Correlation analysis of visual sensitivity, best corrected visual acuity and central retinal thickness in diabetic macular edema

Abstract

Objective To investigate the correlation of visual sensitivity, best corrected visual acuity (BCVA) and central retinal thickness (CRT) in diabetic macular edema (DME). Methods A retrospectives study. Forty-five eyes of 30 patients in DME were included. There were 20 eyes of 16 males, 25 eyes of 14 females, with an average age of 54.49±7.45 years. All the patients had type 2 diabetes; the average duration of diabetes was over 10 years. The BCVA examination was performed using the international standard visual acuity chart, which was converted into logarithmic logarithm (logMAR) visual acuity. The following parameters provided by the MAIA microperimetric device were evaluated, including average threshold (AT), macular integrity index (MI), fixation indexes (P1 and P2), bivariate contour ellipse area (BCEA) for 63% and 95% of points, and horizontal and vertical axes of the ellipse of fixation (H63, H95, V63, V95). The CRT was measured and the integrity of the ellipsoidal band was observed by optical coherence tomography (OCT). The integrity of the ellipsoid band was divided into continuous smooth (group A): fully visible; part of the light band was interrupted (B group): not completely visible; missing light band (C group): completely invisible. Pearson correlation analysis was used to analyze the correlation between the factors; non-parametric tests were used to compare the logMAR BCVA, AT, and CRT between the different ellipsoid zone integrity groups; multiple linear regression analysis was used to analyze factors related to AT. Results Pearson correlation analysis showed that the logMAR BCVA was positively correlated with MI (r=0.303, P=0.04) and CRT (r=0.342, P=0.02), negatively correlated with AT (r=−0.59, P=0.00) and P1 (r=−0.38, P=0.01). There was negative correlation between AT and MI (r=−0.55, P=0.00). The result of multivariate linear regression analysis showed that the logMAR BCVA is inversely correlated with AT (t=−3.53, P=0.001). Group A, B and C were 23, 17 and 5 eyes in the 45 eyes, respectively. There were significant differences in logMAR BCVA, AT, and CRT between the three groups of eyes (P=0.045, 0.049, 0.018). Conclusions In DME patients, the logMAR BCVA was positively correlated with CRT, negatively correlated with AT and P1. The logMAR BCVA is inversely correlated with AT. Microperimetry combined with OCT and visual acuity can be used to assess the visual function of patients with DME. Key words: Diabetic retinopathy/complications; Macular edema; Visual fields; Tomography, optical coherence