Long-term follow-up of photorefractive keratectomy for myopia: Comparative study of excimer lasers.

PURPOSE: To compare the long-term results of photorefractive keratectomy (PRK) for low to moderate myopia performed using a broad-beam laser system or a scanning-slit laser system. SETTING: Department of Ophthalmology, University of Helsinki, Helsinki, Finland. DESIGN: Case-control study. METHODS: This follow-up study comprised eyes with myopia (-1.25 to -7.00 diopters [D]) or myopic astigmatism (astigmatism lower than -2.50 D) corrected by PRK using a broad-beam (Visx) or scanning-slit (Nidek) laser. Follow-up included a visit at 3 months and at more than 8 years. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and manifest refraction were recorded. RESULTS: The broad-beam group comprised 27 eyes and the scanning-slit group, 34 eyes. At the last postoperative follow-up, the UDVA was 0.0 or better in 55% of eyes in the broad-beam group and 65% of eyes in the scanning-slit group. The CDVA was 0.0 or better in all eyes in the broad-beam group and 96% of eyes in the scanning-slit group. Regarding predictability, 48% and 73% of the eyes, respectively, were within ±0.50 D of the intended spherical equivalent refraction. There were no statistically significant differences between the 2 laser groups in any preoperative or postoperative parameter. CONCLUSION: There were no significant differences in UDVA, CDVA, or SE after PRK for low to moderate myopia between the broad-beam laser system and the scanning-slit laser system. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Seven-year follow-up of LASIK for myopia.

PURPOSE: To assess the long-term refractive results, subjective parameters, and late sequelae of LASIK. METHODS: A retrospective follow-up study was conducted on 38 eyes of 21 patients (17 with bilateral treatment and 4 with unilateral treatment) who had LASIK surgery between 1999 and 2000. Laser ablations were done with an excimer laser (VISX STAR and STAR S2). Follow-up was 2 months, 2 years, and > 7 years postoperatively. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, indirect ophthalmoscopy, and wavefront analysis were measured at the last follow-up and a questionnaire was answered. RESULTS: Postoperatively, BSCVA < or = 0.0 (logMAR) was obtained in 91%, 100%, and 89% of eyes at 2 months, 2 years, and at last follow-up, respectively. Postoperative spherical equivalent refraction within +/- 0.50 diopters (D) was obtained in 75%, 63%, and 42% of eyes at 2 months, 2 years, and 7 to 8 years, respectively. At 2 months and 2 years, 83% of eyes were within +/- 1.00 D, which decreased to 42% at 7 to 8 years. Mean spherical equivalent refraction at 2 months was -0.41 D, at 2 years -0.57 D, and at 7 to 8 years continued to decrease to -1.38 D. Patient satisfaction was high--100% of patients would have LASIK again. CONCLUSIONS: LASIK outcomes tend to shift toward undercorrection over time. Postoperative ectasia was not noted 7 to 8 years after LASIK. All patients were satisfied with the postoperative results although emmetropia was not reached.

Excimer laser refractive correction of myopia after episcleral buckling for rhegmatogenous retinal detachment.

PURPOSE: To evaluate the long-term effects of excimer laser treatment for ametropia after surgical treatment of rhegmatogenous retinal detachment (RRD) with scleral buckles. SETTING: Helsinki University Eye Hospital, Helsinki, Finland. METHODS: Ten patients (10 eyes) who had 1 or more surgeries for RRD followed by refractive surgery for myopia were retrospectively enrolled in this study and were examined after excimer laser refractive surgery. Photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) was performed using a Star S2 excimer laser system (Visx). The best spectacle-corrected visual acuity (BSCVA), refraction, degree of anisometropia, and topographical changes were evaluated before and after the surgeries. RESULTS: All patients were free of asthenopic symptoms after refractive surgery. At the end of the follow-up, a mean of 67 months +/- 14 (SD) after refractive surgery, 6 patients were within +/-1.0 diopter of the intended correction. Compared with previously reported cohorts of myopic patients, the achieved refraction in patients who previously had a scleral buckling procedure was worse. The postoperative refraction was stable, and corneal topography did not show induced scar formation, keratectasia, or irregular astigmatism. After refractive surgery, the BSCVA improved 1 Snellen line in 3 patients and 2 lines in 1 patient. One patient lost 1 Snellen line and another patient lost 2 lines. Four patients showed no changes. New retinal complications were not observed. CONCLUSIONS: In the long-term, PRK and LASIK were safe methods for the treatment of myopia in RRD patients after scleral buckling. The predictability of myopic LASIK/PRK may be worse than generally reported in myopic cohorts.

Phototherapeutic keratectomy for epithelial irregular astigmatism: an emphasis on map-dot-fingerprint degeneration.

PURPOSE: To study the changes in irregular astigmatism in patients with recurrent corneal erosion syndrome due to map-dot-fingerprint degeneration and to demonstrate that both symptomatic and asymptomatic map-dot-fingerprint degeneration/recurrent corneal erosion syndrome may be related to irregular astigmatism, which can effectively be corrected by phototherapeutic keratectomy (PTK) or standard spherical photorefractive keratectomy (PRK). METHODS: Eleven eyes with irregular astigmatism related to map-dot-fingerprint degeneration/recurrent corneal erosion syndrome with and without changes at the slit-lamp microscope were treated with PTK or spherical PRK, which was performed with a VISX S2 or S4 excimer laser. All eyes underwent videokeratography performed pre- and postoperatively using either the Tomey TMS-2N Topographic Modeling System or EyeSys Technologies Corneal Analysis System 2000. RESULTS: Mean pre- and postoperative best spectacle-corrected visual acuity (BSCVA) was -0.18 +/- 0.14 logMAR and 0.04 +/- 0.04 logMAR, respectively. This improvement in BSCVA was statistically significant. The mean gain in Snellen lines was 2.4 +/- 2.1. Preoperative corneal videokeratography showed irregular astigmatism with an elevation pattern that was corrected in all eyes despite the fact that no astigmatic photorefractive correction was performed. CONCLUSIONS: Following PTK, eyes with irregular astigmatism related to map-dot-fingerprint degeneration showed significant improvement in BSCVA and correction of irregular astigmatism as revealed by videokeratography. This study shows that irregular astigmatism can be exclusively of epithelial origin and in some eyes abnormal corneal epithelium may create optical aberrations. This possibility should be taken into account when, for example, wavefront-guided stromal photoablation procedures are being planned.