Maldonado M J, Arnau V, Navea A, Martínez-Costa R, Mico F M, Cisneros A L, Menezo J L
Department of Ophthalmology, La Fe University Hospital, Valencia, Spain.
Ophthalmology. 1996 Nov;103(11):1970-8. doi: 10.1016/s0161-6420(96)30400-4.
The purpose of the study is to measure regional distribution differences in corneal haze after excimer laser photorefractive keratectomy for high myopia.
The authors developed computerized gradient edge detectors with which were analyzed digitized anterior slit-lamp photographs of 40 eyes, an average of 21.0 plus or minus 14.5 weeks after photorefractive keratectomy for high myopia (-6 to -22 diopters). A treated area an adjacent untreated area on the anterior corneal surface, each containing six regions, were quantified, and the difference was correlated with various parameters.
Mean differences between scarred and clear areas for haze grade 0.5, 1.0, 2.0, 3.0, and 4.0 were 16.9, 26.6, 42.6, 60.4, and 76.4 gray levels, respectively (rs = 0.96; P = 0.0001). A low but statistically significant correlation between the intended correction and postoperative corneal haze was found (r = 0.33; P = 0.037). The mean coefficient of variation of the amount of opacification within each treated area was 9.4%. This coefficient of variation increased with a longer follow-up time (r = 0.88; P = 0.0001). The difference in the intensity of haze between the center and more peripheral regions over the entrance pupil did not correlate with the attempted correction. However, a strong association between a relatively less severe central corneal haze with respect to more peripheral haze and longer follow-up time was found (r = -0.96; P = 0.0001).
The amount of corneal haze showed a weak positive association with the attempted correction in excimer laser photorefractive keratectomy for high myopia. Corneal haze appeared fairly uniformly distributed within the ablation zone, but a more heterogeneous distribution was found with a longer follow-up time. Furthermore, later postoperative examinations disclosed a clear trend toward diminishing central opacification relative to peripheral regions over the entrance pupil.
本研究旨在测量准分子激光屈光性角膜切削术治疗高度近视后角膜 haze 的区域分布差异。
作者开发了计算机化梯度边缘检测器，用于分析 40 只眼睛的数字化前房裂隙灯照片，这些眼睛在接受高度近视（-6 至-22 屈光度）的屈光性角膜切削术后平均 21.0±14.5 周。对角膜前表面的一个治疗区域和一个相邻的未治疗区域进行量化，每个区域包含六个区域，并将差异与各种参数相关联。
haze 等级为 0.5、1.0、2.0、3.0 和 4.0 的瘢痕区域和清晰区域之间的平均差异分别为 16.9、26.6、42.6、60.4 和 76.4 灰度级（rs = 0.96；P = 0.0001）。发现预期矫正与术后角膜 haze 之间存在低但具有统计学意义的相关性（r = 0.33；P = 0.037）。每个治疗区域内混浊量的平均变异系数为 9.4%。该变异系数随随访时间延长而增加（r = 0.88；P = 0.0001）。入瞳中心和周边区域之间 haze 强度的差异与尝试的矫正无关。然而，发现相对于周边 haze，中央角膜 haze 相对较轻与较长随访时间之间存在强关联（r = -0.96；P = 0.0001）。
在准分子激光屈光性角膜切削术治疗高度近视中，角膜 haze 的量与尝试的矫正呈弱正相关。角膜 haze 在消融区内分布相当均匀，但随访时间延长时发现分布更不均匀。此外，术后后期检查显示出相对于入瞳周边区域，中央混浊有明显减轻的趋势。
