Observation of macular microvascular changes in eyes of patients of type 2 diabetes without clinical ;features of diabetic retinopathy by optical coherence tomography angiography / 中华眼底病杂志

ABSTRACT

Objective To observe the morphological changes of macular capillary in type 2 diabetic mellitus (DM) patients without clinical features of diabetic retinopathy (DR) by optical coherence tomography angiography (OCTA). Methods This is a prospective clinical case-control study. Forty-three eyes of 22 patients with DM without clinical features of DR (case group) and 40 control eyes of 20 age-and sex-matched healthy physical examination subjects (control group) were enrolled in this study. All subjects underwent OCTA examination with mode of retinal blood flow imaging, macular 3 mm×3 mm and 6 mm×6 mm area, signal strength>45. Foveal avascular zone (FAZ) area, foveal capillary density, parafovea capillary non-perfusion, and micro-aneurysm in shallow capillary vessel layer were evaluated. Results In case group, the mean FAZ area was (0.397±0.141) mm2 and the mean foveal capillary density was (44.6±0.62)%. In control group, the mean FAZ area was (0.253±0.112) mm2 and the mean foveal capillary density was (48.6±0.58)%. FAZ area of eyes in case group was larger than that in control group (t=1.017, P0.05). The spider web-like FAZ and normal foveolar avascular zone were observed in eyes of control group. The parafovea capillary non-perfusion, abnormal foveolar avascular zone, micro-aneurysm and tortuosity of vessels were observed in eyes of case group. Parafovea capillary non-perfusion (χ2=4.542), micro-aneurysms (χ2=5.183) were seen more often in case group than control group (P<0.05). Conclusion Type 2 DM patients have abnormal retinal vascular microcirculation before DR using OCTA, including larger FAZ area, parafovea capillary non-perfusion, abnormal foveolar avascular zone, micro-aneurysm and tortuosity of vessels.