Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, USA.
Shiley Center for Research and Education, Scripps Institute, La Jolla, CA, USA.
Clin Hemorheol Microcirc. 2019;72(2):119-128. doi: 10.3233/CH-189908.
Orthokeratology (Ortho-K) is an over-night hard contact lens therapy, which physically reshapes the corneal curvature in order to stabilize or temporally eliminate myopia in patients. We hypothesize that the prolonged physical contact and mechanical pressure induced by the Ortho-K lenses may create lasting inadvertent effects and damages (microangiopathy), and may bring about unwanted changes in the microvasculature of the bulbar conjunctiva. Computer-assisted intravital microscopy (CAIM) was used to view, document (via videotaping) and objectively quantify (via computer-assisted image analysis) the real-time dynamic and morphometric characteristics of the conjunctival microcirculation in long-term (at least over one year) Ortho-K patients (n = 11) and matched non-user control subjects (n = 8). Ortho-K patients were instructed to wear their lenses overnight following standard protocol. During the study, the conjunctival microcirculation of the left eye of all Ortho-K lens users was viewed, frequently re-focused and videotaped, without and with the lens in place, as outlined in Methods. The matched control subjects (non-lens wearing) were videotaped and studied in like manner. The dynamic and morphometric characteristics of each user and control subject were analyzed, quantified and summated as a severity index (SI) collectively for comparison. SI of Ortho-K lens users (4.18±1.08) differed significantly from SI of control subjects (1.75±1.39, p≤0.05). In addition, changes in the conjunctival microcirculation (e.g., flow velocity, vessel diameter, shape change, etc) were viewed and videotaped immediately after the myopic patients put on the Ortho-K lenses. Eight of the 11 Ortho-K lens users displayed significant percentage changes (p≤0.05) in flow velocity and 10 of 11 displayed significant percentage changes (p≤0.05) in vessel diameter, without and with the Ortho-K lenses. The results clearly indicated that significant microvascular changes via tissue remodeling occurred, and were caused directly by the physical presence of the Ortho-K lenses.
角膜塑形术（Ortho-K）是一种过夜硬性角膜接触镜治疗方法，通过物理重塑角膜曲率来稳定或暂时消除患者的近视。我们假设 Ortho-K 镜片长时间的物理接触和机械压力可能会造成持久的、不经意的影响和损伤（微血管病变），并可能导致球结膜微脉管系统发生不需要的变化。我们使用计算机辅助活体显微镜（CAIM）来观察、记录（通过录像）和客观量化（通过计算机辅助图像分析）长期（至少一年以上）佩戴 Ortho-K 镜片的患者（n=11）和匹配的非使用者对照组（n=8）的结膜微循环的实时动态和形态特征。根据标准方案，我们指导 Ortho-K 患者在夜间佩戴镜片。在研究过程中，我们按照方法所述，对所有 Ortho-K 镜片使用者的左眼结膜微循环进行观察、频繁重新聚焦和录像，无论镜片是否在原位。以类似的方式对匹配的对照组（非镜片佩戴者）进行录像和研究。我们分析、量化和汇总每个使用者和对照组的动态和形态特征，并作为严重指数（SI）进行比较。Ortho-K 镜片使用者的 SI（4.18±1.08）与对照组的 SI（1.75±1.39）有显著差异（p≤0.05）。此外，我们观察并录像了近视患者戴上 Ortho-K 镜片后结膜微循环的变化（例如，血流速度、血管直径、形状变化等）。在 11 名 Ortho-K 镜片使用者中，有 8 名显示血流速度有显著百分比变化（p≤0.05），11 名中有 10 名显示血管直径有显著百分比变化（p≤0.05），无论是否佩戴 Ortho-K 镜片。结果清楚地表明，组织重塑引起的明显微血管变化是由 Ortho-K 镜片的物理存在直接引起的。
