Ischemic maculopathy at the preproliferative stage of diabetic retinopathy: epidemiology, clinical picture and diagnosis

BACKGROUND: One of the leading causes of central vision loss in patients with diabetic retinopathy is ischemic maculopathy, the incidence of which in diabetic retinopathy varies depending on the stage of the disease from 20 to 77% according to fluorescein angiography results. More accurate diagnosis of ischemic maculopathy is possible using the technique of optical coherence tomography angiography (OCTA). AIM: To study the prevalence and severity of ischemic maculopathy in patients with diabetes mellitus type 1 and 2 with preproliferative stage of diabetic retinopathy using OCTA. MATERIALS AND METHODS: 43 patients (72 eyes) of diabetic retinopathy levels 47 and 53, according to ETDRS criterions, were included in the study. The exclusion criterion was the presence of diabetic macular edema with involvement of the center of the macula. Patients were divided into 3 groups according to the ETDRS classification of ischemic maculopathy grade. Each of them was subject to standard ophthalmologic examination, OCT with determination with determination of central retinal thickness in macula zone and OCTA to evaluate the status of the foveolar avascular zone. RESULTS: Ischemic maculopathy level 1 was detected in 23 patients — group 1 (33 eyes), level 2 was detected in 23 patients (27 eyes) — group 2, and level 3 — in 8 patients (12 eyes) — group 3. A statistically significant difference using “IBM SPSS Statistics” version 27 was found between the foveolar avascular zone area scores of groups 1 and 2 — 0.18 mm2 versus 0.32 mm2 (p 0.001) and between groups 1 and 3 — 0.18 mm2 versus 0.98 mm2 (p 0.001), and between groups 2 and 3 — 0.32 mm2 versus 0.98 mm2 (p 0.008). In group 3, negative correlations were found between best-corrected visual acuity and foveolar avascular zone circumference length (r = –0.906, p = 0.02), foveolar avascular zone (r = –0.748, p = 0.033) and circularity index (r = –0.569, p = 0.141), while no such statistically significant difference was found in the other groups. CONCLUSIONS: In patients with diabetic retinopathy levels 47 and 53, ischemic maculopathy is revealed in 100% of cases. In 83.4% of cases, level 2 of the ischemic maculopathy is detected, and in 16.6% — level 3. Ischemic maculopathy of levels 1 and 2 has no significant effect on best-corrected visual acuity. Level 3 is clinically significant, as the change of parameters characterizing foveolar avascular zone, and first of all the increase of foveolar avascular zone circumference length above 500 µm, is associated with a decrease in best-corrected visual acuity.