Purpose

To investigate conjunctival vascular density (VD) using Anterior Segment Optical Coherence Tomography Angiography (OCTA) in Scleral Contact Lens (ScCL) wearers.

Methods

In this cross-sectional study, the conjunctival blood VD was assessed using OCTA with an anterior segment lens adapter. The nasal surface of each eye (6 ×6 mm) was scanned to a depth of 800 μm with ScCL and fifteen minutes after removing the lens. Conjunctival VD was defined as the percentage of the scanned volume occupied by vessels in which blood flow was measured. Measures of limbal indentation were subjectively determined by two independent observers using Anterior Segment Optical Coherence Tomography (AS-OCT). Comparisons between VD measurements before and after ScCL removal and correlations between conjunctival VD, time of use, vault and indentation values were also investigated.

Results

A total of 23 patients (3 females, 20 males) with keratoconus, with a mean age (years±SD) of 38.74±10.38 were included in the study. VD was significantly higher without ScCL (71.75%±2.97) than VD measured with ScCL (69.81%±2.63), p=0.02. A moderately negative correlation was found between indentation and vault (r=-0.44, p<0.05) and a positive tendency regarding the time of wearing ScCL and indentation (r=0.11 and r=0.068, respectively).

Conclusions

Using OCTA with an anterior segment lens adapter, the ocular surface blood VD was imaged and assessed with good repeatability and reliability. This study presents a new possible application of OCTA to investigate and monitor conjunctival vasculature in ScCL wearers. This results cautiously suggest that the repeated use of ScCL can cause vascular alterations in conjunctiva of the eyes of ScCL wearers, possibly due to a hidden hypoxia caused by prolonged limbal indentation.

中文翻译：

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使用光学相干断层扫描血管造影分析巩膜接触镜佩戴者的结膜血管密度

目的

使用眼前节光学相干断层扫描血管造影术 (OCTA) 在巩膜隐形眼镜 (ScCL) 佩戴者中研究结膜血管密度 (VD)。

方法

在这项横断面研究中，使用 OCTA 和前段透镜适配器评估结膜血 VD。在移除晶状体后十五分钟，用 ScCL 将每只眼睛的鼻表面 (6 × 6 mm) 扫描到 800 μm 的深度。结膜 VD 定义为测量血流的血管在扫描体积中所占的百分比。角膜缘压痕的测量由两名独立观察者使用眼前节光学相干断层扫描 (AS-OCT) 主观确定。还研究了 ScCL 去除前后 VD 测量值之间的比较以及结膜 VD、使用时间、穹窿和压痕值之间的相关性。

结果

共纳入23例圆锥角膜患者（3例女性，20例男性），平均年龄（岁±SD）为38.74±10.38。没有 ScCL 的 VD (71.75%±2.97) 显着高于使用 ScCL 测量的 VD (69.81%±2.63)，p=0.02。发现压痕和拱顶之间存在中度负相关（r=-0.44，p<0.05），而佩戴 ScCL 和压痕的时间呈正趋势（分别为 r=0.11 和 r=0.068）。

结论

使用 OCTA 和眼前节镜头适配器，对眼表血液 VD 进行成像和评估，具有良好的可重复性和可靠性。本研究提出了一种可能的 OCTA 新应用来调查和监测 ScCL 佩戴者的结膜脉管系统。这一结果谨慎地表明，重复使用 ScCL 会导致 ScCL 佩戴者眼睛结膜的血管改变，这可能是由于长期角膜缘压痕引起的隐性缺氧。