Correlation of visual acuity and central macular thickness in diabetic macular edema

Abstract

PurposeTo investigate the correlation of retinal thickness measured with SD OCT and visual acuity in eyes with diabetic macular edema (DME) before and after intravitreal injection of anti‐VEGFMethodsSeventy‐four patients (96 eyes) with DME who underwent three monthly intravitreal injection of bevacizumab (IVB) as their first treatment. Type of DM, duration, treatment, laboratory examinations, history of cardiovascular disease, hypertension, hyperlipidemia, diabetic nephropathy, were documented. Logarithm of the minimum angle of resolution (logMAR) best corrected visual acuity (BCVA) was evaluated using the international vision test chart. Foveal thickness was measured by SD OCT.ResultsThe correlation coefficients for visual acuity (VA) versus OCT center point thickness were 0.57 at baseline and 0.47, 0.38, and 0.40 at 1, 3, and 6 months post‐laser photocoagulation. A subset of eyes showed paradoxical improvements in VA with increased center point thickening (5–13% at the three time points) or paradoxical worsening of VA with a decrease in center point thickening (12–24% at the three time points).ConclusionsThere is modest correlation between OCT‐measured center point thickness and VA, and modest correlation of changes in retinal thickening and visual acuity following focal laser treatment for DME. In addition, paradoxical changes in VA and retinal thickening may be observed. Indeed, retinal thickness only accounts for up to 27% of variability in concurrently measured VA suggesting that other factors are important determinants of VA in the presence of diabetic macular edema.