Background: Diabetic retinopathy (DR) is a common complication of diabetes mellitus and is a leading cause of blindness worldwide. Diabetic macular ischemia is recognized as an important cause of visual disability. DMI is characterized by enlargement of the physiological capillary-free zone (FAZ).
Objective: To compare fluorescein angiography (FA) and optical coherence tomography angiography (OCTA) of foveal avascular zone (FAZ) in patients with diabetic retinopathy (DR) with and without diabetic macular ischemia (DMI).
Patients and methods: Our study included 60 patients with diabetic retinopathy, divided into 2 groups: Group I: 80 eyes of diabetic patients with diabetic retinopathy and DMI and Group II: 40 eyes of diabetic patients with. Diabetic retinopathy and no DMI (diagnosed clinically and FA). All of them underwent full history taking, complete ophthalmological examination including FFA & OCTA during the period from October 2017 to December 2018.
Results: Regarding the comparison of OCTA with FA in diagnosis of DMI according to ETDRS DMI grading. The present study found that moderate agreement between both devices (Kappa agreement k = 0.560 FAZ area was measured in DMI group and non DMI group. Group I Mean FAZ area ± SD was (0.57 ± 0.29 mm2) in OCTA6x6, (0.61 ± 0.28mm2) in FFA. Statistically, the difference in FAZ area between the OCTA and FFA was insignificant. The horizontal and vertical diameter was (650 ± 0.32Mm & 490 ±0.26) in OCTA6x6, (690 ± 0.25Mm & 530 ± 0.31Mm) in FFA. Statistically, the difference in horizontal and vertical diameter between the OCTA and FFA was insignificant.
Conclusion: OCT angiography was a valid, reliable and easy-to-use method to detect and quantify DMI changes without use of dye .with a moderate degree of agreement between FFA and OCTA in evaluating DMI.