Classification of diabetic macular edema according to optical coherens tomography and fundus fluorescene angiography findings and evaluation of response to treatment retrospectively

Purpose: To evaluate the response to intravitreal treatment by classifying Diabetic Macular Edema (DME) according to optical coherence tomography (OCT) and fundus fluorescein angiography (FFA) findings. Materials and Methods: The study was conducted by including 104 eyes of 78 patients diagnosed with DME and followed up with the diagnosis of diabetic retinopathy between January 2013 and August 2021. File records of the patients were reviewed retrospectively. Visual acuity and central retinal thickness were recorded before and after treatment. DME was divided into 3 groups according to OCT findings as diffuse macular edema, cystoid macular edema, and cystoid degeneration. In addition, each group was divided into subgroups according to the presence of serous macular detachment (SMD), hard exudate, ellipsoid zone disruption and vitreomacular interface disorder. The patients were divided into 4 groups according to their FFA findings as no ischemia, macular and posterior equator ischemia only, peripheral ischemia only, and whole retina ischemia. Results: Of the 104 eyes included in the study, 52 were right and 52 were left eyes. 46 (59%) patients were male and 32 (41%) were female, with a mean age of 60.4± 10.09 (36-82). All patients had type 2 diabetes and the mean duration of diabetes was 15.93±7.22 (2-34) years. Of 104 eyes, 56 (53.8%) had NPDR and 48 (46.2%) had PDR. The mean follow-up period of the patients was 3.35±2.88 (1-15) years. The patients received an average of 6.25±3.04 (3-12) anti-VEGF injections during the follow-up period. In the study, DME subtypes were found to be 71.1% for CME, 23.1% for diffuse DME, and 5.8% for KD. Ellipsoid zone disruption was found in 15.4%, SMD 26.8%, DRIL 61.5%, hard exudate 55.8%, interface disorder 17.2% in patients with DME. Visual acuity before treatment was 0.53±0.45 (0.00-2.10) logMAR and after treatment 0.56±0.473 (0,00-2,10) logMAR. There was no statistically significant difference in visual acuity change before and after treatment. (p=0.437) The best visual acuity was 0.50 logMAR in the CME group and the worst was 0.60 logMAR in the diffuse edema group. When visual acuity was evaluated according to OCT findings, visual acuity increased after treatment only in SMD patients, but it was not found to be statistically significant. (p=0.396) In the logistic regression analysis performed to evaluate the relationship between vision change and OCT findings, SMD was found to be the parameter that least affected visual acuity. (OR: 0.672). The lowest visual acuity before and after treatment was seen in those with ellipsoid zone disorder, and the highest visual acuity was seen in those with hard exudate. When the central retinal thickness was evaluated, it was 402.20±167.01 (139-852) µm before the treatment and 348.24±152.64 (78-811) µm after the treatment, and the change was statistically significant. (p=0.002) When the visual acuity was evaluated according to the FFA groups, the highest visual acuity was seen in the group without ischemia, both before and after the treatment, and the lowest visual acuity was observed in the group with ischemia in the entire retina. Except for the group with ischemia in the entire retina, visual acuity decreased in the other groups. (p=0.176) Conclusion: The group with the lowest visual acuity is the diffuse DME group. It was observed that SMD responded better to treatment compared to other OCT findings. Only in the group with entire retinal ischemia, visual acuity improved after treatment. Key Words: Diabetic macular edema, OCT, biomarker, serous macular detachment