Department of Ophthalmology, Mbarara University of Science and Technology.
Department of Ophthalmology, Military 34 Hospital, Republic of Sierra Leone Armed Forces, Freetown, Western Area, Sierra Leone.
J Glaucoma. 2021 Mar 1;30(3):e90-e98. doi: 10.1097/IJG.0000000000001779.
Using optical coherence tomography (OCT) measurements as a reference standard for vertical cup-to-disc ratio (vCDR), a smartphone-based ophthalmic camera has a sensitivity of 67.7% and specificity of 96.7% to detect a vCDR>0.5.
The purpose of this study was to assess the performance of a smartphone-based ophthalmic camera system using an Apple iPhone 6S and an adapter, Paxos Scope, to obtain adequate dilated fundus photos to measure clinically useful vCDR cutoffs.
Adult patients from a government tertiary level eye hospital in Southwestern Uganda were prospectively recruited from January to April 2019. All patients experienced a comprehensive eye examination, dilated posterior segment indirect ophthalmoscope imaging with the Paxos Scope, and spectral-domain OCT imaging with a Cirrus HD-OCT to measure vCDR. Patients' eyes excluded had media opacities or existing disease precluding a view of the fundus. Fundus images underwent a single masked review to assign vCDR at increments of 0.1. Descriptive statistics, parametric and χ2 tests for significance, repeated measures correlation, κ, receiver operating characteristics curve, and Bland-Altman were used to assess the data.
Among 467 (consecutive) individuals, fundus photographs acquired with the Paxos Scope demonstrated a 67.7% [95% confidence interval (CI), 63.0-72.0] sensitivity and 96.7% (95% CI, 94.2-98.3) specificity to detect a vCDR>0.5, using OCT as the reference standard. A total of 138 eyes were excluded due to poor imaging acquisition, such as dense cataract, rendering 796 eyes for analysis. The vCDR from graded Paxos Scope images and OCT correlated well with repeated measures correlation of 0.82 (95% CI, 0.77-0.86, P<0.001) and agreement, dichotomized as >0.5 or ≤0.5, was 80.9% (κ=0.63±0.034, P<0.001). Among glaucoma and glaucoma suspects (85 eyes), the sensitivity and specificity dichotomized using vCDR>0.5 were 97.5% (95% CI, 91.3-99.7) and 80.0% (95% CI, 28.4-99.5), respectively. The area under the receiver operating characteristics curve was 0.92 (95% CI, 0.89-0.94) for all eyes and 0.98 (95% CI, 0.78-1.0) for glaucoma and glaucoma suspects.
The Paxos Scope produced images that can be reliably used to estimate vCDR, which is closely aligned with the automated algorithm from the OCT optic disc cube scan. The low-cost, ready-to-integrate adapter, and minimal training requirements make it a viable option for population-based screening in low-resource settings.
使用光学相干断层扫描（OCT）测量作为垂直杯盘比（vCDR）的参考标准，基于智能手机的眼科相机检测 vCDR>0.5 的灵敏度为 67.7%，特异性为 96.7%。
本研究旨在评估基于智能手机的眼科相机系统的性能，该系统使用 Apple iPhone 6S 和适配器 Paxos Scope 获取足够的散瞳眼底照片，以测量临床有用的 vCDR 截止值。
2019 年 1 月至 4 月，来自乌干达西南部一家政府三级水平眼科医院的成年患者前瞻性入组。所有患者均接受全面的眼部检查，使用 Paxos Scope 进行散瞳后节间接检眼镜成像，使用 Cirrus HD-OCT 进行光谱域 OCT 成像以测量 vCDR。排除存在影响眼底观察的眼部混浊或疾病的患者。眼底图像由一位经验丰富的观察者进行单一盲法评估，以 vCDR 为 0.1 的增量进行分配。采用描述性统计、参数和 χ2 检验、重复测量相关性、κ、受试者工作特征曲线和 Bland-Altman 分析数据。
在 467 名（连续）患者中，使用 Paxos Scope 获取的眼底照片检测 vCDR>0.5 的灵敏度为 67.7%（95%置信区间，63.0-72.0），特异性为 96.7%（95%置信区间，94.2-98.3），以 OCT 为参考标准。由于成像采集不佳（如密集性白内障），共排除了 138 只眼，因此可用于分析的眼数为 796 只。分级 Paxos Scope 图像和 OCT 的 vCDR 相关性良好，重复测量相关性为 0.82（95%置信区间，0.77-0.86，P<0.001），一致性为 80.9%（κ=0.63±0.034，P<0.001），分为>0.5 或≤0.5。在青光眼和疑似青光眼患者（85 只眼）中，vCDR>0.5 的灵敏度和特异性分别为 97.5%（95%置信区间，91.3-99.7）和 80.0%（95%置信区间，28.4-99.5）。所有患者的受试者工作特征曲线下面积为 0.92（95%置信区间，0.89-0.94），青光眼和疑似青光眼患者的曲线下面积为 0.98（95%置信区间，0.78-1.0）。
Paxos Scope 生成的图像可可靠地用于估计 vCDR，与 OCT 视盘立方扫描的自动算法密切一致。这种低成本、易于集成的适配器和较少的培训要求使其成为资源匮乏环境中人群筛查的可行选择。
