Department of Pathology and Laboratory Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA.
Clin Hemorheol Microcirc. 2012;51(1):77-86. doi: 10.3233/CH-2011-1513.
Soft contact lenses are commonly used to improve vision acuity or in cosmetic enhancement. We hypothesize that contact lens use can cause inadvertent damage to either the conjunctival microcirculation via direct vasoocclusion when the lens physically interacts with or damages the underlying vessels, or to the bulbar conjunctiva itself when the lens rests unevenly on the surface of the bulbar conjunctiva. Computer-assisted intravital microscopy was utilized to document (via video recording) and objectively quantify (via image analysis) real-time microvascular abnormalities resulting from changes and vessel remodeling in the conjunctival microcirculation in long-term (>2 yrs) contact lens users (n = 102), with non-users serving as control subjects (n = 29). A severity index (SI)--computed as the arithmetic sum of the abnormalities found in the conjunctival microcirculation in each contact lens user--was established for objective comparison with control subjects and critical interpretation. Contact lens user SI was significantly higher than control SI (user = 6.21 ± 1.26; control = 2.31 ± 1.49; p < 0.05), indicative of severe vasculopathy arising from contact lens use. The users also had significantly wider conjunctival vessel diameter (user = 71.25 ± 12.09 μm; control = 52.20 ± 5.10 μm; p < 0.05). Additional abnormalities, including damaged vessels, hemosiderin deposits (from damaged vessels or injury to the surface of the bulbar conjunctiva), vessel sludging, intermittent blood flow, and vessel tortuosity were commonly found in or adjacent to locations where the contact lens physically rested on the underlying conjunctival vessels. These results strongly suggest that microvascular abnormalities and remodeling changes occurred as a result of the inadvertent physical interaction of the lenses with either the underlying conjunctival vessels or the surface of the bulbar conjunctiva in contact lens users.
软性隐形眼镜通常用于提高视力或进行美容增强。我们假设隐形眼镜的使用可能会导致结膜微循环的意外损伤，原因是镜片与下方的血管直接发生血管阻塞，或者当镜片不均匀地位于球结膜表面时，导致球结膜本身的损伤。我们利用计算机辅助活体显微镜通过视频记录记录并客观量化长期（> 2 年）隐形眼镜使用者的结膜微循环中的血管变化和血管重塑引起的微血管异常（n = 102），并将非使用者作为对照（n = 29）。为了与对照进行客观比较和进行关键解释，建立了一个严重指数（SI）——通过计算每个隐形眼镜使用者的结膜微循环中的异常情况的算术和得出。隐形眼镜使用者的 SI 明显高于对照的 SI（使用者 = 6.21 ± 1.26；对照 = 2.31 ± 1.49；p < 0.05），表明隐形眼镜使用引起严重的血管病变。使用者的结膜血管直径也明显变宽（使用者 = 71.25 ± 12.09 μm；对照 = 52.20 ± 5.10 μm；p < 0.05）。在隐形眼镜物理接触到下方结膜血管或球结膜表面的位置或附近，还经常发现其他异常，包括受损的血管、含铁血黄素沉积（来自受损的血管或球结膜表面的损伤）、血管淤积、间歇性血流和血管扭曲。这些结果强烈表明，在隐形眼镜使用者中，由于镜片与下方的结膜血管或接触镜下的球结膜表面的意外物理相互作用，导致了微血管异常和重塑变化。
