Purpose:
Although various Optical Coherence Tomography (OCT) studies have examined the architecture of the albino retina, thus far, none of them have focused on the Retinal Pigmented Epithelium (RPE) layer. We describe the structure of the RPE layer in patients affected by albinism by means of high-resolution, spectral-domain OCT.
Methods:
High-resolution spectral domain OCT (SOCT Copernicus, 3 µm, B scan acquisition time 23ms) was used to image retinae in 24 patients and 20 healthy volunteers, scanning each eye at least 3 times. Three of the albino eyes had to be excluded due to poor image quality. B scans were flattened along the RPE layer and a reflectance profile at the fovea was generated using ImageJ software, averaging 3 profiles from each eye. The graphs were then scored for the presence of peaks and troughs in the RPE region and amplitude measurements were estimated using Spike 2 software.
Results:
Analysis of the RPE layer revealed 3 peaks in 72.7% of the albino eyes compared to 10.0% in the control group. A distinct deep trough (T1 - see figure) was also evident between the first and second peak in albinos. Quantification of the trough amplitude showed that T1 was significantly larger (p<0.0001) in albinos (30.8%, SD16.5 of RPE peak) compared to controls (10.0%, SD3.94 of RPE peak).
Conclusions:
Using high resolution spectral domain OCT, we have been able to determine subtle differences in the RPE layer of the albino retina compared to normal healthy retina for the first time. Being able to characterize these differences will lead to a greater understanding of the pathophysiology of visual defects associated with albinism and assist in the accurate diagnosis of albinism.
Keywords: retinal pigment epithelium • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)