Epithelial cell adhesion and haze after photorefractive keratectomy.

orneal haze is the most serious complication of photorefractive keratectomy (PRK) and has been attributed to normal healing processes. 1-3 The prediction of which patients are likely to develop haze is of the utmost importance in the evaluation of patients for PRK. We noted that while removing the epithelium prior to corneal ablation, three distinct types of cornea can be appreciated: 1) normal epithelial adhesion; 2) loose epithelial adhesion, where the epithelium is very easy to remove (" cap-sullorhexis " type), and 3) tight epithelial adhesion that requires significant scraping to remove the epithelium from Bowman's layer. We evaluated the impact of these three types of cornea on postopera-tive refractive results and haze formation. PATIENTS AND METHODS All consecutive patients who underwent excimer laser PRK during January and February 1996 in our center (n=70) participated in this study. The age range of the patients was 20 to 53 years. There were 30 males and 40 females. The average preoperative spherical equivalent was-6.02 diopters (D) (range,-2.00 to-13.00 D). All surgical procedures were done by one of us (I.L.) with the same blunt spatula to remove the corneal epithelium prior to excimer laser ablation. The laser used was the Summit Apex (Summit, Waltham, Mass). During epithelial removal the surgeon graded the epithelial adhesion in grades of 1 to 3: Grade 1—normal epithelial adhesion (when removal of the epithelium was within normal range of epithelial removal; Grade 2—loose epithelial adhesion (when the epithelium was removed relatively easily); and Grade 3—tight epithelial adhesion (when significant scraping was needed to remove the epithe-lium). The same surgical technique and postoperative treatment was used in all patients. RESULTS The minimum follow-up time was 6 months. The average postoperative spherical equivalent was +0.17 D (range-2.00 to +1.75 D). The 70 eyes were divided into three groups. In the first group (43 eyes), normal epithelial adhesion was found. In the second group (14 eyes), loose epithelial adhesion was found. In the third group (13 eyes), tight epithe-lial adhesion was noted. In the tight epithelial adhesion group, most eyes had no haze. In the other two groups, the distribution of haze formation was similar. No difference in postoperative refraction was found between the three groups. DISCUSSION In patients where epithelial adhesion seemed to be tight, there was less tendency to develop corneal haze. No difference in haze formation was noticed between the group of eyes in which epithelial adhesion seemed …