract Surgery in the Patient with a History of LASIK or PRK #56996-RS April 2018 Sebastian Lesniak, MD Matossian Eye Associates None Disclosures Bio Matossian Eye Associates, Hopewell NJ, 7/2015 Present
More informationStudy of Retinal Nerve Fiber Layer Thickness Within Normal Hemivisual Field in Primary Open-Angle Glaucoma and Normal-Tension Glaucoma
Study of Retinal Nerve Fiber Layer Thickness Within Normal Hemivisual Field in Primary Open-Angle Glaucoma and Normal-Tension Glaucoma Chiharu Matsumoto, Shiroaki Shirato, Mai Haneda, Hiroko Yamashiro
More informationPeretyagin O.A., Cand. Med. Sc., Ass. Prof.; Dmitriev S.K., Dr. Med. Sc., Prof.; Lazar Yu.M., Cand. Med. Sc.; Tatarina Yu.A., Junior Research Fellow
Changes in corneoscleral rigidity and corneal thickness at various target intraocular pressures in patients with stabilized primary open-angle glaucoma Peretyagin O.A., Cand. Med. Sc., Ass. Prof.; Dmitriev
More informationPearls for the Refractive Technician Fadiah Alkhawaldeh, IMBA, COT, ROUB
Pearls for the Refractive Technician Fadiah Alkhawaldeh, IMBA, COT, ROUB Cleveland Clinic Cole Eye Institute OOS, Columbus, OH February, 2014 alkhawf@ccf.org NO FINANCIAL DISCLOSURES A Puzzle of an Eye
More informationTargeting Intraocular Pressure in Glaucoma: a Teaching Case Report 1
Targeting Intraocular Pressure in Glaucoma: a Teaching Case Report 1 By: Andrew Kemp, OD, Marcus Gonzales, OD, FAAO, Joe DeLoach, OD, FAAO, and Zanna Kruoch, OD FAAO Background Glaucoma is a range of conditions
More informationOptic nerve head morphometry in healthy adults using confocal laser scanning tomography
761 SCIENTIFIC REPORT Optic nerve head morphometry in healthy adults using confocal laser scanning tomography M M Hermann, I Theofylaktopoulos, N Bangard, C Jonescu-Cuypers, S Coburger, M Diestelhorst...
More informationEarly Detection Of Glaucoma Clinical Clues. Points To Live By. Glaucoma Risk Factors 10/3/2014
Early Detection Of Glaucoma Clinical Clues Eric E. Schmidt, O.D. Omni Eye Specialists Wilmington, NC schmidtyvision@msn.com Points To Live By 25% of G pxs NEVER have IOP >21mm 50% of G pxs have trough
More informationRetinal Nerve Fiber Layer Thickness Changes in Patients with Age-Related Macular Degeneration Treated with Intravitreal Ranibizumab
Glaucoma Retinal Nerve Fiber Layer Thickness Changes in Patients with Age-Related Macular Degeneration Treated with Intravitreal Ranibizumab Jose M. Martinez-de-la-Casa, Aurora Ruiz-Calvo, Federico Saenz-Frances,
More informationCollaboration in the care of glaucoma patients and glaucoma suspects. Barry Emara MD FRCS(C) Nico Ristorante November 29, 2012
Collaboration in the care of glaucoma patients and glaucoma suspects Barry Emara MD FRCS(C) Nico Ristorante November 29, 2012 Goals of Collaboration Patient-centred and evidence based approach Timely access
More informationComparison of Goldmann applanation tonometry and dynamic contour tonometry in healthy and glaucomatous eyes
(2009) 23, 262 269 & 2009 Macmillan Publishers Limited All rights reserved 0950-222X/09 $32.00 www.nature.com/eye CLINICAL STUDY Comparison of Goldmann applanation tonometry and dynamic contour tonometry
More informationA Formula to Predict Spectral Domain Optical Coherence Tomography (OCT) Retinal Nerve Fiber Layer Measurements Based on Time Domain OCT Measurements
pissn: 1011-8942 eissn: 2092-9382 Korean J Ophthalmol 2012;26(5):369-377 http://dx.doi.org/10.3341/kjo.2012.26.5.369 Original Article A Formula to Predict Spectral Domain Optical Coherence Tomography (OCT)
More informationCorneal Power Measurements Using Scheimpflug Imaging in Eyes With Prior Corneal Refractive Surgery
Corneal Power Measurements Using Scheimpflug Imaging in Eyes With Prior Corneal Refractive Surgery Jack T. Holladay, MD, MSEE, FACS; Warren E. Hill, MD, FACS; Andreas Steinmueller, MSc ABSTRACT PURPOSE:
More informationLaser in situ keratomileusis (LASIK) has
Changes in Intraocular Pressure After Laser in situ Keratomileusis Khaled M. Rashad, MD; Ahmed A. Bahnassy, MSc, PhD ABSTRACT PURPOSE: To evaluate changes in intraocular pressure (IOP) measurements by
More informationNoel de Jesus Atienza, MD, MSc and Joseph Anthony Tumbocon, MD
Original Article Philippine Journal of OPHTHALMOLOGY Diagnostic Accuracy of the Optical Coherence Tomography in Assessing Glaucoma Among Filipinos. Part 1: Categorical Outcomes Based on a Normative Database
More informationRETINAL NERVE FIBER LAYER
CLINICAL SCIENCES The Effect of Scan Diameter on Retinal Nerve Fiber Layer Thickness Measurement Using Stratus Optic Coherence Tomography Giacomo Savini, MD; Piero Barboni, MD; Michele Carbonelli, MD;
More informationCorneal Hysteresis and Visual Field Asymmetry in Open Angle Glaucoma SUBJECTS AND METHODS
Glaucoma Corneal Hysteresis and Visual Field Asymmetry in Open Angle Glaucoma Aashish Anand, 1 Carlos Gustavo V. De Moraes, 1,2 Christopher C. Teng, 1,2,3 Celso Tello, 1,3 Jeffrey M. Liebmann, 1,2 and
More information53 year old woman attends your practice for routine exam. She has no past medical history or family history of note.
Case 1 Normal Tension Glaucoma 53 year old woman attends your practice for routine exam. She has no past medical history or family history of note. Table 1. Right Eye Left Eye Visual acuity 6/6 6/6 Ishihara
More informationAnterior segment imaging
CET CONTINUING Sponsored by 1 CET POINT Anterior segment imaging Sundeep Vaswani, BSc (Hons), MCOptom 39 The anterior segment of the eye encompasses all structures from the front surface of the cornea
More informationCentral and Peripheral Changes in Anterior Corneal Topography after Orthokeratology and Laser in situ Keratomileusis
Central and Peripheral Changes in Anterior Corneal Topography after Orthokeratology and Laser in situ Keratomileusis Han-Yin Sun 1, 2, 3, Hsiu-Wan Yang 4, I-Tsung Wu 4, Jung-Kai Tseng 2, 3 1, 5* and Shun-Fa
More informationNIIOS. Cornea Specialist, Melles Cornea Clinic, NIIOS, Rotterdam, the Netherlands Naval Hospital, Athens, Greece VASILIS S.
Cornea Specialist, Melles Cornea Clinic, NIIOS, Rotterdam, the Netherlands Naval Hospital, Athens, Greece Goldman applanation tonometry is still the gold standard for measuring IOP, but its accuracy is
More informationComparison of Corneal Thickness with Online Optical Coherence Pachymetry and Ultrasound Pachymeter
Comparison of Corneal Thickness with Online Optical Coherence Pachymetry and Ultrasound Pachymeter Rany E. Mitwally 1, MD, M. Tarek El-Naggar 1, MD, FRCS, Mohamed A. Marzouk 1 *, MD. 1 Research Institute
More informationComparative evaluation of time domain and spectral domain optical coherence tomography in retinal nerve fiber layer thickness measurements
Original article Comparative evaluation of time domain and spectral domain optical coherence tomography in retinal nerve fiber layer thickness measurements Dewang Angmo, 1 Shibal Bhartiya, 1 Sanjay K Mishra,
More informationNew Normative Database of Inner Macular Layer Thickness Measured by Spectralis OCT Used as Reference Standard for Glaucoma Detection
Article https://doi.org/10.1167/tvst.7.1.20 New Normative Database of Inner Macular Layer Thickness Measured by Spectralis OCT Used as Reference Standard for Glaucoma Detection María Nieves-Moreno 1,2,
More informationThe two currently accepted methods for correcting
New Technique Therapeutic Alloplastic Laser in situ Keratomileusis for Myopia Arturo Maldonado-Bas, MD; Ruben Pulido-Garcia, MD ABSTRACT BACKGROUND: A new technique, therapeutic alloplastic laser in situ
More informationSeiji T. Takagi, Yoshiyuki Kita, Asuka Takeyama, and Goji Tomita. 1. Introduction. 2. Subjects and Methods
Ophthalmology Volume 2011, Article ID 914250, 5 pages doi:10.1155/2011/914250 Clinical Study Macular Retinal Ganglion Cell Complex Thickness and Its Relationship to the Optic Nerve Head Topography in Glaucomatous
More informationStructural examina.on: Imaging
ManaMa: Glaucoma Structural examina.on: Imaging Luís Abegão Pinto, MD, PhD Department of Ophthalmology CHLC Lisbon Faculty of Medicine, Lisbon University 1 11-10- 2013 Structural changes Qualitative changes
More informationRetinal nerve fiber layer thickness in Indian eyes with optical coherence tomography
Original articles in Indian eyes with optical coherence tomography Malik A, Singh M, Arya SK, Sood S, Ichhpujani P Department of Ophthalmology Government Medical College and Hospital, Sector 32, Chandigarh,
More informationAnalysis of differences in intraocular pressure evaluation performed with contact and non-contact devices
Lanza et al. BMC Ophthalmology (2018) 18:233 https://doi.org/10.1186/s12886-018-0900-5 RESEARCH ARTICLE Open Access Analysis of differences in intraocular pressure evaluation performed with contact and
More informationRelationship of Central Corneal Thickness with Optic Disc Parameters: The Singapore Malay Eye Study METHODS
Glaucoma Relationship of Central Corneal Thickness with Optic Disc arameters: The Singapore Malay Eye Study Ren-Yi Wu, 1 Ying-Feng Zheng, 1 Tien-Yin Wong, 1,2 Carol Yim-Lui Cheung, 1 Seng-Chee Loon, 3
More informationSpontaneous Intraocular Pressure Reduction in Normal-Tension Glaucoma and Associated Clinical Factors
CLINICAL INVESTIGATIONS Spontaneous Intraocular Pressure Reduction in Normal-Tension Glaucoma and Associated Clinical Factors Akihiro Oguri, Tetsuya Yamamoto and Yoshiaki Kitazawa Department of Ophthalmology,
More informationThe Ocular Response Analyzer (ORA; Reichert Ophthalmic
Glaucoma Lack of Association Between Corneal Hysteresis and Corneal Resistance Factor With Glaucoma Severity in Primary Angle Closure Glaucoma Monisha E. Nongpiur, 1,2 Owen Png, 2 Jestin W. Chiew, 3 Kenric
More informationGanglion cell complex scan in the early prediction of glaucoma
Original article in the early prediction of glaucoma Ganekal S Nayana Super Specialty Eye Hospital and Research Center, Davangere, Karnataka, India Abstract Objective: To compare the macular ganglion cell
More informationComparison of Optic Disc Topography Measured by Retinal Thickness Analyzer with Measurement by Heidelberg Retina Tomograph II
Comparison of Optic Disc Topography Measured by Retinal Analyzer with Measurement by Heidelberg Retina Tomograph II Noriko Itai*, Masaki Tanito*, and Etsuo Chihara* *Senshokai Eye Institute, Uji, Kyoto,
More informationMorphological Study of Corneal Endothelium and Corneal Thickness in Pseudoexfoliation Syndrome
LABORATORY INVESTIGATIONS Morphological Study of Corneal Endothelium and Corneal Thickness in Pseudoexfoliation Syndrome Kenji Inoue*,, Kazuko Okugawa*,, Tetsuro Oshika and Shiro Amano *Department of Ophthalmology,
More informationClinical decision making based on data from GDx: One year observations
Washington University School of Medicine Digital Commons@Becker Open Access Publications 2002 Clinical decision making based on data from GDx: One year observations James C. Bobrow Washington University
More informationManagement of Unpredictable Post-PRK Corneal Ectasia with Intacs Implantation
Management of Unpredictable Post-PRK Corneal Ectasia with Intacs Implantation Mohammad Naser Hashemian, MD 1 Mahdi AliZadeh, MD 2 Hassan Hashemi, MD 1,3 Firoozeh Rahimi, MD 4 Abstract Purpose: To present
More informationRefractive Surgery Dilemma
Refractive Surgery Dilemma Section Editor: lireza aradaran-rafii, MD CSE PRESENTTION 33-year-old man seeking refractive surgery presented with refractive error of -1.75-4.0 20 in the right and -0.75-2.5
More informationParafoveal Scanning Laser Polarimetry for Early Glaucoma Detection
Yamanashi Med. J. 18(1), 15~ 20, 2003 Original Article Parafoveal Scanning Laser Polarimetry for Early Glaucoma Detection Satoshi KOGURE, Yoshiki TODA, Hiroyuki IIJIMA and Shigeo TSUKAHARA Department of
More informationComparison of Corneal and Anterior Chamber Parameters following Myopic laser in situ keratomileusis and photorefractive keratectomy by
Comparison of Corneal and Anterior Chamber Parameters following Myopic laser in situ keratomileusis and photorefractive keratectomy by Pentacam as A New Imaging Technique Mohammad Ali Zare, MD 1 Hassan
More informationKeratoconus Clinic. Optometric Co-management Opportunities
Keratoconus Clinic Optometric Co-management Opportunities The Bochner Eye Institute established the first Keratoconus Clinic in Canada in 2008. The consultation and advanced imaging are OHIP covered. All
More informationChanges in Central Corneal Thickness over Time
Changes in Central Corneal Thickness over Time The Ocular Hypertension Treatment Study James D. Brandt, MD, 1 Mae O. Gordon, PhD, 2 Julia A. Beiser, MS, 2 Shan C. Lin, MD, 3 Monica Y. Alexander, MD, 4
More informationClinical Profile of Primary Open Angle Glaucoma Suspects.
DOI: 10.21276/aimdr.2018.4.2.OT3 Original Article ISSN (O):2395-2822; ISSN (P):2395-2814 Clinical Profile of Primary Open Angle Glaucoma Suspects. Pradnya Abhinav Mohan 1 1 Fellow Phaco-surgery, Department
More informationIntraocular pressure changes and relationship. Corneal Biomechanics After SMILE and FS-LASIK
Cornea Intraocular Pressure Changes and Relationship With Corneal Biomechanics After SMILE and FS-LASIK Hua Li, Yan Wang, Rui Dou, Pinghui Wei, Jiamei Zhang, Wei Zhao, and Liuyang Li Tianjin Eye Hospital
More informationBilateral Microphthalmos Associated with Papillomacular Fold, Severe Hyperopia and Steep Cornea
Bilateral Microphthalmos Associated with Papillomacular Fold, Severe Hyperopia and Steep Cornea Mojtaba Abrishami, MD 1 Alireza Maleki, MD 2 Ali Hamidian-Shoormasti, MD 3 Mostafa Abrishami, MD 4 Abstract
More information4/06/2013. Medication Observation POAG. Proportion. Native American 0.1% 0.4%
Clinical Research in Glaucoma: Putting Science into Practice J. James Thimons, O.D., FAAO Chairman, National Glaucoma Society www.nationalglaucomasociety.org Ocular Hypertension Treatment Study (OHTS)
More informationInvestigation of the relationship between central corneal thickness and retinal nerve fiber layer thickness in ocular hypertension
Acta Medica Anatolia Volume 2 Issue 1 2014 Investigation of the relationship between central corneal thickness and retinal nerve fiber layer thickness in ocular hypertension Remzi Mısır 1, Sinan Sarıcaoğlu
More informationA Review Of Risk Factors. Early Detection Of Glaucoma Clinical Clues. A risk factor analysis is critical. Points To Live By
A Review Of Risk Factors Early Detection Of Glaucoma Clinical Clues Eric E. Schmidt, O.D. Omni Eye Specialists Wilmington, NC schmidtyvision@msn.com FINDACAR Family history IOP Nearsightedness Diabetes/Vascular
More informationInterest in central corneal thickness (CCT) and glaucoma was. Central Corneal Thickness and Glaucoma in East Asian People.
Glaucoma Central Corneal Thickness and Glaucoma in East Asian People Alexander C. Day, 1,2 David Machin, 3 Tin Aung, 4 Gus Gazzard, 2 Rahat Husain, 4 Paul T. K. Chew, 5 Peng T. Khaw, 1,2,6 Steve K. L.
More informationEfficacy of Photorefractive Keratectomy for Military Pilot Recruitment in an Asian Air Force
Efficacy of Photorefractive Keratectomy for Military Pilot Recruitment in an Asian Air Force Brian See, Gerard Nah, Wee Hoe Gan, Robin Low AsMA Annual Scientific Meeting 2013 Chicago, IL, USA Disclosure
More informationCentral corneal thickness and normal tension glaucoma: A cross-sectional study
Optometry (2006) 77, 134-140 Central corneal thickness and normal tension glaucoma: A cross-sectional study Michael Sullivan-Mee, O.D., a Kathy D. Halverson, O.D., a Mollie C. Saxon, O.D., a Glenn B. Saxon,
More informationA comparison of HRT II and GDx imaging for glaucoma detection in a primary care eye clinic setting
(2007) 21, 1050 1055 & 2007 Nature Publishing Group All rights reserved 0950-222X/07 $30.00 www.nature.com/eye CLINICAL STUDY A comparison of HRT II and GDx imaging for glaucoma detection in a primary
More informationThe Harvard community has made this article openly available. Please share how this access benefits you. Your story matters.
Central Corneal Thickness in Highly Myopic Eyes: Inter-device Agreement of Ultrasonic Pachymetry, Pentacam and Orbscan II Before and After Photorefractive Keratectomy The Harvard community has made this
More informationEffects of laser in situ keratomileusis (LASIK) on corneal biomechanical measurements with the Corvis ST tonometer
Clinical Ophthalmology open access to scientific and medical research Open Access Full Text Article Original Research Effects of laser in situ keratomileusis (LASIK) on corneal biomechanical measurements
More information