VST Glaucoma Center, L V Prasad Eye Institute, Dr. Kallam Anji Reddy campus, Banjara Hills, Hyderabad, India.
Brien Holden Vision Institute, Sydney, NSW, Australia.
Eye (Lond). 2020 Aug;34(8):1399-1405. doi: 10.1038/s41433-019-0666-x. Epub 2019 Nov 6.
To assess the ability of teleophthalmoscopic grading of peripheral anterior chamber depth (PACD) using the van Herick (vH) technique in detecting gonioscopically occludable angle; and to determine whether combining results from vH grading and ocular biometry can improve the accuracy to diagnose gonioscopically occludable angle METHODS: This cross-sectional study was an offshoot of a rural population-based study, Glaucoma Epidemiology and Molecular Genetic Study (GLEAMS). A masked urban ophthalmologist graded digital slit lamp photographs of PACD by vH technique. Sussman four-mirror lens was used to perform dark room indentation gonioscopy. Cutoff values of the tests were, vH technique: grade ≤ 2, central anterior chamber depth (ACD), as well as axial length: ≤ 25th percentile and lens thickness ≥ 75th percentile value of the study population.
We studied 1965 eyes of 1029 adult participants. The vH grade was ≤2 in 188 (9.5%) eyes. The angle was occludable by gonioscopy in 101 (5.1%) eyes. The performance of the vH test to rule out gonioscopically occludable angle was good [negative predictive value (NPV): 97.3%], despite low sensitivity (52.5%), while its efficacy to rule in the condition was low [positive predictive value (PPV): 28.2%] despite high specificity (92.8%). However, test combination strategy increased the PPV nearly twofold (53.8%). The calculated PPV at 10% prevalence of gonioscopically occludable angle was even higher (70.5%).
Van Herick technique can be incorporated into a teleophthalmology program by means of slit lamp photographs of PACD. Combined vH grading and ocular biometry improved the predictability of a gonioscopically occludable angle.
评估使用 van Herick（vH）技术通过 teleophthalmoscopy 分级周边前房深度（PACD）来检测房角镜下可阻塞角度的能力；并确定是否可以结合 vH 分级和眼部生物测量结果来提高诊断房角镜下可阻塞角度的准确性。
这项横断面研究是农村人群为基础的青光眼流行病学和分子遗传学研究（GLEAMS）的一个分支。一名经过培训的城市眼科医生使用 vH 技术对数字裂隙灯照片进行 PACD 的分级。使用 Sussman 四镜透镜在暗室中进行压陷房角镜检查。测试的截断值为：vH 技术：等级≤2，中央前房深度（ACD），以及轴向长度：≤研究人群第 25 百分位数和晶状体厚度≥第 75 百分位数值。
我们研究了 1029 名成人参与者的 1965 只眼。188 只眼（9.5%）的 vH 等级≤2。101 只眼（5.1%）的角度可通过房角镜检查阻塞。尽管敏感性低（52.5%），但 vH 测试排除房角镜下可阻塞角度的性能良好[阴性预测值（NPV）：97.3%]，而其排除该疾病的效能较低[阳性预测值（PPV）：28.2%]，尽管特异性高（92.8%）。但是，测试组合策略使 PPV 增加了近两倍（53.8%）。在房角镜下可阻塞角度的患病率为 10%的情况下，计算出的 PPV 甚至更高（70.5%）。
van Herick 技术可以通过 PACD 的裂隙灯照片纳入 teleophthalmology 计划。结合 vH 分级和眼部生物测量可提高房角镜下可阻塞角度的预测能力。
