Dry Eye Symptoms and Signs in Long-Term Contact Lens Wearers

Transcription

1 Coll. Antropol. 37 (2013) Suppl. 1: Professional paper Dry Eye Symptoms and Signs in Long-Term Contact Lens Wearers Snje`ana Ka{telan 1, Adrian Lukenda 2, Jasminka Salopek-Rabati} 1, Josip Pavan 1 and Marta Gotovac 3 1 Department of Ophthalmology, Clinical Hospital Dubrava, Zagreb, Croatia 2 Opto Centar Eye Centre, Zagreb, Croatia 3 Department of Ophthalmology, General Hospital Po`ega, Po`ega, Croatia ABSTRACT The aim of this study is to analyze the relationship between the self-reported symptoms and objective signs of dry eye disease in long-term rigid gas-permeable (RGP) or soft contact lens (SCL) wearers. The study included 32 eyes of Caucasian RGP and SCL wearers between the age of 21 and 42 who wore contact lenses continuously on a daily basis for more than 2 years. Symptoms were assessed according to the Ocular Surface Disease Index (OSDI). Clinical assessments included corneal fluorescein staining according to the National Eye Institute (NEI) staining grid, tear film break-up time (TBUT) and Schirmer II test. There were more male (62.5%) than female (37.5%) patients with a higher proportion of RGP wearers among males (40% vs. 17%) in the study. The mean duration of daily lens wear was 10.6 ± 5.37 hours, with a significantly higher proportion of patients who wore their lenses for prolonged hours in the soft contact lens group (p<0.05). There was a trend towards a higher proportion of self reported mild and moderate dry eye in females and soft contact lens wearers. No RGP wearer in this study had a NEI corneal staining grid score higher than 2. A moderate negative correlation was found between daily lens wear duration and TBUT (Pearson s coefficient, r= 0.47) as well as Schirmer II values and higher OSDI score, i.e. mild and moderate dry eye categories (r= 0.50). A strong positive correlation was found between and TBUT and Schirmer II values (r=0.74). The results of the study emphasize the importance of early and accurate diagnosis of dry eye disease for successful long term RGP and SCL contact lens wear which will hopefully motivate future larger scale investigations on dry eye related problems in contact lens wearers. Key words: dry eye, contact lens, soft, RGP, OSDI, TBUT, Schirmer test Introduction Dry eyes, redness and foreign body sensation are common complaints among contacts lens wearers. These symptoms are more prevalent in contact lens wearers than in general population 1. Due to changes associated with dry eye these patients also often complain of visual impairment and blurred vision 2. The mentioned symptoms and disturbances appear to be more common in the evening than during the day 3. Previously conducted investigations estimate that the frequency of contact lens related dry eye is approximately 50% 1,3,4. Besides blurred vision dry eye symptoms in contact lens wearers is also associated with reductions in daily wearing time and an increased risk of ocular surface dryness and infection 5,6. Discomfort and desiccation symptoms are the primary reasons for contact lens intolerance, a reduction in the length of wearing time and eventual discontinuation 7. In a study conducted to investigate the reasons for cessation of wearing contact lenses 51% of the participants reported discomfort as the main reason 8. It has been suggested that potential pathogenesis of contact lens-related dry eye include tear hyperevaporation 9, inflammation of the ocular surface 10, reduced capability of tear glands to produce tears of optimal composition with concurrent increased osmolality 11, dryness related to lack of biocompatibility of the lens surface 12,or any combination of these mechanisms. The diagnosis of dry eye is set on the basis of patients self-report of symptoms and clinical examinations. The examinations usually include the tear break up time test (TBUT) as an indicator of tear film stability, the Schir- Received for publication September 3,

2 mer test which measures the tear production as well as corneal and conjunctival staining for assessment of ocular surface epithelial damage 13. However, the correlation between the dry eye subjective symptoms severity and clinical dry eye tests are frequently inconsistent 10,13.To facilitate the diagnosis several patient-reported outcome (PRO) questionnaires are available so as to give useful information which can aid in the identification and assessment of the severity of dry eye disease symptoms. The Ocular Surface Disease Index (OSDI) is one of the most commonly used PRO questionnaires and includes the three segments: ocular symptoms, vision-related function and environmental triggers 14. It is known that long-term contact lens wear can decrease corneal thickness and increase the corneal curvature and surface irregularity 15. However, despite a significant change in materials and designs of RGP lenses in the last 20 years and yet still a significant number of RGP fits in some Western countries, the evidence about differences in dry eye symptoms and signs between long term RGP and soft contact lenses wearers is scarce 16. The aim of this report is to analyze the relationship between the subjective self-reported symptoms and objective signs of dry eye disease in patients who wear rigid gas-permeable (RGP) or soft contact lenses (SCL). Materials and methods The study included 16 Caucasian (32 eyes) daily long- -term wearers of rigid gas-permeable and soft contact lens between the ages of 21 and 42. Patients included in the study had to wear contact lenses on daily basis continuously for more than 2 years and remove the lenses two days prior to evaluation. Conversely patients being treated for ocular infection within 4 weeks, those who used artificial tear preparations within one week, had a history of refractive and other corneal surgeries or presented with eyelid anomalies were excluded from the study. The lens materials varied in their oxygen permeability (Dk) values. The Dk value of RGP lenses worn by participants was between 28 and 100 Dk whereas the soft lens materials had a Dk values between 9 and 110. Symptoms of ocular dryness were assessed using the Ocular Surface Disease Index (OSDI). The OSDI scores were calculated according to the formula recommended by Schiffman et al 17. The additional questionnaire included data on average daily contact lens wear time and systemic and/or local therapy. Clinical assessments included corneal fluorescein staining, tear film break-up time (TBUT) and Schirmer II test. Corneal staining was graded using the National Eye Institute (NEI) staining grid in which a score of 0 3 (0 normal and 3 severe) was assigned to each of five corneal regions (central, nasal, temporal, superior, and inferior) with a maximum total score of 15. Patients were divided in two groups depending on the corneal staining score for each eye with a grade <2 in either zone representing the threshold for a normal finding. Statistical data analysis was based on inferential statistics performed with commercially available software (SPSS ver for Windows). Our goal was to estimate the difference in population proportions and determine the correlation between tested variables by using the Pearson s correlation coefficient (r). As the tested variables had no functional relationship, correlation analysis was used to determine the strength of the statistical or stochastic relationships. Results The demographic data and the percentage of soft and rigid gas permeable (RGP) wearers according to gender, age and the duration of daily lens wear is presented in Table 1. There were more male (62.5%) than female (37.5%) patients with a higher proportion of RGP wear- TABLE 1 PATIENT DEMOGRAPHIC DATA AND THE PERCENTAGE OF SOFT AND RIGID GAS PERMEABLE WEARERS ACCORDING TO GENDER, AGE, DURATION OF DAILY LENS WEAR AND NEI CORNEAL STAINING SCORES N SCL (%) RGP (%) Total Gender Age (years) Daily lens wear duration (hours) NEI corneal staining grid Male Female > * *p<0.05, SCL soft contact lens, RGP rigid gas-permeable, NEI National Eye Institute 200

3 TABLE 2 THE FREQUENCY OF NORMAL, MILD AND MODERATE OSDI SCORES ACCORDING TO GENDER, AGE, DURATION OF DAILY LENS WEAR AND CONTACT LENS TYPE N OSDI Normal (%) Mild (%) Moderate (%) Total Gender Age (years) Daily lens wear duration (hours) Contact lens type Male Female > SCL RGP OSDI Ocular Surface Disease Index, SCL soft contact lens, RGP rigid gas-permeable ers among males (40% vs. 17%). The mean age of all contact lens wearers was 32 ±6.3 years. The patients wore their lenses from 2 to 25 years prior to presentation (mean 7.2 years). The mean duration of daily lens wear was 10.6±5.37 hours, with a significantly higher proportion of patients who wore their lenses for prolonged hours in the soft contact lens group (p<0.05). No RGP wearer in this study had a NEI corneal staining grid score higher than 2. The frequency of each OSDI category classified by gender, age, daily lens wear duration and contact lens type are shown in Table 2. There was a trend towards a higher proportion of self reported mild and moderate dry eye in females and soft contact lens wearers, with no statistical significant difference. A moderate negative correlation was found between daily lens wear duration and TBUT (r= 0.47) as well as Schirmer II values and OSDI score (r= 0.50). A strong positive correlation was found between and TBUT and Schirmer II values (r=0.74). There was a weak negative correlation between years of continuous contact lens wear, tear break-up time and higher OSDI scores, i.e. mild and moderate OSDI categories (r= 0.30 and r= 0.30 respectively). A weak correlation was also found between years of contact lens wear and TBUT (r= 0.25) and daily lens wear duration and higher OSDI values (r=0.23). Discussion Dry eye is the most common reason for contact lens discontinuation. Tear film quality and stability, oxygen deficiency, eyelid disorders, infections and allergies of the ocular surface as well as environmental conditions and local or systemic medications may perpetuate dry eye and thus contribute to the problem. Successful contact lens wear is highly dependent on the quality of tear film and therefore it is crucial to assess its features prior and particularly whilst wearing contact lens wear 2 4,18. The diagnosis of ocular surface disorders including dry eye disease relies on both clinical objective diagnostic procedures as well as the patients self-reported symptoms. For this purpose a variety of procedures are available to practitioners. Despite some drawbacks, the Ocular Surface Disease Index (OSDI) is still one of the most commonly used measuring tools which attempts to give an objective insight to patients self-report symptoms 13,17,19. Our pilot study consisted of a relatively small sample group (16 patients, 32 eyes). Due to the relatively small sample of soft contact lens wearers, we did not separate the conventional hydrogel and silicone hydrogel lens wearers in two groups. Nevertheless, when compared to other recent studies, a relatively large proportion in our study group were RGP wearers (31%) Our investigation included mainly long time lens wearers from 2 to 25 years prior to data collection (mean 7.2 years). Long time wear of contact lenses has a significant effect on tear film stability and ocular surface 23,24. In regards to the length of daily contact lens wear, a statistically higher proportion of soft contact wearers in our study wore their lenses longer than the recommended 8 hours per day when compared to the rigid gas permeable lens wearers (90% versus 10%). Future trials could provide an answer if this was due to the poor compliance to lens wear recommendations of soft contact lens wearers or to the better comfort of this type of lenses. It is interesting to note that no RGP lens wearer included in our study had significant corneal staining, 201

4 which was not a case with soft lens wearers. All patients with NEI corneal staining score of 2 or more had a superficial punctuate type of staining which included the inferior corneal region according to NEI staining grid, a pattern typical for hydrogel lens wear (data not shown). It should be mentioned that in larger studies, 3 and 9 o clock staining can been found in a certain percentage of RGP wearers. This type of staining is usually asymptomatic yet it is considered to be a contra-indication for extended wear of RGP lenses 25. In our study a higher OSDI score was found in the group of soft contacts lens wearers with 18% having mild and 27% having moderate OSDI scores. On the other hand 80% of RGP lens wearers had a normal score and no RGP patient had moderate OSDI score. This could be due to the significant portion soft contact lenses who wore their lenses longer than the advised 8 hours as compared to the RGP lens wearers who were more likely to adhere to the recommendations for length of daily wearing. Further, a higher OSDI score was found amongst women (17% had mild and 50% had moderate ODSI score) whilst we noted a normal OSDI score in 80% of men. This data is also consistent with results obtained by other researches 12,25 and can be explained by a more pronounced influence of hormones in woman or consequently that women are generally more likely to report symptoms of disease than are men 26,27. According to our results a longer period of daily lens wear had a moderate negative correlation with TBUT values (r= 0.47), meaning it had an impact on the subjective experience of comfort measured using the OSDI questionnaire. This fact supports the consideration that the soft lens wearers have a higher percentage of self-reported mild and moderate dry eye according to OSDI scores. A similar result was also found in the correlation of the Schirmer test and ODSI score respectively (r= 0.50). This result can be explained by the fact that a smaller volume of tears could lead to a stronger feeling of discomfort and thus a larger OSDI score. A negative correlation between years of continuous daily contact lens wear as well as TBUT and higher OSDI scores may be in part explained by the separation of the tear film. It has been established that contact lenses separate the precorneal tear film into a pre-lens and a post-lens fraction, creating two substantial structural and functional modifications: the disappearance of mucine in the pre-lens part and the loss of the lipid layer in the post-lens part. This fact has been evaluated and proven by interpherometry investigations 28. Contact lens wear compromises the precorneal film stability and causes the disappearance of the lipid layer in the post-lens fraction which is responsible for the tear film stability. Furthermore this separation of tear film triggers an increase of water evaporation 29 followed by a corresponding increase of the tear osmolarity and consequently resulting in ocular surface damage 11,30,31. This mechanism which links modifications in lipid layer with a consequent tear film instability as well as increased water evaporation could also explain the strong positive correlation that was obtained in our investigation between TBUT and Schirmer II values (r=0.74). During long time wearing of contacts these changes become more pronounced and the effect of contact lens precorneal position is accumulated over time which manifests as a stronger feeling of discomfort consequently meaning a higher OSDI score. We hypothesise that other mechanisms other than tear film separation, like the changes in corneal epithelium and/or cytokine production, could also contribute to the worse TBUT and OSDI values in long term wearers. It should be emphasized that our investigation was conducted as a pilot study with a smaller number of participants. Nevertheless, motivating results were obtained especially considering the small number of publications that addressed differences in symptoms and signs of dry eye in RGP and soft lens wearers in the last few decades. We hope that this study will encourage researchers to conduct larger scale investigations on dry eye related problems in RGP and soft lens wearers in the future. The presented correlations, although in most cases weak or moderate, show trends that could assist in advising, monitoring and ultimately the treatment of contact lens wearers. which affects a large number of contact lens wearers today. REFERENCES 1. 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5 G. Eur J Epidemiol, 16 (2000) NICHOLS JJ, KING-SMITH PE. Investigative Ophthalmology &Visual Science, 44 (2003) DOUGHTY MJ. Contact Lens and Anterior Eye, 22 (1999) STAHL U, WILLCOX M, STAPLETON F. Clin Exp Optom, 95 (2012) FOULKS GN, Surv Ophthalmol, 52 (2007) 369. S. Ka{telan Department of Ophthalmology, University Hospital Dubrava, Avenija Gojka [u{ka 6, Zagreb, Croatia. snjezanakastelan@yahoo.com SIMPTOMI I ZNAKOVI SUHOG OKA U DUGOTRAJNIH NOSITELJA KONTAKTNIH LE]A SA@ETAK Cilj istra`ivanja bila je analiza povezanosti subjektivnih samostalno prijavljenih simptoma i objektivnih znakova suhog oka u dugotrajnih nositelja tvrdih plinopropusnih i nositelja mekih kontaktnih le}a. U istra`ivanje su bila uklju- ~ena 32 oka pripadnika bijele rase starosti od 21 do 42 godine koji su neprekidno svakodnevno nosili tvrde plinopropusne i meke kontaktne le}a tijekom 2 i vi{e godina. Procjena subjektivnih simptoma vr{ena je pomo}u upitnika Ocular Surface Disease Index (OSDI) dok je klini~ka procjena uklju~ivala je bojenje ro`nice fluoresceinom, tear film break-up time (TBUT) test i Schirmer II test. U istra`ivanje je bilo uklju~eno vi{e mu{karaca (62,5%) nego `ena (37,5%) s ve}im udjelom nositelja tvrdih plinopropusnih kontaktnih le}a me u mu{karcima (40% vs 17%). Prosje~no trajanje dnevong no{enja kontaktnih le}a bilo je 10,6±5,37 sati sa statisti~ki zna~ajno ve}im udjelom bolesnika s produ`enim dugotrajnim no{enjem le}a u skupini nositelja mekih kontaktnih le}a (p<0,05). Me u `enama i nositeljima mekih kontaktnih le}a uo~en je ve}i udio samoprijavljenih blagih i umjerenih znakova suhog oka. Niti jednom nositelju tvrdih plinopropusnih le}a u ovom istra`ivanju povr{ina ro`nice nije se zna~ajnije bojala fluoresceinom te imala vrijednost ve}u od 2 prema sustavu vrednovanja Ameri~kog nacionalnog o~nog instituta (NEI). Utvr ena je umjerena negativna korelacija izme u duljine dnevnog trajanja no{enja kontaktnih le}a i TBUT-a (Pearson-ov koeficijent, r= 0,47) kao i vrijednosti Schirmer testa II te vi{eg OSDI zbroja odnosno blagih i umjerenih kategorija suhog oka (r= 0,50). Izme u vrijednosti TBUT-a i Schirmer II testa na ena je jaka izra`ena pozitivna korelacija (r=0,74). Rezultati istra`ivanja upu}uju na va`nost rane i to~ne dijagnoze suhog oka s ciljem uspje{nog dugotrajnog no{enja tvrdih plinopropusnih kao i mekih kontaktnih le}a {to biti daljnji poticaj za provo enje istra`ivanja ve}ih razmjera vezanih za problem suhog oka i no{enja kontaktnih le}a. 203