Abstract
Purpose: :
To evaluate the spectrum of foveal architecture using high-speed, high-resolution SDOCT in pediatric ocular albinism. Because pediatric patient movement, either due to nystagmus or shortened attention span, limits time domain OCT imaging, SDOCT was used in this study.
Methods: :
SDOCT imaging was performed on both eyes of children in three groups: OA) with foveal hypoplasia and nystagmus on clinical exam but lacking some classic features of ocular albinism (5 subjects), OCA) with classic oculocutaneous albinism (1 subject) and NL) age and ethnicity matched normals (4 subjects). Ten by ten mm volumetric scans (containing 100 B-scans of 1000 A-scans each) were captured using standard and handheld SDOCT systems (Bioptigen Inc., Research Triangle Park, NC). The raw B-scan data were analyzed with ImageJ software (NIH; Bethesda,MD). The B-scan data were registered, cropped, and the outlier scans removed prior to data summation to yield a composite high-quality image of each subject’s fovea. Images were scored for presence or absence and configuration of each retinal layer across the fovea.
Results: :
Clinical exams of subjects showed: OA-- foveal hypoplasia, 20/40-20/60 acuity, nystagmus, light irides, and mild skin pigment; OCA-- foveal hypoplasia, 20/200 acuity, pale skin, and iris transillumination defects; NL-- 20/20 acuity and no nystagmus. Due to multiple rapid scan acquisition, we were able to capture high-quality images of all subjects, even those with notable nystagmus. Imaging revealed a variable range of abnormalities in foveal architecture of all eyes with OCA and OA when compared to NL. These included minor changes in the photoreceptor layer, high reflectivity across the fovea suggesting persisting nerve fiber layer, and presence of multiple inner retinal layers normally absent at the center of the fovea.
Conclusions: :
Rapid scanning capability of SDOCT allows more precise imaging even when faced with nystagmus. Persisting inner retinal layers on SDOCT imaging of OA and OCA defines the foveal hypoplasia seen clinically and could be the etiology of reduced acuity. Our SDOCT findings suggest that ocular albinism may represent a spectrum of foveal architectural changes. This imaging modality may be useful in evaluating OA suspects at a young age.
Keywords: imaging/image analysis: clinical • retinal development • visual development: infancy and childhood