Quantitative Assessment of Outer Retinal Layer and Photoreceptor Outer Segment Layer and Their Relation to Visual Acuity in Diabetic Macular Edema.

Ahmed Hosni Abd Elhamid

doi:10.1155/2019/8216150

Abstract

Purpose To compare outer retinal layer (ORL) thickness and photoreceptor outer segment (PROS) length between normal eyes and eyes with diabetic macular edema (DME), and also, to study the correlation between central macular thicknesses (CMT), ORL, and PROS length with best corrected visual acuity (BCVA) in DME. Methods 80 eyes were included in the study; they were divided into two groups, group Ι (40 normal eyes) and group ΙΙ (40 eyes) with DME. Complete ophthalmic examination and OCT were done for all eyes. Comparison between ORL and PROS was done between both groups; also, correlation between ORL thickness, PROS length, and CMT with BCVA in group ΙΙ was studied. Results CMT was greater in group ΙΙ than group Ι (392.70 ± 62.91 and 265.73 ± 17.17, respectively) (SS, p < 0.001). ORL thickness was statistically significantly greater in group Ι than group ΙΙ (104.80 ± 4.94, 93.68 ± 6.34, p < 0.001). Regarding PROS length, it was statistically significantly greater in group Ι than group ΙΙ (31.38 ± 3.4 and 26.65 ± 3.39, respectively, p < 0.001). There was moderate correlation between BCVA and ORL thickness (r = −0.440, p=0.004) and strong correlation between BCVA and PROS length in group ΙΙ (r = − 0.690, p < 0.001), while there was weak correlation between BCVA and CMT (r = 0.198, p=0.220). Conclusion Both ORL thickness and PROS length were greater in healthy normal eyes than eyes with DME. BCVA was correlated better with PROS length and ORL thickness than CMT.

Highlights

Diabetic macular edema (DME) is a leading cause of visual loss [1]
In patients with DME, best corrected visual acuity (BCVA) was found to vary according to photoreceptor outer segment (PROS) thickness, when this thickness was measured at the center of the fovea [8]. e integrity of the inner segment/outer segment junction (IS/OS) junction has been found to correlate well with visual acuity in subjects with retinal diseases such as retinitis pigmentosa and postmacular hole surgery [3]
Exclusion criteria are significant media opacity that can lead to poor quality and signal of the Optical coherence tomography (OCT) image; other conditions that are excluded from group ΙΙ are neurosensory detachment, previous laser treatment, subfoveal exudates, and disrupted external limiting membrane (ELM) or IS\OS junction

Summary

Introduction

Diabetic macular edema (DME) is a leading cause of visual loss [1]. Pathological retinal abnormalities in patients with diabetic retinopathy are subject for research and clinical studies since long time [2].Optical coherence tomography (OCT) is a reliable noncontact and noninvasive diagnostic tool used in many retinal disorders including DME. Diabetic macular edema (DME) is a leading cause of visual loss [1]. Pathological retinal abnormalities in patients with diabetic retinopathy are subject for research and clinical studies since long time [2]. Many studies showed contradicting correlation between the measured CMT and best corrected visual acuity (BCVA) in DME [4,5,6,7]. In patients with diabetes and no retinopathy, the photoreceptor cell layer at the fovea was found to be thinner than the corresponding layer in healthy volunteers. In patients with DME, BCVA was found to vary according to PROS thickness, when this thickness was measured at the center of the fovea [8]. In patients with DME, BCVA was found to vary according to PROS thickness, when this thickness was measured at the center of the fovea [8]. e integrity of the IS/OS junction has been found to correlate well with visual acuity in subjects with retinal diseases such as retinitis pigmentosa and postmacular hole surgery [3]

Methods

Results

Conclusion