Abstract
Purpose: :
Down syndrome is the most commonly identified genetic form of developmental disability with an estimated incidence of 1:600 live births in Brazil. Cataract occurs in 1.5-20% of Down syndrome cases, mainly bilaterally, leading to severe visual impairment if not treated. The purpose of this study is to investigate grating acuity outcomes in children with Down Syndrome undergoing cataract extraction.
Methods: :
Best-corrected grating acuity (BCGA) was measured electrophysiologically by sweep visual evoked potential (sweep-VEP) technique from each eye in 13 patients with Down Syndrome (age 6 months - 10 years; 6 females) who had been operated for bilateral cataracts (11 aphakic - 22 eyes, 2 pseudophakic - 3 eyes). An additional group of 10 patients with Down Syndrome and absence of cataract in each eye was also tested (age 2 months - 12 yrs; 3 females). Acuity deficits from mean normal were calculated based on age norms from our own lab. Amblyopia was diagnosed when interocular acuity difference > 0.1 logMAR was detected.
Results: :
Age at surgery ranged from 1.5 to 60 months of age (mean=13.4±12.9; median=9). BCGA was measured within 3 months - 8 years after surgery (mean=24.3±33.6 mos.; median=7.2 mos). In cataract-operated patients, BCGA deficits were present in all eyes (0.13 - 1.36 logMAR; mean=0.61±0.31; median=0.50), with amblyopia in 7 (53.8%) patients. Patients with Down Syndrome without cataract showed BCGA deficit in 13(65.0%) eyes (0.08 - 0.79 logMAR; mean=0.37±0.25; median=0.27) and none had amblyopia. Greater acuity deficits were found in cataract-operated eyes compared with eyes from patients with Down Syndrome and no cataract (Mann-Whitney rank sum test, P=0.023).
Conclusions: :
Post-operative grating acuity outcomes in Down syndrome patients with bilateral cataracts disclosed substantial deficits as well as high frequency of amblyopia. Better acuity outcomes could probably be achieved with earlier diagnosis and surgical treatment, providing improved visual function and quality of life for these patients.
Keywords: amblyopia • visual development: infancy and childhood • visual acuity