Retinal Morphology Before and After the Treatment of Diabetic Retinopathy Evaluated With Spectral Domain Optical Coherence Tomography

Abstract

Purpose: : To demonstrate the spectral domain optical coherence tomography (SDOCT) patterns of diabetic retinopathy before and after treatment.

Methods: : Retrospective case series. Slit lamp biomicroscopy, color fundus photography and stratus OCT images were obtained in addition to images from a 5 um axial resolution prototype (SDOCT) which had an acquisition speed of approximately 26000 A-scans/second. Scans were obtained at the time of diagnosis and following treatment interventions such as intravitreal injections,laser and surgery. Some patients were scanned immediately after panretinal photocoagulation (PRP). Segmentation of ILM and RPE generated retinal thickness maps in 2D and 3D, which could be compared before and after treatment.

Results: : The study included 65 eyes of 45 patients, of whom 25 patients (35 eyes) had non-proliferative diabetic retinopathy (NPDR),and 20 patients (30 eyes) had proliferative diabetic retinopathy (PDR) of varying severities.Higher resolution and higher density SDOCT scans allowed for comprehensive improved visualization of the individual retinal layers.Hyperreflective epiretinal membranes were more evident in the SDOCT images than in stratus OCT.After surgery, the true retinal contour was clearly assessed from the images.In patients with diabetic macular edema,different patterns and locations of the fluid accumulation could be better studied with the SDOCT cross sectional scans and 3D thickness maps before and after treatment.After injections,some cases showed a decrease in the thickness and involution of the cystic spaces while other cases showed a development of larger cystic cavities which required repeated injections.Integrity of the photoreceptor layer could be better visualized with SDOCT,and was well correlated with the visual functioning before and after treatment.The acute changes in the spectral images after the PRP were the focal destruction and detachment of the retinal pigment epithelium focused at the periphery of the laser burns,disruption of the photoreceptors layer and an inflammatory reaction which was evident by increased thickness of the lasered area and accumulation of intraretinal exudates.

Conclusions: : The precise registration of SDOCT fundus images with the color fundus photographs detected subtle changes in retinal thickness and morphology before and after treatment for a better assessment of disease responsiveness.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • diabetic retinopathy • retina