Abstract
Purpose::
Trisomy 21 Downs syndrome is known to be associated with a significant prevalence of ocular diseases that often are undetected or untreated. A complete ocular examination was provided the Downs children participating in the European Special Olympics during which the prevalence of ocular disease was evaluated as well as the sensitivity and specificity for detection by the screening vision tests LEA chart and Central Vision Screener (CVS, Vimetrics).
Methods::
91 athletes participated in the ocular evaluation during which the following were performed: LEA Symbol ETDRS chart visual acuity with habitual correction, refraction, Ishihara plate color vision, Random dot E stereopsis, IOP, pupil reactivity, anterior segment slit lamp and 90D lens fundus exam without dilation. The vision of each eye was also tested with the CVS, an interactive computer program that presents tumbled Landolt Cs under different photopic and mesopic environments and thresholds for the smallest C correctly discriminated.
Results::
91 Downs athletes participated with a mean age of 24.6 (9-47). The following abnormalities were detected: 14 eyes with significant uncorrected refractive error, 4 high myopia, 2 strabismus, 32 stereopsis or color abnormalities, 6 significant cataract, 9 significant macular disease. In evaluation of the LEA chart acuity or CVS1000 as a screening test, an abnormal test was considered for an acuity of ≤ 20/50. A referral was designated when an eye failed at least one or more of the above tests. When the LEA test was evaluated as a screening test, in 38 eyes an acuity could not be obtained, 32 of which needed referral. Among the 50 in whom the LEA VA was ≤ 20/50, the sensitivity was 0.81 and specificity 0.357 for detecting disease. The CVS could not be performed in 40 eyes and in 40 eyes all module results were poor, all with detected disease. In 98 eyes at least one of the 6 CVS modules was completed with reliable results. When an abnormal test ( ≤20/50) was obtained for any module the sensitivity varied from 0.83 to 0.58 and the specificity from 0.65 to 0.50.
Conclusions::
A significant prevalence of ocular disease was observed in this population of Downs young adults, most previously unknown or untreated. Screening with the CVS appeared slightly better in the indication of the need for referral than the ETDRS LEA symbol chart although both had reasonable sensitivity and specificity. Further evaluation is required with other chart methods or test devices to define one or a combination that optimize screening of such a difficult but necessary population with a high prevalence of ocular undetected and untreated disease.
Keywords: visual acuity • contrast sensitivity • contrast sensitivity