Chen S, Wang I J
Department of Ophthalmology, Provincial Hsin-Chu Hospital, Taiwan.
J Refract Surg. 1999 Nov-Dec;15(6):668-72. doi: 10.3928/1081-597X-19991101-11.
To evaluate the difference in tear film break-up between normal eyes and eyes after photorefractive keratectomy (PRK) and its impact on quality of vision in PRK eyes.
Seventy-seven normal eyes and 76 eyes with no ocular pathology except refractive error that had PRK were enrolled. Tear film break-up time was determined under slit-lamp microscopy with fluorescent staining. Two videokeratographs (TMS-1) were taken before and immediately after tear film break-up. Surface asymmetry index, surface regularity index, and subtractive maps were analyzed to evaluate corneal topographic changes before and after tear film break-up.
The distribution of tear film break-up in the central cornea was different in PRK eyes than in normal eyes (P < .0001). Distributions of tear film break-up after PRK were localized more in the upper and lower temporal regions than in normal eyes; incidence of tear film break-up in the central cornea was decreased. There were no significant differences in tear film break-up between normal eyes and eyes after PRK (P = .69). Twelve PRK patients (24 eyes, 32%) experienced fluctuation of vision and fatigue during normal activities after PRK. We divided eyes after PRK into two groups (with and without fluctuation of vision) and found a statistically significant difference in surface asymmetry index before tear film break-up between the two groups (P = .0092).
The distribution of tear film break-up is changed after PRK. Eyes after PRK experienced more fluctuation of vision than normal eyes.
评估正常眼与准分子激光原位角膜磨镶术（PRK）后眼的泪膜破裂差异及其对PRK术后眼视力质量的影响。
纳入77只正常眼和76只除屈光不正外无眼部病变且接受过PRK的眼。在裂隙灯显微镜下用荧光染色法测定泪膜破裂时间。在泪膜破裂前及破裂后立即进行两次角膜地形图检查（TMS-1）。分析表面不对称指数、表面规则指数和减影图，以评估泪膜破裂前后角膜地形图的变化。
PRK术后眼中央角膜的泪膜破裂分布与正常眼不同（P <.0001）。PRK术后泪膜破裂分布更多地集中在颞上和颞下区域，而非正常眼；中央角膜泪膜破裂的发生率降低。正常眼与PRK术后眼的泪膜破裂情况无显著差异（P =.69）。12例PRK患者（24只眼，32%）在PRK术后正常活动期间出现视力波动和疲劳。我们将PRK术后眼分为两组（有和无视力波动），发现两组泪膜破裂前表面不对称指数存在统计学显著差异（P =.0092）。
PRK术后泪膜破裂分布发生改变。PRK术后眼比正常眼经历更多的视力波动。
