Ganglion cell complex changes with long-standing diabetic macular oedema among Egyptian diabetic patients: an optical coherence tomography study

Abstract

Introduction Optical coherence tomography (OCT) is a valuable tool for imaging retinal thickness and structure as well as performing good evaluation for the ganglion cell complex (GCC) parameters, reflecting the status of retinal nerve fiber layer, the ganglion cell layer and the inner-plexiform layers. In this study, these parameters were evaluated in eyes with long-standing diabetic macular oedema, thus emphasising the importance of seriously treating macular oedema. Patients and methods Sixty eyes of 38 patients were included in the study. There were 38 eyes of 25 male patients and 22 eyes of 13 female patients. These 60 eyes were divided into two groups: group A (30 eyes) included eyes of patients with long-standing diabetic macular oedema (>1 year duration) and group B (30 eyes) included eyes of patients without apparent ocular pathology as a control. The age range was 23–73 years (mean 56.57±11.42) in group A and 30–74 years (mean 53.33±12.10) in group B. The duration of diabetes ranged from 1 to 25 years (mean 15.2±5.97) in group A. The patients were examined by an ocular response analyser (OCT-Optovue) that performs different GCC studies in addition to macular map analysis (EMM5). Best-corrected visual acuity in Snellen lines was also reported. Collected data were arranged and subjected to analysis using suitable statistical methods. Results In this study, a highly significant difference (P0.05) with the other studied GCC parameters. Compared with normative data, FLV% was abnormal in 70% of eyes, borderline in 6.67% of eyes and normal in 23.33% of eyes in diabetic macular oedema group compared with the control group, which showed values of 0, 6.67 and 93.33% for abnormal, borderline and normal values respectively, with χ2-test showing a highly significant difference (χ2=30.718 P<0.001) between both the groups. Conclusion Compared with normal group, patients with long-standing diabetic macular oedema showed higher mean values for all GCC parameters, which were strongly correlated with the central macular thickness. The FLV% values in particular was abnormal in ∼70% of eyes with diabetic macular oedema in comparison with normative data, and it correlated strongly with the duration of diabetes, so we recommend considering this parameter (FLV%) for seriously treating diabetic macular oedema before permanent GCC damage occurs.

Keywords

• diabetic macular oedema
• focal loss volume
• ganglion cell complex parameters
• ocular coherence tomography