Abstract
Purpose: :
OCT studies have suggested that the retinal nasal inner zones are thicker than the temporal zones. The purpose of this study was to evaluate the mfERG response in the nasal and temporal zone in diabetic (n=36) and non-diabetic eyes (n=18).
Methods: :
In 26 eyes (19subjects) without and ten eyes (8 subjects) with diabetic macular edema (DME); (age 56±14 and 62± 15, NS and duration 12±9 resp. 14±9 years , NS), retinal thickness was assessed with OCT in the nasal and temporal inner and outer zones. MfERG response from corresponding areas was analyzed in the diabetic patients and in 18 healthy controls. Calculations were made within and between the groups.
Results: :
Diabetic eyes had lower mfERG amplitudes in both the nasal and temporal areas (14±6 vs. 25±11 nV/deg2; p=0.000 and 17±7 vs. 26±11 nV/deg2; p=0.004) and longer implicit times (31±3 vs.26±2ms; p=0.000 and 30±3vs. 26±2ms; p=0.000) compared to healthy controls. Both diabetic eyes without and with DME showed lower mfERG amplitudes in the nasal compared to the temporal areas, 16±6 vs. 19±7 nV/deg2;p=0.001, and 11±5 vs. 14±5 nV/deg2; p=0.01, respectively. Implicit time did not differ between nasal and temporal area. In non diabetic eyes both amplitudes and latencies were equal in nasal and temporal areas. Eyes with DME had increased OCT thickness and lower mfERG amplitudes in the nasal zone compared to diabetic eyes without, 338±110 vs. 278 ±34µ; p= 0.018 and 11±5 vs. 16±6 nV/deg2; p=0.034.
Keywords: diabetic retinopathy • electroretinography: clinical • imaging/image analysis: clinical