Correlation of retinal sensitivity, visual acuity and central macular thickness in different types of diabetic macular edema

Abstract

To detect the correlation of retinal sensitivity, visual acuity and central macular thickness in patients with different types of diabetic macular edema (DME), macular function were evaluated by measuring the sensitivity, fixation pattern of the macular was examined by fundus-related microperimetry, then analyzed and compared the results with best-corrected visual acuity (BCVA) and foveal retinal thickness measured by optical coherence tomography (OCT). A retrospective case-series study. In a prospective, observational case series study, 52 consecutive patients (83 eyes) with diabetic macular edema were included.Sex, age,BMI, education, type of DM, duration, treatment, laboratory examinations, history of cardiovascular disease, hypertension, hyperlipidemia, diabetic nephropathy, and cigarette use were documented.Logarithm of the minimum angle of resolution (logMAR) BCVA was evaluated using the international vision test chart.Foveal thickness was measured by OCT. Mean retinal sensitivities, fixation stability and position was investigated with microperimetry. Variables related with BCVA, foveal thickness and mean retinal sensitivities were analyzed in different types of DME patients using one-way ANOVA or Kruskal-Wallis test. As for fixation, Fisher exact test was chosen. Pearson Correlation analysis was performed to evaluate the association between these variables. Spearman correlation analysis was used for ordinal data. The correlation between retinal sensitivities and all the variables examined were analyzed under multiple regression analysis. Eighty-three eyes were included in this study. Forty-seven eyes (56.63%) were graded as focal DME, 20 eyes (24.10%) as diffuse DME, 5 eyes (6.02%) as ischemic DME and 11 eyes (13.25%) as proliferative DME. Comparison between different types of DME patients showed statistically significant difference in mean logMAR BCVA (F = 12.737, P < 0.01) , mean OCT foveal thickness (H = 31.504, P < 0.01) , mean central retinal sensitivities (F = 14.760, P < 0.01) , and patterns of fixation, which were also statistically correlated (χ(2)= 23.47, 21.01; P < 0.01). It was a positive correlation between OCT foveal thickness and logMAR BCVA in patients with focal, diffuse and ischemic DME (r = 0.56, -0.62; P < 0.01) , but not with proliferative DME (r = 0.43, P = 0.19) .While central retinal sensitivities were also negative correlation between OCT foveal thickness and logMAR BCVA (r = -0.62, -0.68; P < 0.01) . Multiple regression analysis showed that central retinal sensitivity was inversely correlated with LogMAR and retinal thickness (t = -5.52, -4.24; P < 0.01). There are statistically significant difference in macular morphology and vision function between different types of DME patients. The progression of DME are expressed gradually from focal, diffuse to ischemic type. DME could be fully evaluated by measuring macular sensitivity, fixation pattern with microperimetry as well as macular thickness measurement with OCT and visual acuity determination comprehensively.