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Purpose:
The age at onset of retinal degeneration in Usher Syndrome type 2A (USH2A) remains unclear. We studied OCT findings in asymptomatic USH2A children with otherwise normal ocular exams.
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Methods:
We retrospectively reviewed the charts of five children, under IRB approved protocol with a molecularly confirmed diagnosis of USH2A and no signs of retinopathy. Best corrected visual acuity (BCVA), OCT, and full-field electroretinography (ffERG) were obtained as standard of care. On OCTs, we scored predetermined atypical findings and used the 'plot profile' plugin of ImageJ (NIH, Bethesda, MD) to determine reflectivity values of the retinal pigment epithelium (RPE), ellipsoid zone (EZ), and external limiting membrane (ELM).
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Results:
Five children (3 females, 2 males), median age 8 years (range 6–10). At presentation, BCVA ranged from 20/20 to 20/30, with normal ff-ERG and OCT in all subjects. At the last follow-up, BCVA remained 20/20 in 4/5 subjects. OCT findings remained normal in 3/5 subjects ages (6-8). However, two subjects, aged 9, showed attenuation of the EZ-band at the perifovea on OCT scans, this was observed one-year before the development of ff-ERG changes. Among the three subjects with abnormal ff-ERG results, two were the ones with prior OCT changes, while the third, a 7-year-old, exhibited abnormal ff-ERG findings since age 4 but maintained normal OCT scans throughout the follow-up period. Reflectivity profile analysis confirmed these findings, indicating decreased reflectance in the EZ, ELM, and RPE respectively.
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Conclusions:
Our study shows OCT may detect early retinal changes before ff-ERG abnormalities in some USH2A patients.