Maloney R K, Friedman M, Harmon T, Hayward M, Hagen K, Gailitis R P, Waring G O
Emory University, Department of Ophthalmology, Atlanta, GA 30322.
Ophthalmology. 1993 Apr;100(4):542-9. doi: 10.1016/s0161-6420(93)31609-x.
The authors developed an erodible mask delivery system for the argon-fluoride 193-nm excimer laser, which offers the possibility of correcting hyperopia and astigmatism as well as myopia.
Masks were made of polymethylmethacrylate on a quartz window, with intended corrections for myopia and hyperopia of 2.5 and 5 diopters (D). Ablations using the mask and control ablations using an expanding diaphragm were performed in 30 eyes of 15 pigmented rabbits with an Excimed UV200 laser (Summit Technology, Inc, Waltham, MA). The rabbits were followed for 134 days with regular biomicroscopy and retinoscopic examination by two observers.
Ablations with the mask to correct myopia were successful and produced stable corrections, although the higher-power mask produced undercorrections. Hyperopic masks produced paradoxic myopic corrections, possibly due to the lack of a transition zone at the edge of the mask. Corneas ablated with the mask had less sub-epithelial haze than those ablated with the diaphragm at all examinations. Results of histopathologic examination showed epithelial hyperplasia over the ablation zone in all eyes. Dichlorotriazinyl aminofluorescein collagen staining showed subepithelial new collagen in all eyes, but there was no relation between the depth of ablation at any point on the cornea and the amount of new collagen deposited there.
Myopic ablations are feasible with the erodible mask, although additional calibration is needed. Hyperopic ablations were unsuccessful with the current design. Corneas ablated with the mask may be clearer than corneas ablated with the diaphragm, possibly due to a smoother ablated surface. Regression of effect after laser ablation in the rabbit model is likely due more to epithelial hyperplasia than to stromal remodeling.
作者研发了一种用于氩氟化物193纳米准分子激光的可蚀性掩膜递送系统，该系统为矫正远视、散光以及近视提供了可能性。
在石英窗上用聚甲基丙烯酸甲酯制作掩膜，预期矫正近视和远视的度数分别为2.5和5屈光度（D）。使用掩膜进行消融以及使用扩张光阑进行对照消融，在15只色素沉着兔的30只眼中使用Excimed UV200激光（Summit Technology公司，马萨诸塞州沃尔瑟姆）进行操作。由两名观察者通过定期生物显微镜检查和视网膜镜检查对兔子进行134天的随访。
用掩膜矫正近视的消融是成功的，并产生了稳定的矫正效果，尽管高功率掩膜产生了欠矫。远视掩膜产生了反常的近视性矫正，可能是由于掩膜边缘缺乏过渡区。在所有检查中，用掩膜消融的角膜比用光阑消融的角膜具有更少的上皮下混浊。组织病理学检查结果显示，所有眼睛的消融区均有上皮增生。二氯三嗪基氨基荧光素胶原染色显示所有眼睛的上皮下均有新的胶原形成，但角膜上任何一点的消融深度与在该处沉积的新胶原量之间没有关系。
使用可蚀性掩膜进行近视消融是可行的，尽管需要额外的校准。当前设计的远视消融未成功。用掩膜消融的角膜可能比用光阑消融的角膜更清晰，这可能是由于消融表面更光滑。在兔模型中激光消融后效果的消退可能更多是由于上皮增生而非基质重塑。
