Abstract
Purpose: :
To evaluate the correlation between the findings of spectral domain OCT (SD-OCT) and histopathology of the primate retina after exposure of light emitted diode (LED).
Methods: :
Under general anesthesia, the right eyes of 3 male monkeys (Body weight 5-10kg) were exposed to white LED light (8912cd) which is embedded in contact lens for 8 hours. SD-OCT was performed to the exposed eyes and control eyes immediately after and at post-exposure days 1 and 14. The eyes were enucleated at 12 hours after light exposure and subjected to electron and light microscopy. We evaluated OCT images and histological sections before and after light exposure. TUNEL staining was performed.
Results: :
Immediately after LED exposure, because the zone between photoreceptor inner and outer segment junction (IS/OS) and retinal pigment epithelium (RPE) was hyper reflective, IS/OS and RPE were hardly separated into distinct two lines. On post exposure day 1, the two hyper-reflective lines were fused in the perifoveal but they were separated at the central fovea. On post-exposure day 14, IS/OS line and RPE were shown as distinct two lines which comparable to OCT finding of normal control. In light microscopic sections at 12 hours after LED, photoreceptor outer segment (OS) was partially shorten and misaligned while inner segment (IS) appeared normal. Electron microscopy revealed disruption of intracellular lamellar organelles in OS but IS appeared normal. There were no apparent TUNEL positive cells in both control and exposed retina.
Conclusions: :
Light exposure to the retina caused disruption of intracellular structure in photoreceptor OS which presented as ill-separated IS/OS and RPE on SD-OCT. Photoreceptor IS and its nucleus appeared intact.
Keywords: photoreceptors • pathology: experimental • imaging/image analysis: non-clinical