方法：回顾性对照研究。选取2015-01/2020-10于苏州大学附属第一医院就诊的早期圆锥角膜患者55例62眼，选取同期接受近视激光手术治疗的屈光不正患者110例110眼作为对照组。采用FD-OCT测量获得以瞳孔中心7mm直径范围的角膜上皮层厚度参数、以瞳孔中心9mm直径范围25个分区的角膜上皮层平均厚度值及角膜全层平均厚度值，比较各参数值在早期圆锥角膜组及对照组的差异，对有差异的参数分析诊断价值。

结果：早期圆锥角膜组Min_-e值较对照组显著减小，Std.Dev值、Max-Min_-e值、Max_-e值较对照组显著增大(均P<0.001)。Std.Dev值、Max-Min_-e值对早期圆锥角膜诊断效能较高(AUC=0.937、0.928)，Max_-e值、Min_-e值诊断效能中等(AUC=0.871、0.797)。25个分区角膜上皮厚度分析，早期圆锥角膜组内环颞下区(EIT₁)角膜上皮层厚度变薄最明显，诊断效能最高(AUC=0.827)。各区域角膜全层厚度分析，早期圆锥角膜组各个分区的角膜全层平均厚度值较对照组明显变薄，内环颞下区(CIT₁)平均厚度值在25个分区中具有较高的诊断效能(AUC=0.903)。

结论：角膜上皮层厚度参数Std.Dev值、Max-Min_-e值、Max_-e值、Min_-e值、内环颞下区角膜上皮层平均厚度值以及内环颞下区角膜平均厚度值可用于鉴别早期圆锥角膜。

METHODS: Retrospective control study. Patients with early keratoconus who were admitted to the Department of Ophthalmology of the First Affiliated Hospital of Soochow University from January 2015 to October 2020 and patients who received laser refractive surgery for myopia during the same period were included in this study. Using FD-OCT to measure the cornea in circle centralized by the pupil and with diameter of 9mm in the early-keratoconus group and the control group. This was to obtain the thickness parameter of corneal epithelium with diameter of 7mm, the respective averaged thickness value of corneal epithelium and the respective averaged thickness value of the full corneal layer on each of the 25 divisions. The parameter value differences between the early-keratoconus group and the control group were compared, and the diagnosis value of parameters that hold difference was analyzed.

RESULTS: The Min_-e value in early-keratoconus group was significantly lower than that of the control group. On contrary, the value of Std.Dev, Max-Min_-e, and Max_-e were significantly higher in early-keratoconus group than that in latter one(all P<0.001). The value of Std.Dev and Max-Min_-e hold a greater diagnostic efficiency on diagnosis of early keratoconus(AUC=0.937, 0.928), while Max _-e value and Min_-e value performed a medium diagnostic efficiency(AUC=0.871, 0.797). Analysis on thickness of corneal epithelium on the 25 divisions found that the thickness of corneal epithelium at infratemporal region of inner ring(EIT₁)became thinner most obviously in early-keratoconus group, with greatest diagnostic efficiency(AUC=0.827). The average corneal thickness of the 25 zones of the early keratoconus group was significantly thinner than that in the normal control group. Averaged corneal thickness at infratemporal region of inner ring(CIT₁)hold a relatively high diagnostic efficiency among the 25 divisions(AUC=0.903).

CONCLUSION: The parameter values of corneal epithelium thickness including Std.Dev, Max-Min_-e, Max_-e, Min_-e, the averaged thickness value of corneal epithelium at infratemporal region of inner ring, and the thickness value of full corneal layer at infratemporal region of inner ring can all be used for diagnosis of early keratoconus.