Photorefractive corneal procedures in patients with systemic diseases

This retrospective, non-randomized, non-comparative clinical study included 14 eyes of 7 patients who underwent laser in situ keratomileusis [LASIK] and 4 eyes of 4 patients who underwent photorefractive keratectomy [PRK] as a primary procedure to correct their myopia and astigmatism. All patients had a history of controlled systemic autoimmune diseases including rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, psoriasis and Behcet's disease. The visual acuity, refraction, keratometric readings, slit-lamp biomicroscopy and corneal topography were assessed in these eyes at regular follow-up periods of 1, 3 and 6 months postoperatively. The mean pre-LASIK/PRK spherical equivalent [SE] decreased from -4.01 D +/- 1.51 standard deviation [SD] preoperatively to - 0.31 D +/- 0.47 SD by the end of the sixth postoperative month which was statistically significant. The mean preoperative uncorrected visual acuity [UCVA] was less than 20/200. Six months after LASIK/PRK procedure, UCVA was 20/25 that was also statistically significant. Retreatment for regression was necessary in 5 [27.7%] eyes at variable periods of time following the primary procedure. The procedures were done easily without any unusual intraoperative complications. The postoperative symptom suggestive of dry eye were not more than usual with the exception of one eye which developed exaggerated symptoms

Decision making in superficial keratectomy: manual vs phototherapeutic techniques

Superficial keratectomy is the surgical removal of subepithelial fibrous membranes and/or anterior corneal opacities that occur in a variety of corneal degenerative and dystrophic conditions. Superficial keratectomy may be performed manually or by phototherapeutic ablation with a 193 nm excimer laser. Manual superficial keratectomy is particularly applicable for disorders of the epithelium and basement membrane zone where mechanical removal is technically easy and is not associated with significant postoperative scaring. While phototherapeutic keratectomy has afforded the ability to remove anterior corneal pathology that is not easily amenable to manual keratectomy, this does not automatically make phototherapeutic keratectomy the surgical treatment of choice for every anterior corneal disorder. Appropriate recommendations regarding the treatments of choice can only be made after analyzing the horizontal [optical zone, paracentral zone, peripheral zone] and vertical [pre-Bowman's, Bowman's anterior stromal, stromal] distribution of the pathology, the pattern [nodular, segmental, diffuse, complete] of the pathology, the applicability of manual and phototherapeutic techniques to the pathology, and the functional [visual, nonvisual] objectives of therapy. Sound clinical evaluation and judgment will maximize the opportunity for excellent care afforded by having both of these treatment modalities in the therapeutic armamentarium for anterior corneal disorders

Changes in corneal topography after excimer laser photorefractive keratectomy for low and moderate myopia

Computer assisted analysis of corneal topography was performed in 39 eyes [20 patients] during follow up after excimer laser photorefractive keratectomy by using keracor 116 excimer laser with multizone mode program with pretreatment zone 50% for myopia from -1.5 to -5.5 diopters [spherical], with -0.25 to -2.0 diopters [astigamtism]. The most frequent undesirable finding was decentralization, also central island was noted in some cases. In spite of these findings visual outcome was satisfactory

Corneal endothelium after photorefractive keratectomy

This study included 30 eyes of 22 patients. They underwent excimer photorefractive keratectomy for the correction of myopic errors ranging from -2.0 to 6.0 diopters [mean 4.8]. The corneal endothelium was studied preoperatively, 3 and 9 months after the procedure. There was no statistically significant difference between the endothelial cell count before the procedure and 3 or 9 months later. Also, there was no change in cell morphology. This proves that excimer laser photokeratectomy for correction of myopic errors up to -6.0 causes no endothelial cell damage