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Objectives: To describe the refractive results of cataract surgery after photorefractive keratectomy (PRK) for patients with myopia, and to find a more accurate method to predict intraocular lens (IOL) power in these cases., Design: Nonrandomized, retrospective clinical study., Patients and Methods: Nine patients (15 eyes) who underwent cataract surgery after prior PRK to correct myopia were identified. The medical records of both the laser and cataract surgery centers were reviewed., Main Outcome Measures: Eight different keratometric values (K values; measured or calculated) were entered into 3 different IOL calculation formulas: SRK/T, Holladay 1, and Hoffer Q. The actual biometry and IOL parameters were used to predict postoperative refraction, which was compared with the actual refractive outcome. Also, the relative underestimation of the refractive change in corneal dioptric power by keratometry after PRK was calculated., Results: In 7 of 15 eyes, IOL exchange or piggybacking was performed because of hyperopia. Retrospectively, the most accurate K value for IOL calculation was found to be the pre-PRK K value corrected by the spectacle plane change in refraction. Use of the Hoffer Q formula would have avoided postoperative hyperopia in more cases than the other formulas. The mean underestimation of the change in corneal power after PRK varied from 42% to 74%, depending on the method of calculation., Conclusion: The predictability of IOL calculation for cataract surgery after PRK can be improved by using a corrected, refraction-derived K value instead of the measured, preoperative K value.

Objective: To evaluate epithelial-stromal interactions in the healing of stromal wounds and the relationship of such interactions to regional variations in healing throughout keratotomy wounds., Methods: Ten radial keratotomy autopsy specimens were studied by using light and transmission electron microscopy., Results: Underneath epithelial plugs, the epithelial-stromal interface was characterized by three adjacent morphological zones: a duplicated basement membrane complex, a zone that resembled Bowman's layer, and a third zone with collagenous fiber orientation parallel to the plugs. Scar tissue orientation was transverse at the base of the plug, and sagittal in deeper wound regions., Conclusions: Basement membrane duplication and a Bowman's layer-like region underneath a plug may result from complicated epithelial-stromal interaction. Asymmetrical organization of the scar, with subepithelial transverse and sagittal deeper scar tissue orientation, may characterize radial keratotomy wound healing, and may relate to variations in final refractive effect.

Objective: To determine regional differences in stromal wound healing morphologic features in long-term radial keratotomy wounds., Methods: Unsutured, semiradial, nonperforating wounds in seven monkeys and 10 human autopsy specimens obtained 3.5 to 52 months after surgery were analyzed using light, transmission, and fluorescent microscopy., Results: Monkeys showed fast healing, whereas all human specimens had one or more incisions containing a superficial epithelial plug. Completely healed wounds in both models had fibroblast orientation and ultrastructural "pseudolamellar" (ie, colinear collagen fiber) continuity across the anterior wound, compared with disorganization of the midposterior scar., Conclusions: Regional differences in healing rates, mechanical factors associated with epithelial plug elimination, intrinsic tissue characteristics, and/or induction of pseudolamellar repair by the epithelial plug may explain variation in healing within an unsutured corneal wound.

We compared corneal wound healing in 25 clear transplants with 26 keratotomy specimens and sutured and unsutured corneal wounds in a monkey model. Monkey wounds healed faster than human wounds, but healing time within the same species varied. Sutured wounds were characterized by subepithelial fibroplasia, recovery of collagen fiber continuity and absence of epithelial plugs. Unsutured wounds had no subepithelial fibroplasia but had fibroblasts and collagen fiber orientation parallel to wounds. Unsutured wounds in corneas containing sutures had subepithelial fibroplasia, and fibroblast orientation and fiber deposition parallel to the wound. Epithelial ingrowth and incarceration of Bowman's layer and/or Descemet's membrane in unsutured wounds appeared to disrupt wound healing. Abnormalities in wound healing in sutured or unsutured wounds are associated with lamellar distortion, a modified inflammatory response, and individual wound healing responses.