Department of Ophthalmology, Yeouido St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Cornea. 2014 Jan;33(1):82-90. doi: 10.1097/ICO.0000000000000001.
We evaluated light exposure-induced dry eye syndrome by investigating the phototoxic effects of an operating microscope on the ocular surface and tear film in rabbits.
Sixty eyes of 30 rabbits were divided into 3 groups based on the intensity of light exposure received from an operating microscope: Control group, no exposure to light; group A, 40,000-lx intensity for 30 minutes; and group B, 100,000-lx intensity for 30 minutes. To evaluate the potential damage to the ocular surface and tear film, Schirmer tests, rose bengal staining, and conjunctival impression cytology were performed before the light exposure and at 1, 3, and 5 days afterward. In addition, the expression of interleukin 1-beta was analyzed in tear samples. The expression of mucin 5AC was evaluated using immunofluorescence staining, and periodic acid-Schiff staining was conducted on conjunctival tissues. Corneal and conjunctival tissues were observed by means of electron microscopy.
Potential damage to the ocular surface and tear film was found in the light-exposed groups as evidenced by decreased aqueous tear production, devitalized corneal and conjunctival epithelial cells, squamous metaplasia of conjunctival epithelial cells, decreased conjunctival goblet cell density, decreased expression of mucin 5AC, ultrastructural cellular damage to corneal and conjunctival tissues, and increased interleukin 1-beta expression in tears. This damage was more noticeable in group B than in group A (P < 0.05).
Light exposure from an operating microscope had phototoxic effects on the ocular surface and tear film in this in vivo experiment. These changes seemed to intensify as the intensity of the light increased. Therefore, excessive light exposure during ophthalmic procedures could be a pathogenic factor in dry eye syndrome after a surgery is performed.
通过研究手术显微镜对兔眼表面和泪膜的光毒性作用，评估光暴露引起的干眼症。
30 只兔的 60 只眼根据手术显微镜接受的光强度分为 3 组：对照组，不暴露于光线下；组 A，40000lx 强度 30 分钟；组 B，100000lx 强度 30 分钟。为评估对眼表面和泪膜的潜在损伤，在光暴露前和光暴露后 1、3 和 5 天进行 Schirmer 试验、玫瑰红 Bengal 染色和结膜印片细胞学检查。此外，分析泪液样本中白细胞介素 1-β的表达。使用免疫荧光染色评估粘蛋白 5AC 的表达，并用过碘酸希夫染色对结膜组织进行染色。通过电子显微镜观察角膜和结膜组织。
暴露于光线下的组中发现眼表面和泪膜的潜在损伤，表现为房水产生减少、角膜和结膜上皮细胞失活、结膜上皮细胞鳞状化生、结膜杯状细胞密度降低、粘蛋白 5AC 表达减少、角膜和结膜组织超微结构细胞损伤以及泪液中白细胞介素 1-β表达增加。与组 A 相比，组 B 中的损伤更为明显（P<0.05）。
在这项体内实验中，手术显微镜的光照射对眼表面和泪膜具有光毒性作用。随着光强度的增加，这些变化似乎加剧。因此，眼科手术过程中过度的光暴露可能是手术后干眼症的致病因素。
