INFLUENCE OF HIGH MYOPIA ON CHORIOCAPILLARIS PERFUSION AND CHOROIDAL THICKNESS IN DIABETIC PATIENTS WITHOUT DIABETIC RETINOPATHY

To investigate the impact of high myopia on choriocapillaris perfusion and choroidal thickness (CT) in diabetic patients without diabetic retinopathy.Healthy subjects and patients with diabetes mellitus were recruited from communities in Guangzhou. They were divided into four groups according to the presence of diabetes and high myopia: healthy control (n = 77), diabetes (n = 77), high myopia (n = 77), and diabetes with high myopia (n = 77). Swept-source optical coherence tomography angiography (SS-OCTA) measured choriocapillaris perfusion and CT. Choriocapillaris perfusion was quantified using the choriocapillaris perfusion index (CPI).A total of 308 subjects (308 eyes) were included in the study. The average CPI was 91.11 ± 0.84, 90.16 ± 1.46, 89.80 ± 1.42, and 89.36 ± 1.19% in the control, diabetes, high myopia, and diabetes with high myopia groups, respectively (P < 0.001); the average CT was 227.55 ± 43.13, 205.70 ± 59.66, 158.38 ± 45.24, and 144.22 ± 45.12 µm, respectively (P < 0.001). After adjusting for age and sex, the average CPI decreased 0.95 ± 0.20% (P < 0.001) in the diabetes group, 1.33 ± 0.20% (P < 0.001) in the high myopia group, and 1.76 ± 0.20% (P < 0.001) in the diabetes with high myopia group relative to the control group; the average CT decreased 23.53 ± 8.12 (P = 0.004), 70.73 ± 9.41 (P < 0.001), and 85.90 ± 8.12 µm (P < 0.001), respectively. Further adjustment for other risk factors yielded a similar result.Diabetes and high myopia significantly affect CPI and CT, and the presence of both conditions is more damaging to CPI and CT than diabetes or high myopia alone.