2型糖尿病人群早期中心视力损伤的流行病学队列研究

The well-accepted strategy for prevention and treatment of diabetic eye complications focused on confirmed diabetic retinopathy, diabetic macular edema, cataract, etc, and there was no definitive therapy for preclinical central visual acuity (CVA) impairment, mainly because of its unknown pathogenesis. In our previous population-based study, the prevalence rate of early CVA impairment was as high as 9.1%, and that obviously limits the effects of diabetic eye diseases prevention and early-stage treatment strategy. Of note, the choriocapillaris is the only route for metabolic exchange in the retina within the foveal avascular zone, it was speculated that early CVA impairment is related to diabetic choroidopathy (DC). Recent research shows that the decreased macular choriocapillaris vessel density (MCVD) in diabetic eye ,which indicating early ischemia, is already present before diabetic macular edema can be observed; we have observed subfoveal choroidal thickness (SFCT) decreased significantly in the early CVA impairment patients. However, up til now, there was no epidemiology report on early CVA impairment in Chinese diabetes population. The present grant application is in line with the guideline of National Science Foundation of China (NSFC) which now supports cohort epidemiology study on eye diseases. In the present study, we plan to conduct a 3-year perspective cohort observation of 2217 Chinese type 2 diabetic residents without diabetic retinopathy, diabetic macular edema, cataract and other vision impairing diseases, trying to find out related physical and biochemical risk factors. The results will facilitate discriminating high risk groups of early CVA impairment in diabetic patients. In the same time, a quantitative relationship between SFCT change, MCVD change and CVA change will be established. This study will demonstrate the role of DC in the occurrence of preclinical CVA impairment, and provide important theoretic evidence of blocking agents which target on DC.

我们前期研究发现在排除黄斑水肿和白内障等眼病后，不明原因的早期中心视力(CVA)损伤在2型糖尿病人群中的患病率高达9.1%。由于这种损伤机制不明，尚无法干预，已严重影响到社区糖尿病人群眼病防治的依从性。根据黄斑区特殊解剖结构，我们推测这种损伤与糖尿病脉络膜病变(DC)相关。近期研究认为在未发生黄斑水肿的糖尿病眼，黄斑区脉络膜毛细血管网血管密度(MCVD)下降提示局部早期缺血；我们前期观察到在早期CVA损伤的糖尿病眼，黄斑中心凹下脉络膜厚度(SFCT)明显下降。但这些脉络膜病变是否导致早期CVA损伤，仍需进一步研究确认。鉴于国家自然科学基金现支持眼科流行病学队列研究，本项目拟对2217名已建档的2型糖尿病居民进行3年前瞻性队列研究，筛选出与早期CVA损伤相关的个体特征、生化等预测指标，明确其与SFCT及MCVD改变的关系，进而为探讨早期CVA损伤的发生机制，针对DC开展早期干预提供科学依据。

我们前期研究发现在排除黄斑水肿和白内障等眼病后，不明原因的轻度视力损伤 (UMVI)在2型糖尿病人群中的患病率高达9.1%。由于这种损伤机制不明，尚无法干预，已严重影响到社区糖尿病人群眼病防治的依从性。根据黄斑区特殊解剖结构，我们推测这种损伤与糖尿病脉络膜病变(DC)相关。本研究对上海市新泾地区2型糖尿病患者展开了为期3年的前瞻性队列研究，收集收集受试者一般资料、予以血压测量，糖化血红蛋白（HbA1C）、甘油三酯、总胆固醇和血肌酐检验，视力、裂隙灯、直接检眼镜和眼底照相检查及OCT检查。结果发现，UMVI人和眼-2年发生率分别为4.06%和2.59%。血红蛋白A1c水平升高，中心凹区、旁中心凹下方及颞侧脉络膜厚度变化较明显的患者更易出现UMVI。我们建议将黄斑区脉络膜厚度的变化作为监测VMI进展的指标。进一步OCTA发现与视力正常的糖尿病眼相比，UMVI眼血管面积密度（VAD）明显降低，中央凹无血管区域（FAZ）明显增大，在深层视网膜层（DRL）中差异显著。同时，确认和UMVI罹患相关的过氧化物酶体增生物激活受体γ(PPARG)基因型 (rs10865710和rs3856806)。进而为探讨UMVI的发生机制，开展早期干预提供科学依据。