Correlation between metamorphopsia and disorganization of the retinal inner layers in eyes with diabetic macular edema

Abstract

Purpose: To investigate factors associated with the severity of metamorphopsia secondary to diabetic macular edema (ME) by evaluating optical coherence tomography (OCT) parameters including disorganization of the retinal inner layers (DRIL). Methods: We retrospectively reviewed medical records of 37 eyes of 37 consecutive patients with diabetic ME or resolved diabetic ME, who underwent spectral-domain OCT examination and metamorphopsia assessment with M-CHARTS on the same day between November 2017 and March 2018. Age, sex, visual acuity, lens status, treatment history, and factors analyzed on OCT examination including DRIL length were evaluated in association with M-CHARTS scores. Results: Metamorphopsia was detected in 20 eyes (54%). The patients with metamorphopsia were relatively older than those without it (P = 0.060), and DRIL length was relatively longer in eyes with metamorphopsia (P = 0.065), while visual acuity was significantly better in eyes without metamorphopsia (P = 0.048). In correlation analyses to the severity of metamorphopsia, the DRIL length was the only OCT parameter associated with the M-CHARTS score (P = 0.035), while age, visual acuity, and ME were not significantly associated with the severity of metamorphopsia (P = 0.051, 0.060, and 0.344, respectively). Conclusion: The DRIL length was significantly associated with the severity of metamorphopsia secondary to diabetic ME. The inner retinal layer plays a key role in the development of metamorphopsia in eyes with diabetic ME. Metamorphopsia should be carefully considered when treating diabetic ME since its severity has been found to be independent of visual acuity and ME status.