How Often Are Spectacles Prescribed to Normal Preschool Children?

Transcription

1 How Often Are Spectacles Prescribed to Normal Preschool Children? Sean P. Donahue, MD, PhD Introduction: Legislation to require formal eye examination prior to school entry is being considered in several states and is supported by optical trade organizations. Pediatric ophthalmologists cite anecdotal cases that suggest children receive spectacles unnecessarily, but data to support this are lacking. Methods: Eye examination results from children referred to local eye doctors following a statewide preschool photoscreening program were reviewed to determine how often glasses were prescribed for children who did not have amblyogenic factors (those with false-positive screenings). Results: Of 102,508 preschool children screened, 890 children did not have amblyogenic factors (false-positive screenings). Nevertheless, spectacles were prescribed for 174 (19.5%) of these children. Only 5/272 children (1.8%) were prescribed glasses following examination by a pediatric ophthalmologist, while glasses were prescribed for 24/205 children (11.7%) examined by comprehensive ophthalmologists and 145/413 (35.1%) of children seen by optometrists (P 0.001). Eighty children were prescribed glasses for refractive error ranging from 0.75 sph to 2.00 sph, 32 of whom had spherical equivalent of 1D or less. Conclusions: While some preschoolers without amblyogenic factors may require spectacle correction, a significant percentage of children are probably prescribed glasses unnecessarily. Extrapolation of these data to the United States population suggests that a single mandatory eye examination prior to school entry could cost over $200,000,000 yearly for unnecessary spectacles. Vision screening programs with high referral rates, and health policy proposals supporting comprehensive preschool eye exams, must consider these unnecessary costs. (J AAPOS 2004;8: ) A mblyopia is a significant public health problem. It is the leading cause of monocular blindness in the United States 1 and is associated with an increased likelihood of vision loss in the fellow eye. 2,3 Preschool vision screening is advocated to detect amblyopia and provide early treatment. Techniques of preschool vision screening vary, but all recommend prompt referral for confirmation and initiation of treatment. Effective vision screening programs need to be sensitive and specific, without overlooking abnormalities, while at the same time not causing significant false-positive overreferral. While parents are often relieved that their child does not have a vision problem, many such parents are upset because of the time involved that is taken from other activities (school and work), and because medical insurance often will not cover the examination costs because no From the Tennessee Lions Eye Center at Vanderbilt Children s Hospital, Departments of Ophthalmology, Pediatrics, and Neurology at Vanderbilt University Medical Center, Nashville, TN. Support in part by a Research to Prevent Blindness Career Development Award (SPD) Tennessee Lions Charities, Lions Clubs International Foundation, State of Tennessee. Submitted March 9, Revision accepted May 14, Reprint requests to: Sean P. Donahue, MD, PhD, Ophthalmology and Visual Sciences, Vanderbilt University, st Avenue South, 104 Medical Arts Building, Nashville, Tennessee ( sean.donahue@vanderbilt.edu) Copyright 2004 by the American Association for Pediatric Ophthalmology and Strabismus /2004/$ doi: /j.jaapos pathology is identified. Examining doctors also become frustrated when vision screening programs with low specificity produce large numbers of patients without problems (high false-positive rate). In addition to the above direct and indirect costs, another associated, but often overlooked, problem can also follow overreferral. This problem is exemplified by the child who presents for a second opinion following an examination for a failed vision screening because the child won t wear his glasses. The child has normal uncorrected acuity, mild-to-moderate hypermetropic cycloplegic refractive error and is otherwise normal, but has been prescribed spectacles. The spectacles typically have only mild hypermetropic correction. These children and their parents often only need reassurance and a suggestion to discontinue the spectacles. Many eye doctors relate this anecdotally, but prevalence data, and the direct and indirect costs of unnecessary spectacle correction following overreferral, remain unknown. The Tennessee Lions Statewide Preschool Vision Screening Program began in Since that time, detailed records have been maintained for all children screened, and follow-up data from formal comprehensive eye examinations of referred children have been recorded in a specially designed database. Querying this very large database provides a unique opportunity to observe how children are managed following vision screening. In this study, we reviewed the postexamination management of 224 June 2004 Journal of AAPOS

2 Journal of AAPOS Volume 8 Number 3 June 2004 Donahue 225 TABLE 1. Criteria to fail eye examination 1. Anisometropia (cylindrical or spherical) 1.00 diopter (D) 2. Any manifest strabismus 3. Hyperopia 3.50 in any meridian 4. Myopia 3.00 in any meridian 5. Any media opacity 1mm 6. Astigmatism: 1.5Dat90or at oblique axis (more than 10 from 90 or 180) patients who were referred following preschool vision screening but did not have amblyogenic factors on formal comprehensive ocular examination to determine how often spectacles are prescribed following such false-positive screenings. METHODS The Tennessee Lions Outreach Program uses the MTI photoscreener (Riviera Beach, FL) to evaluate children for amblyogenic factors. The process has been reported in detail elsewhere. 4,5,6 Briefly, volunteers from local Lions Clubs photoscreen children in daycare centers, preschools, and mother s day out centers. The photographs are interpreted centrally (Vanderbilt Ophthalmic Imaging Center) using preestablished referral criteria, designed to have a low sensitivity, but high specificity (low false-positive rate). 4,6 Children are between the ages of 12 and 71 months (1 to 5 years). Children who are referred receive a list of ophthalmologists and optometrists in their area who are willing to perform an examination. The results of this examination are sent to the coordinating center. Results of each child s screening are incorporated into a specially designed database. For referred children, follow-up data, including visual acuity, cycloplegic refractive error data, and whether or not glasses were prescribed, are recorded. We queried the database to identify referred children who did not have amblyogenic factors (see Table 1) found upon formal eye examination. These children, who were considered to have had false-positive screenings, had their examination data reviewed further. They were placed into two groups based upon their refractive error. Patients with essentially no refractive error (anisometropia 0.75D, hypermetropia 2.00D, myopia 0.75D, and astigmatism 0.75D) constituted the first category (Group A). A second group, consisting of children having refractive error too great to be in Group A but still less than factors determined to be amblyogenic (Table 1), were placed into a second category (Group B). Data were evaluated based on whether or not glasses were prescribed, the level of refractive error, and the training of the eye doctor performing the examination. In an attempt to separate examinations done by doctors who had more experience with children, we separated the results from doctors who had examined at least five children having false-positive examinations ( experienced doctors ) from those who saw fewer than five children with falsepositive examinations. Our program currently has a Positive Predictive Value of 74%, so five false-positive examinations correspond to approximately 20 children being referred and examined. Statistical calculations were performed using Fisher s exact test, 2, and paired t test, as appropriate. P 0.05 was needed for statistical significance. RESULTS From the beginning of the program (June 1997) until April 30, 2003, 102,508 children were photoscreened. The dates of screening may seem remote but this provided 6 months for follow-up examinations to occur. Ninety-seven percent of the children completed the screening, and 4.7% were referred. Referred children were examined by local optometrists and ophthalmologists. During this period, the overall follow-up rate was 74.8%. Of the 3640 referred children who were examined, 890 (24.5%) had adequate follow-up examinations, but did not have any amblyogenic factors, nor any notation from the examining doctor about pathology. These children were considered to have had false-positive examinations. Of the 890 false-positive examinations, 413(46.4%) were performed by 186 optometrists; 205 (23.0%) were performed by 78 comprehensive ophthalmologists, and 272 (30.6%) were performed by 11 pediatric ophthalmologists (Table 2). A total of 275 doctors was involved. Four hundred ninety-five of these children (55.6%) were examined by doctors who performed at least five false-positive examinations (39 experienced doctors, typically 20 overall examinations). Of these doctors, 20 optometrists examined 147 children (29.7%); 12 comprehensive ophthalmologists examined 86 children (17.4%), and seven pediatric ophthalmologists examined 262 children (52.9%) (Table 2). One hundred seventy-four of the 890 children without amblyogenic factors were prescribed glasses (prescribing rate of 19.6%). The spherical equivalent refractive error for the prescribed spectacles is shown in Table 3. Of the 174 children prescribed glasses, 8 had myopia that was at least 1D but less than the 3D of myopia considered to be an amblyogenic factor. Thirty-two children were prescribed spectacles for a refractive error of 1D spherical equivalent refractive error, while 106 with hypermetropic refractive error spherical equivalent between 1.00 and 3.00D received glasses. Twenty-eight children who had refractive error ranging from 3.00 to 3.50D were prescribed spectacles. None of these children had strabismus or any other reported pathology. Optometrists prescribed spectacles more often than did pediatric ophthalmologists or comprehensive ophthalmologists (Table 4). Only 5 of 272 children (1.8%) who did not have amblyogenic factors and who were seen by pediatric ophthalmologists were prescribed spectacles, compared to 24/205 (11.7%) children examined by general ophthalmologists and 145/413(35.1%) children seen by optometrists ( ; P 0.001).

3 226 Donahue Journal of AAPOS Volume 8 Number 3 June 2004 TABLE 2. Summary data regarding false positive examinations Examination by Number of Doctors Number of Examinations Fewer than 5 False- Positive Exams* 5 or More False-Positive Exams Doctors Exams Doctors Exams Optometrist (46.4%) (67.3%) (29.7%) Comprehensive Ophthalmologist (23.0%) (30.1%) (17.4%) Pediatric Ophthalmologist (30.6%) 4 10 (2.5%) (52.9%) Total *Most doctors saw only a few normal children. TABLE 3. Spherical equivalent refractive error for children without amblyogenic factors who were prescribed glasses Myopia Spherical Equivalent Refractive Error Hyperopia Type of Doctor >1D 0-<1D 0-1D >1-2D >2-3D >3-3.50D Total Optometrist Comprehensive Ophthalmologist Pediatric Ophthalmologist Total TABLE 4. Frequency of prescribing glasses in the absence of refractive or other pathology Type of Doctor Number of Examinations Glasses Given Percentage Optometrist % Comprehensive Ophthalmologist % Pediatric Ophthalmologist % Total % TABLE 5. Refractive error of four patients prescribed spectacles by experienced pediatric ophthalmologists O.U. 2. OD: 3.50 sph; OS: 3.00 sph 3. OD: 2.00 sph (VA 20/30); OS: 3.00 sph (VA 20/60) 4. OD: ; OS: In an attempt to determine if doctors who were more familiar examining children had different prescribing requirements, we evaluated the prescribing behavior of the experienced doctors. These 39 represented only 14.2% of the 275 doctors who saw children for this project. They performed 495 of the 890 (55.6%) examinations, but prescribed only 66 of the 174 spectacles (38%), for a prescribing rate of 13.3%. This was compared to 108 prescriptions in 395 (27.3%) examinations done by less-experienced doctors (P 0.02 for difference in prescribing frequency). However, this difference occurred because the experienced doctor group had a higher proportion of pediatric ophthalmologists. When level of training was included as a variable, however, there was no difference between the experienced and less-experienced doctors with respect to prescribing behavior: 36.1 vs. 34.6% for optometrists (P NS); 10.5 vs. 12.6% for comprehensive ophthalmologists (P NS); 1.5 vs. 10% (1/10) for pediatric ophthalmologists (P NS). Experienced pediatric ophthalmologists prescribed spectacles for only four children without amblyogenic factors. The refractive errors and visual acuity for the four patients, who were prescribed spectacles by pediatric ophthalmologists in the absence of amblyogenic factors, are given in Table 5. To determine if level of training impacted the refractive error at which spectacles were prescribed, we divided children into two groups (Table 6): those who had no significant refractive error (hypermetropia 2.00D, myopia 0.75D, astigmatism 0.75, or anisometropia 0.75D, Group A) and those who may have had some rationale for spectacles (Group B). We did this for both the experienced and the less-experienced doctors. Overall, 43of the 174 (24.7%) children who received a glasses prescription were in Group A. The percentage of children in Group A compared to the total number seen was similar for optometrists, ophthalmologists, and pediatric ophthalmologists. However, a bias could have been present if children with low refractive error were more likely to present to doctors of a certain type. The large number of doctors and relatively small number of patients seen per doctor made a global analysis of this impossible. However, we were able to evaluate this more robustly for the smaller group of 39 experienced doctors who performed 495 of the examinations (Table 6). Of the 495 children who were examined by the experienced doctors, 263(53.1%) had refractive error in Group A, while 232 (46.9%) had refractive error in Group B. Of the 263children with essentially no refractive error (Group A), 6.1% received spectacles. The percentage of children in Group A who were prescribed glasses was greater if they had been seen by optometrists (18.1%) than if they had been seen by comprehensive (2.3%) or pediatric ophthalmologists (0%) ( ; P 0.01).

4 Journal of AAPOS Volume 8 Number 3 June 2004 Donahue 227 TABLE 6. Spectacle data for children without amblyogenic factors who were given spectacles Type of Doctor Group A (no refractive error) All Doctors Group B (minimal refractive error) Total Group A (53%) (no refractive error)** Experienced Doctors Group B (47%) (minimal refractive error)*** Optometrist /83 (18%) 38/64 (59%) 53/147 Comprehensive Ophthalmologist /43 (2%) 8/43 (19%) 9/86 Pediatric Ophthalmologist /137 (0%) 4/125 (3%) 4/262 Total /263 (6.1%) 50/232 (21.6%) 66/495 *See Results. **P ***P Total FIG 1. Results from examination of children found not to have amblyogenic factors or other pathology. Each point represents the frequency with which a given doctor prescribed spectacles. Only doctors who performed at least five examinations on children without amblyogenic factors are included (n 39). Of the 232 children in Group B (refractive errors not amblyogenic), 21.6% received spectacles. The percentage was again greater for children seen by optometrists (59.4%) than comprehensive (18.6%) or pediatric (3.2%) ophthalmologists ( ; P 0.001). There was marked variability among individual providers in the frequency with which glasses were prescribed when only experienced doctors were considered (Groups A and B combined, Figure 1). For optometrists, the percentage ranged from 0% (0/5) to 80% (4/5), including one doctor who prescribed for 8 of 13normal children. For comprehensive ophthalmologists, the percentage ranged from 0 to 40%. None of the seven pediatric ophthalmologists who had five or more falsepositive examinations had a prescribing rate exceeding 3%.

5 228 Donahue Journal of AAPOS Volume 8 Number 3 June 2004 In an attempt to determine the overall cost to society for unnecessary spectacles, we assumed that 5,000,000 children are born (or enter kindergarten) each year, that spectacles cost a minimum of $150, that the baseline rate of spectacle dispensing for children without amblyogenic factors is 1.8% (5/272 seen by pediatric ophthalmologists), but that 19.6% (174/890) preschool children receive glasses when they are seen but do not have amblyogenic factors. Thus, 18% of normal children will receive unnecessary spectacles, at a cost to society of $135,000,000/year, if they receive a typical examination. If most examinations are performed primarily by optometrists and comprehensive ophthalmologists, the unnecessary spectacle rate could be as high as 27.3% (169/618), and the annual cost as much as $200,000,000 ( ,000,000 $150). DISCUSSION All methods of vision screening, including comprehensive eye examinations, have a sensitivity and a specificity to detect pathology. Increasing the sensitivity of any test results in an increase in the false-positive rate and a corresponding increase in referrals. Decreasing the referral rate to reduce overreferrals causes a decreased sensitivity as fewer abnormal children are referred. Preschool vision screening typically seeks to detect amblyopia and strabismus and high refractive error. Most eye doctors are able to report anecdotal experiences of visually normal children who are wearing glasses, although they have no significant refractive error. The prevalence of this phenomenon is unknown. In this study, we attempted to determine how often glasses are prescribed for normal children. We found that nearly 20% of normal children receive a prescription for glasses following a visit to an eye doctor, despite not having an amblyogenic factor or other pathology. We also found that spectacles are often prescribed for children having 1D of refractive error and that spectacle-prescribing behavior, while varying widely among individual doctors, did not change for doctors seeing a high volume of children. This study also showed that pediatric ophthalmologists were much less likely to prescribe spectacles in such situations. A surprising percentage of children (6.1%) received glasses for refractive error that would not be symptomatic in healthy preschool children (Group A) (Table 6). There are four sets of guidelines available to assist the eye care practitioner in prescribing spectacles for preschool children. The American Academy of Ophthalmology s Preferred Practice Patterns for the comprehensive pediatric eye examination 7 and the diagnosis and treatment of amblyopia 8 lists guidelines for prescribing for refractive error in children up to age 4 years. For children aged 3and under, they suggest prescribing spectacles for 4.50D or more of hypermetropia. The focal points module by Spencer is even more restrictive. 9 Survey data from Miller and Harvey 10 suggest that 25% of pediatric ophthalmologists prescribed spectacles for 4D of hypermetropia in children up to 4 years of age, while 25% prescribed for 3.00 to 3.50 in children aged 5 to 7 years. The recently released American Association for Pediatric Ophthalmology and Strabismus standards for detection of ocular pathology during preschool vision screening 11 is the least stringent and suggests hypermetropia 3.50 be detected by screening instruments. We applied the least stringent of these standards to our data to determine the impact of overreferral from preschool vision screening programs and found that up to 20% of children with refractive error less than this standard will receive spectacles. Optometrists and comprehensive ophthalmologists may be more likely to prescribe glasses, if they apply adult standards to children. We did not determine whether the presence of an optical dispensary in the doctor s office played a role in spectacle prescribing. These data may overestimate the rate at which glasses are unnecessarily prescribed. Children referred from photoscreening are likely to have a higher refractive error than the general population, since the largest determinant in crescent size during photoscreening is refractive error. Our results showed that children with low refractive error were less likely to have glasses prescribed than were those with mild-to-moderate refractive error. There may be other reasons for prescribing spectacles for children other than cycloplegic refractive error. The Preferred Pediatric Practice Pattern for the comprehensive pediatric eye examination suggests that, for children aged 4 years or older, glasses should be prescribed if visual acuity can be improved or if the patient has asthenopia. 7 Asthenopia in otherwise healthy 2- to 4-year-old children is uncommon. There does not appear to be any reason children who saw optometrists or comprehensive ophthalmologists would have had a higher prevalence of asthenopia or decreased acuity than those who are seen by pediatric ophthalmologists. It should be noted that all children in this study received cycloplegic refraction, as recommended by the American Academy of Ophthalmology Preferred Practice Pattern for the pediatric eye examination. 7 Nearly all optometrists in our program now routinely perform cycloplegic refraction, in contrast to the recent report by Kemper et al, 12 probably due to a large education commitment by this program for optometrists and ophthalmologists who see children. Preschool vision screening is recommended by the American Academy of Pediatrics. 13 Traditional vision screening is typical, but photoscreening is gaining acceptance. 14 Recent legislation has shifted emphasis from recommending screening be done by pediatricians, family doctors, and lay personnel, who do not have a vested interest in the outcome of the screening, to having screening replaced with an examination by an eye doctor, who may serve to benefit from the result. The validity, sensitivity, and specificity of such an approach has never been

6 Journal of AAPOS Volume 8 Number 3 June 2004 Donahue 229 studied. In addition, the cost effectiveness of such a mandate has never been proven. Nevertheless, legislation supporting mandatory preschool eye examinations has received widespread support, most recently from the Vision Council of America, which is the largest trade organization for optical manufacturers. Extrapolation of our results to the 5 million children who enter kindergarten each year demonstrates that such legislation would cost between $135 million and $200 million annually, simply for spectacles that are unnecessary as determined by the American Academy of Ophthalmology s Preferred Practice Pattern 7,8 and other guidelines regarding prescribing glasses for children. 9,10 Many preschool vision screening methods have been proposed. The prospective Vision in Preschoolers Study 15 will be the largest such study to evaluate the efficacy of traditional vision screening techniques and new vision screening methodology. The outcome measures for such vision screening methods will include usability, sensitivity, specificity, and predictive value. Our results suggest that the costs related to unnecessary prescribing of spectacles should be considered when the financial impact of methods for detecting amblyopia is assessed. References 1. Report on the National Eye Institute s Visual Acuity Impairment Survey Pilot Study. Bethesda, MD: Office of Biometry and Epidemiology, NEI, NIH, PHS, DHHS, Tommila V, Tarkkanen A. Incidence of loss of vision in the healthy eye in amblyopia. Br J Ophthalmol 1981;65: Rahi JS, Logan S, Timms C, et al. Risk, causes, and outcomes of visual impairment after loss of vision in the non-amblyopic eye: a population-based study. Lancet 2002;360: Donahue SP, Johnson TM, Leonard-Martin TC. Screening for amblyogenic factors using a volunteer lay network and the MTI PhotoScreener. Ophthalmology 2000;107: Donahue SP, Johnson TM. Age-based refinement of referral criteria for photoscreening. Ophthalmology 2001;108: Donahue SP, Johnson TM, Ottar W, Scott WE. Sensitivity of photoscreening to detect high-magnitude amblyogenic factors. J AAPOS 2002;6: Pediatric Eye Evaluations. Preferred Practice Pattern. San Francisco, CA: American Academy of Ophthalmology, Amblyopia. Preferred Practice Pattern. San Francisco, CA: American Academy of Ophthalmology, Spencer JB. A practical approach to refraction in children. American Academy of Ophthalmology Focal Points. San Francisco, CA: American Academy of Ophthalmology, 1989;11: Miller JM, Harvey EM. Spectacle prescribing recommendations of AAPOS members. J Pediatr Ophthalmol Strabismus 1998;34: Donahue SP, Arnold RW, Ruben JB, for the AAPOS Vision Screening Committee. Preschool Vision Screening: what should we be detecting and how should we report it? Uniform guidelines for reporting results of preschool vision screening studies. J AAPOS 2003;7: Kemper AR, Clark SJ, Freed GL. Services provided for preschoolaged children with suspected amblyopia. J Pediatr Ophthalmol Strabismus 2003;40: American Academy of Pediatrics Committee on Practice and Ambulatory Medicine, Section on Ophthalmology. Eye examination and vision screening in infants, children and young adults. Pediatrics 1996;98: Committee on Practice and Ambulatory Medicine and Section on Ophthalmology, American Academy of Pediatrics. Use of photoscreening for children s vision screening. Pediatrics 2002;109: Schmidt P, Maguire M, Dobson V, Quinn G, Ciner E, Cyert L, Kulp MT, Moore B, Orel-Bixler D, Redford M, Ying GS, Vision in Preschoolers Study Group. Comparison of preschool vision screening tests as administered licensed eye care professionals in the Vision In Preschoolers Study. Ophthalmology 2004;111: