Yao Yao, Yanni Yan, Wenbin Wei,* Qian Wang* 

Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Wenbin Wei; Qian Wang, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, People’s Republic of China, Email weiwenbintr@163.com; xiaoqian912@foxmail.com

Purpose: Understanding the dynamics of blood flow regulation in diabetic conditions is crucial for developing targeted interventions. This study aimed to investigate the impact of acute intraocular pressure (IOP) elevation on retinal and choroidal microvasculature in diabetic and control rats.
Methods: Male Sprague-Dawley rats were divided into two groups: diabetic and control. Acute IOP elevation was achieved through controlled perfusion pressure. Retinal and choroidal blood flow was measured using Swept-Source Optical Coherence Tomography Angiography (SS-OCT/OCTA).
Results: At baseline IOP levels, there were no statistically significant differences in perfusion area (PA) between the two groups in all regions of the retina and choroid. During acute IOP elevation, both diabetic and control rats experienced a significant reduction in retinal and choroidal blood flow perfusion. Diabetic rats manifested significantly higher (P< 0.05) alterations in PA across nearly all retinal regions compared to the control group, barring specific sub-regions of the outer ring. Concerning choroidal PA, the diabetic group exhibited a more pronounced alteration than the control group across the entire 6-mm region and certain sub-regions of the outer ring.
Conclusion: Our results demonstrate a clear association between diabetes and impaired choroidal vascular autoregulation during acute IOP elevation. The observed reduction in retinal and choroidal microvasculature in diabetic rats points towards a compromised ability to maintain blood flow homeostasis under stress conditions.

Keywords: diabetes, retinal blood flow, choroidal perfusion, optical coherence tomography angiography, intraocular pressure, vascular autoregulation