Macular Function by Multifocal Electroretinogram in Diabetic Macular Edema after Intravitreal Triamcinolone Acetonide Injection

Abstract

The purpose of this study was to assess macular function by multifocal electroretinography (mfERG) in eyes with diabetic macular edema (DME) after intravitreal triamcinolone acetonide (IVTA) injection. Fifteen eyes of 15 patients with DME scheduled for 4 mg IVTA injection were prospectively recruited. The response to treatment was monitored functionally by visual acuity (VA) measurement and mfERG and anatomically by foveal thickness measured by optical coherence tomography (OCT). The first-order kernel P1 mfERG responses from 0 to 7 degrees (central) and 7 to 25 degrees (peripheral) were grouped and analyzed. Changes in functional parameters (VAs and the P1 mfERG response amplitudes and peak latencies) and morphometric parameters (OCT foveal thickness) in eyes with DME 1 and 3 months after IVTA injection were compared with baseline values by Student t test. The mean baseline logMAR value for VAs of the patients before treatment was 0.49+/-0.26. After treatment, it was 0.27+/-0.23 at 1 month and 0.26+/-0.18 at 3 months, and differences from pretreatment values were significant (for each, p<0.001). There were statistically significant decreases in the mean foveal thickness at 1 and 3 months after treatment compared with pretreatment values (for each, p<0.001). There were also statistically significant increases in the mean P1 response amplitude for both central and peripheral groups at all examinations compared with pretreatment (for each, p<0.001). The mean P1 peak latencies for both the central and peripheral groups were shortened, but not significantly. As well as the reduction in DME and improvement in VA, IVTA injection improves macular function as assessed by mfERG in diabetic patients.