Abstract
Purpose :
Stereopsis is the hallmark of binocular vision but is generally believed to be unachievable in patients who undergo treatment for unilateral congenital cataracts. We have demonstrated some level of stereopsis at age 4½ in our study and have reevaluated this population at age 10½.
Methods :
Infants between the ages of 4 weeks and 7 months with a visually significant unilateral cataract were randomly assigned to be left aphakic or have an IOL implanted at the time of the initial cataract extraction. A total of 114 infants were enrolled in the study between December 23, 2004 and January 16, 2009 at 12 clinical sites. Patients were followed on a regular basis until age 5 years. One additional assessment was obtained at age 10½ to measure long-term outcomes after the sensitive period for visual development.
The Randot Preschool Stereotest was used at age 4½ by a traveling tester and at age 10½ by a study certified tester at each site. Monocular visual acuity at age 10½ was evaluated using the E-ETDRS protocol.
Results :
Only 11 of the 107 patients tested on the Preschool Randot at age 10½ demonstrated some level of stereopsis, defined as identifying at least two of the three images viewed through polarizing lenses. E-ETDRS visual acuity in the treated eyes for these patients varied from 20/40 or better to 20/200 or worse (Table 1). Six of the original 114 did not provide VA data at age 10½ and one patient had been lost to follow-up before the 4½ year testing, hence the total number for this report was limited to 107.
Comparing stereopsis measures between the two ages indicated that only three of the patients who had demonstrated stereopsis on this test at age 4½ also showed stereopsis at the later age (Table 2). It should be noted that all three of the individuals who had positive findings at both ages had E-ETDRS VA of 20/40 or better (Kappa = 0.473 (95% CI 0.12,0.83)).
Conclusions :
These findings demonstrate that, while rare, it is possible for patients with unilateral congenital cataracts to achieve some degree of stereopsis measured by randot stimuli. However, the static nature of these tests may under-represent the extent to which an individual uses both eyes together in the real world.
This is a 2020 ARVO Annual Meeting abstract.