One-year results of photorefractive keratectomy and laser in situ keratomileusis for myopia using a 213 nm wavelength solid-state laser

PURPOSE: To study the long-term results of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) in low to moderate myopic corrections using the Pulzar Z1 system (CustomVis), a 213 nm wavelength solid-state laser. SETTING: University refractive surgery center. METHODS: This prospective noncomparative case series comprised 20 patients (40 eyes) who had refractive surgery using the Pulzar Z1 laser system. Manifest refraction, uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), safety, predictability, stability, and confocal microscopy images were evaluated. RESULTS: Ten patients (20 eyes) had PRK and 10 patients (20 eyes) had LASIK. The mean follow-up was 13.9 months +/- 1.1 (SD) (range 12 to 17 months) and 14.6 +/- 1.2 months (range 12 to 18 months) in the PRK group and LASIK group, respectively. No eye lost a line of Snellen BSCVA during the follow-up period; 2 eyes (10%) gained 2 Snellen lines. There was a statistically significant decrease in spherical equivalent manifest refraction postoperatively in both groups (P<.05). Refractive stability was obtained during the first postoperative month and remained stable during the follow-up period, with no significant changes between any interval in both groups (P>.05). At the last follow-up, 95% of all eyes were within +/-1.00 diopter of emmetropia. No late postoperative complications were observed. CONCLUSION: Refractive surgery using the Pulzar Z1 213 nm wavelength solid-state laser was a safe, effective procedure in the treatment of low to moderate myopia.     

Laser refractive correction of myopia in visually impaired patients improves visual acuity

Purpose: To retrospectively evaluate the visual and refractive outcome of visually impaired adults treated with refractive surgery (photorefractive keratectomy or laser‐assisted in situ keratomileusis). Methods: We searched a refractive surgery database comprising 1716 mildly visually impaired patients [best spectacle‐corrected visual acuity (BSCVA) on a logMAR scale ≤ ?0.1 (Snellen ≤ 0.8)] who had undergone either PRK or LASIK (n = 96). PRK patients who had visits at 5–7, 8–13 and 14–24 months postoperatively were selected. Eleven patients and nine PRK control myopic patients were found (cohort 1). From the same database, 41 visually impaired patients and 54 controls who had a postoperative control at 14–24 months postoperatively were chosen. These patients formed cohort 2. Results: Preoperatively, in cohort 1, the mean BSCVA on a logMAR scale was ?0.15 ± 0.13 (Snellen 0.73 ± 0.16) in visually impaired patients and 0.04 ± 0.02 (Snellen 1.11 ± 0.17) in myopic controls. At 14–24 months postoperatively, the mean BSCVA improved to 0.05 ± 0.04 (Snellen 1.13 ± 0.10) in visually impaired patients and 0.05 ± 0.08 (Snellen 1.13 ± 0.21) in control patients. In cohort 2, preoperatively the mean BSCVA on a logMAR scale was ?0.15 ± 0.12 (Snellen 0.74 ± 0.14) in visually impaired patients and 0.01 ± 0.03 (Snellen 1.04 ± 0.10) in myopic controls. At 14–24 months postoperatively, the mean BSCVA improved to 0.02 ± 0.07 (Snellen 1.06 ± 0.16) in visually impaired patients and 0.06 ± 0.06 (Snellen 1.15 ± 0.16) in control patients. Conclusion: Refractive surgery improves BSCVA in visually impaired patients, possibly through plastic changes in the visual cortex. Consequently, refractive surgery may be used successfully for the treatment of visually impaired adults to enhance their visual acuity.     

Clear lens extraction with intraocular lens followed by photorefractive keratectomy or laser in situ keratomileusis

OBJECTIVE: To study photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) after clear lens extraction (CLE) with intraocular lens (IOL) implantation for hyperopia or astigmatism. DESIGN: Retrospective, noncomparative interventional case series. PARTICIPANTS: Sixty-five eyes (55 subjects) had CLE with posterior chamber IOL implants for hyperopia up to 12.25 diopters (D); 31 eyes were retreated with PRK, and 34 eyes were retreated with LASIK for residual ametropias. INTERVENTION: For PRK and LASIK, the refractive surgery was performed with the slit-scanning excimer laser Nidek EC-5000, Nidek Co., Tokyo, Japan. MAIN OUTCOME MEASURES: Manifest refraction, best-spectacle and uncorrected Snellen visual acuity, haze, and halos were evaluated before surgery and at 1, 3, 6, and 12 months postoperative. RESULTS: Forty-seven eyes were evaluated at the 12-month postoperative examination: 96% of these eyes had spherical equivalents (SE) within +/-2 D of emmetropia, 79% of eyes had SE within +/-1 D of emmetropia and 51% of eyes had SE within +/-0.50 D of emmetropia. Eighty-five percent of the eyes at 12 months postoperative had uncorrected visual acuity of 20/40 or better, and 46% of eyes had uncorrected visual acuity of 20/20 or better. Eighty-seven percent of the eyes at 12 months postoperative had uncorrected visual acuity within 1 Snellen line of their initial best spectacle-corrected visual acuity (BSCVA) before all treatment. No eye lost 2 Snellen lines of BSCVA at 3, 6, or 12 months after PRK or after LASIK. CONCLUSIONS: IOL implantation for CLE, although an invasive technique, resulted in better refractive outcomes without laser-related clinical complications after PRK or LASIK adjustment.     

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.     

Photorefractive keratectomy versus laser in situ keratomileusis: a control-matched study

OBJECTIVE: Photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) outcomes were compared at 1, 3, 6, and 12 months after surgery. DESIGN: Retrospective, nonrandomized, comparative study. PARTICIPANTS: One hundred seven LASIK-treated eyes (58 patients) and 107 PRK-treated eyes (91 patients) having myopia between -1 and -9.50 diopters (D). All LASIK-treated eyes were analyzed retrospectively and matched with PRK-treated eyes having sphere within +/-0.25 D, +/-1 D of cylinder, and +/-7 years of age. INTERVENTION: For PRK and LASIK, the refractive surgery was performed with the slit-scanning excimer laser Nidek EC-5000, (Nidek Co. Tokyo, Japan) MAIN OUTCOME MEASURES: Manifest refraction, best-spectacle and uncorrected Snellen visual acuity, haze, halos, and keratometry were evaluated before surgery and up to 12 months after surgery. RESULTS: Seventy percent of eyes were evaluated at the 12-month postoperative exam. Of these eyes, 83% of LASIK cases and 86% of PRK cases had uncorrected visual acuities of 20/20 or better. Refractions within +/-0.5 D represented 78% of the LASIK eyes and 83% of the PRK eyes at that follow-up. Patients who underwent LASIK reported halos twice as often as patients who underwent PRK using a subjective scale. The odds ratio of high halos for LASIK versus PRK was 3.50 (95% confidence interval, 1.89-6.46; P<0.0001). At 1 month after surgery, 64% of the LASIK eyes were within +/-0.50 D compared with 77% of the PRK eyes. No eye lost 2 Snellen lines of best corrected visual acuity at 6 or 12 months after surgery. Ten PRK eyes (9.3%) and three LASIK eyes (2.8%) were retreated. CONCLUSIONS: PRK and LASIK achieved equal refractive outcomes at all postoperative follow-ups, but LASIK patients were twice as likely to experience halos.     

Recovery of uncorrected visual acuity after laser in situ keratomileusis or photorefractive keratectomy for low myopia

PURPOSE: To compare uncorrected visual acuity and refractive error in patients undergoing photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) between 1 week and 6 months after surgery. METHODS: All eyes underwent PRK or LASIK with the VisX StarS2 excimer laser. We retrospectively analyzed data from 77 random eyes of 77 patients in the PRK group and 76 eyes of 76 patients in the LASIK group. All eyes had a low myopic refractive error (spherical equivalent range, -0.88 diopters (D) to -5.13 D; mean PRK. -2.8 +/- 0.20 D: LASIK, -2.5 +/- 0.22 D). Uncorrected visual acuity and manifest refractive error were evaluated 1 week, 1 month, and 6 months after surgery. RESULTS: Each eye undergoing PRK was paired with an eye undergoing LASIK for a similar level of spherical equivalent. Mean uncorrected visual acuity after 1 week was 0.85 +/- 0.06 (20/25, logMAR 0.12 +/- 0.04) for the PRK group and 1.01 +/- 0.06 (20/20, logMAR 0.01 +/- 0.03) for the LASIK group (p < 0.001). Mean spherical equivalent after 1 week was 0.23 +/- 0.12 D for the PRK group and -0.02 +/- 0.07 D for the LASIK group (p = 0.02). Mean uncorrected visual acuity after 1 month was 1.03 +/- 0.05 (20/20, logMAR 0.02 +/- 0.03) for the PRK group and 1.05 +/- 0.05 (20/20. -0.02 +/- 0.03) for the LASIK group (p = 0.16). Mean spherical equivalent after I month was 0.19 +/- 0.10 D for the PRK group and -0.02 +/- 0.09 D for the LASIK group. This difference was statistically significant (p = 0.02), but was unlikely to be clinically significant. Mean uncorrected visual acuity after 6 months was 1.05 +/- 0.06 (20/20, logMAR -0.01 +/- 0.03) for the PRK group and 1.06 +/- 0.05 (20/20, logMAR -0.14 +/- 0.03) for the LASIK group (p = 0.41). Mean spherical equivalent after 6 months was 0.02 +/- 0.08 D for the PRK group and 0.00 +/- 0.08 D for the LASIK group (p = 0.35). CONCLUSION: Uncorrected visual acuity 1 week after surgery is significantly better in eyes undergoing LASIK than in eyes undergoing PRK. Both procedures provide functional vision by 1 week after surgery. The difference does not relate to refractive error, which was similar between the two groups, but to differences in healing of the epithelium. By 1 month after surgery, there is no difference in mean uncorrected visual acuity between eyes that undergo PRK or LASIK for low myopia.     

Photorefractive keratectomy with mitomycin C versus LASIK in custom surgeries for myopia: a bilateral prospective randomized clinical trial

PURPOSE: To compare photorefractive keratectomy (PRK) with prophylactic use of mitomycin C (MMC) and LASIK in custom surgeries for myopic astigmatism. METHODS: Eighty-eight eyes of 44 patients with a minimum estimated ablation depth of 50 microm were randomized to receive PRK with MMC 0.002% for 1 minute in one eye and LASIK in the fellow eye. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), cycloplegic refraction, slit-lamp microscopy, contrast sensitivity, specular microscopy, aberrometry, and a subjective questionnaire were evaluated. Forty-two patients completed 6-month follow-up. RESULTS: Mean spherical equivalent refraction error before surgery and mean ablation depth were -3.99+/-1.20 diopters (D) and 73.09+/-14.55 microm in LASIK eyes, and -3.85+/-1.12 D and 70.7+/-14.07 microm in PRK with MMC eyes, respectively. Uncorrected visual acuity was significantly better in PRK with MMC eyes 3 months (P=.04) and 6 months (P=.01) after surgery. Best spectacle-corrected visual acuity and spherical equivalent refraction did not differ significantly in the groups during follow-up (P>.05). Significant haze was not observed in any PRK with MMC eye. Mean higher order aberration was lower in PRK with MMC eyes postoperatively compared with LASIK eyes (P=.01). Better contrast sensitivity was observed in PRK with MMC eyes than LASIK eyes (P<.05). The endothelial cell count did not differ significantly between groups (P=.65). In terms of visual satisfaction, PRK with MMC eyes were better rated. CONCLUSIONS: Photorefractive keratectomy with MMC appears to be more effective than LASIK in custom surgery for moderate myopia. During 6-month follow-up, no toxic effects of MMC were evident. Long-term follow-up is necessary to attest its safety.     

Comparison of laser in situ keratomileusis and photorefractive keratectomy results: long-term follow-up

PURPOSE: To compare the results of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) over a 4-year follow-up. SETTING: Miyata Eye Hospital, Miyazaki, Japan. METHODS: This comparative retrospective study comprised 22 eyes (22 patients) that had PRK and 18 eyes (18 patients) that had LASIK. To be included, the patient had to have completed a 4-year follow-up. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), percentage of eyes within +/-0.5 diopter (D) of the targeted refraction, central corneal thickness, and the anterior and posterior corneal elevations were compared between the PRK and LASIK groups. RESULTS: The mean UCVA was significantly better in the LASIK group than in the PRK group at 6 months (P = .0043) and 1 year (P = .0044). At 2 years, there was no significant difference in the mean UCVA between the 2 groups. The mean BSCVA was significantly better in the LASIK group than in the PRK group at 6 months (P<.0001), 1 year (P<.0001), and 2 years (P = .0083). At 3 and 4 years, there was no significant difference in the mean BSCVA between the 2 groups. The percentage of eyes within +/-0.5 D of the targeted refraction was not significantly different between groups at any time. CONCLUSIONS: The superiority of LASIK over PRK in short-term efficacy was not retained 4 years after surgery. The main reasons were a myopic shift and a decline in UCVA at the last follow-up in the LASIK group.     

Refractive surgery for unilateral high myopia in children

PURPOSE: To evaluate the safety and efficacy of refractive surgery in children. METHODS: Pediatric patients with unilateral high myopia who were 9 years of age or older were offered refractive surgery to supplement optical correction. The patients and families were informed that the operation may not improve their best-corrected visual acuity. Photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) was performed on the more myopic eye with the use of topical anesthesia. Cycloplegic refraction, stereopsis, motility, and best-corrected visual acuity were measured before the procedure and at 2 months and 20 months after the procedure. All patients had completed amblyopia therapy before surgery. RESULTS: Fourteen eyes of 14 patients aged 9 to 14 years received refractive surgery. Average age at the time of surgery was 11.9 years (+/-1,6). Average corrected preoperative visual acuity was 20/147 (+/-0.065 in decimals). Average preoperative refraction was -7.96 D (+/-2,16) spherical equivalent. Twenty months after refractive surgery, the uncorrected visual acuity averaged 20/129 (+/-0.08 in decimals) and best-corrected vision averaged 20/121 (+/-0.08 in decimals). Average refraction was -0.46 D (+/-0,58) at 2 months and -0.67 D (+/-0,68) D at 20 months. An average myopic shift in refraction of -0.22 D was found in treated eyes during the 20 months of follow-up; this was not statistically significant (P =.69). Three patients had LASIK and 11 patients had PRK. LASIK patients averaged -0.875 D of myopic shift over 20 months of follow-up. Those with PRK averaged -0.025 D. This difference was not statistically significant (P =.10). The vision of 5 of 14 patients improved 1 or 2 lines after refractive surgery. Two patients who had 20/80 vision preoperatively improved to 20/60. No patients lost any lines of vision. Only 4 patients demonstrated stereopsis preoperatively, and all retained stereopsis postoperatively. No patient gained stereopsis. CONCLUSIONS: LASIK and PRK can be performed safely and effectively in children who are cooperative enough to undergo the procedures with topical anesthesia. Refractive surgery does not improve vision in densely amblyopic eyes but may give modest improvement in those that are mildly amblyopic. No significant complications were encountered aside from a myopic shift over time.     

LASIK in children with hyperopic anisometropic amblyopia

PURPOSE: To evaluate the results of LASIK for hyperopia in pediatric eyes with amblyopia resulting from anisometropia. METHODS: Thirty-two children with anisometropic amblyopia in whom conventional therapy was unsuccessful underwent unilateral LASIK between 1999 and 2005. Mean patient age was 10.3 +/- 3.1 years (range: 4 to 15 years), and mean follow-up was 20.1 +/- 15.1 months (range: 12 to 60 months). At the last follow-up examination, spherical equivalent refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and complications were recorded. RESULTS: Mean preoperative and postoperative manifest spherical equivalent refraction of the treated eyes was 5.17 +/- 1.65 and 1.39 +/- 1.21 diopters (D), respectively (P < .01). Mean UCVA was 0.06 +/- 0.09 (range: 0.01 to 0.5) preoperatively and 0.27 +/- 0.23 (range: 0.05 to 0.8) postoperatively (P < .01). Mean BSCVA was 0.20 +/- 0.17 (range: 0.01 to 0.8) preoperatively and 0.35 +/- 0.25 (range: 0.1 to 1.0) postoperatively (P < .01). Six eyes gained > or = 4 lines of BSCVA, 4 eyes gained 2 to 3 lines, 12 eyes gained 1 line, and 9 eyes were unchanged; only 1 eye lost 1 line of BSCVA due to haze in the flap-stroma interface. None of the patients reported halos or glare. There were no intraoperative or postoperative flap complications. CONCLUSIONS: LASIK seems to be an effective and safe procedure for the management of hyperopic anisometropic amblyopia in select cases. Visual acuity improved in the amblyopic eyes and was associated with decreased anisometropia. The refractive response to hyperopic LASIK in children appears to be similar to that of adults with comparable refractive errors.     

Changes in central corneal thickness after laser in situ keratomileusis and photorefractive keratectomy

PURPOSE: To evaluate changes in corneal thickness after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in eyes with the same preoperative refraction, correlate these changes to postoperative refractive outcomes, and compare corneal healing process in a standardized subset of patients. METHODS: Central corneal thickness was measured by contact ultrasound pachymetry in 14 eyes of 8 patients with preoperative myopia of -6.00 D who had LASIK, and in 14 eyes of 8 patients with the same preoperative refractive error who had PRK. Measurements were taken preoperatively, and 1 week, 3, and 6 months after surgery. Data were evaluated and compared using the paired Student t-test and Pearson correlation coefficient. RESULTS: Mean preoperative central corneal thickness in the LASIK group was 549.14 +/- 37.4 microm, and in the PRK group, 552.64 +/- 34.9 microm. At 1-week postoperatively, mean central corneal thickness in the LASIK eyes was 467.28 +/- 29 microm and in the PRK eyes, 473.85 +/- 39.2 microm; at 6 months, central corneal thickness had increased in both groups compared to the 1-week values; LASIK eyes had a mean central corneal thickness of 481.42 +/- 23.0 microm and PRK, 481.50 +/- 35.3 microm. Mean postoperative refraction after 6 months was -0.48 +/- 0.30 D in the LASIK group and -0.67 +/- 0.35 D in the PRK group. CONCLUSION: Increase in central corneal thickness between 1 week and 6 months postoperatively occurred in both LASIK and PRK eyes, but differences were not statistically significant. No statistically significant differences were found in myopic regression between the two patient groups.     

The safety and efficacy of photorefractive keratectomy after laser in situ keratomileusis

PURPOSE: To determine the safety and efficacy of performing photorefractive keratectomy (PRK) in corneas previously treated with laser in situ keratomileusis (LASIK) surgery. METHODS: Fifteen eyes of 14 patients who had initially received LASIK for the treatment of myopia and compound myopic astigmatism were evaluated. Variables included existence of and/or type of flap complication associated with the original LASIK procedure, refractions before and after (3 and 6 months) PRK, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and the development of complications after PRK such as haze, scarring, double vision, or ghosting. RESULTS: All 15 eyes were available for analysis at 6 months. Eleven eyes had experienced flap complications during the initial LASIK procedure and 4 eyes had experienced complications in the LASIK postoperative period. Characteristics prior to performing PRK included 11 myopic and 4 hyperopic eyes. By 6 months after PRK treatment, 87% of eyes had UCVA > or = 20/40, 53% had > or = 20/25, and 40% had > or = 20/20. All eyes had BSCVA of > or = 20/30, with 73% being > or = 20/20. No eye had lost 2 lines of BSCVA and only 1 eye lost 1 line of BSCVA. Sixty percent of eyes were within 1.0 diopters (D) of emmetropia, and 40% were within 0.5 D of emmetropia. A trend towards undercorrection and surgical induction of astigmatism as confirmed by vector analysis was noted. No eye developed significant haze or scarring. CONCLUSIONS: Photorefractive keratectomy may be a safe procedure to perform in corneas previously treated with LASIK surgery. Results show good reduction of refractive error and improvement of UCVA and BSCVA. A significant undercorrection of astigmatism was attributed to surgically induced astigmatism. Further studies are necessary to determine the long-term safety and stability of outcomes.     

Laser in situ keratomileusis versus lens-based surgery for correcting residual refractive error after cataract surgery

PURPOSE: To evaluate and compare the efficacy and safety of laser in situ keratomileusis (LASIK) versus lens-based surgery (intraocular lens [IOL] exchange or piggyback IOL) for correcting residual refractive error after cataract surgery. SETTING: Private eye center, Salt Lake City, Utah, USA. METHODS: This retrospective study included 57 eyes of 48 patients who had LASIK (28 eyes) or lens-based correction (29 eyes) for residual refractive error after cataract surgery. The visual and refractive outcomes were evaluated at a mean follow-up of 20 to 24 months. RESULTS: In the LASIK group, the mean spherical equivalent (SE) was reduced from -1.62 +/- 0.80 diopters (D) preoperatively to +0.05 +/- 0.38 D postoperatively in myopic eyes and from +0.51 +/- 1.25 D to +0.19 +/- 0.35 D in hyperopic eyes. Ninety-two percent of eyes were within +/-0.50 D of intended correction. In the lens group, the mean SE was reduced from -3.55 +/- 2.69 D preoperatively to -0.20 +/- 0.50 D postoperatively in myopic eyes and from +2.07 +/- 2.38 D to +0.07 +/- 0.85 D in hyperopic eyes. Eighty-one percent of eyes had postoperative SE within +/-0.50 D of the intended correction. The UCVA improved significantly in both groups. No eye lost more than 1 line of BSCVA. With a similar length of follow-up, no significant difference in postoperative SE was found between the 2 groups (P = .453). CONCLUSIONS: The results showed efficacy, safety, predictability, and merits of LASIK and lens-based approaches for correcting different types of residual refractive error after cataract surgery.     

Laser in situ keratomileusis for refractive error after cataract surgery

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) to correct refractive error following cataract surgery. SETTING: The Eye Institute, Sydney, Australia. METHODS: This retrospective study reviewed 23 eyes (19 patients; 10 female, 9 male) treated with LASIK for refractive error following cataract surgery. The Summit Apex Plus and Ladarvision excimer laser and the SKBM microkeratome were used. The mean age was 63.5 years (range 50 to 88 years). The mean length of follow-up was 8.4 months (range 1 to 12 months) and mean interval between cataract surgery and LASIK was 12 months (range 2.5 to 46 months). RESULTS: The mean preoperative spherical equivalent refraction (SEQ) for myopic eyes was -3.08 +/- 0.84 diopters (D) (range -4.75 to -2.00 D) and for hyperopic eyes was +1.82 +/- 1.03 D (range +0.75 to +3.00 D). The mean improvement following LASIK surgery was greater for myopic than hyperopic eyes (myopic, 2.54 +/- 1.03 D versus hyperopic, 1.73 +/- 0.62 D; P=.033). The percentage of patients within +/-0.5 D of intended refraction post-LASIK surgery was 83.3% for myopic eyes and 90.9% for hyperopic eyes and all eyes were within +/-1.0 D of intended (P<.001). The percentage of eyes with uncorrected visual acuity of 20/40 or better in the myopic group improved from none preoperatively to 91.7% postoperatively (P<.001) and in the hyperopic group improved from 27.3% preoperatively to 90.9% postoperatively (P=.008). No eyes lost 2 or more lines of best corrected visual acuity. CONCLUSION: Laser in situ keratomileusis appears to be effective in correcting refractive error following cataract surgery. Longer-term studies are required to determine refractive stability.     

准分子激光原位角膜磨镶术治疗儿童高度远视屈光参差性弱视的效果

目的评价准分子激光原位角膜磨镶术（LASIK）矫治儿童高度远视性屈光参差的安全性、有效性、可预测性和稳定性,并探讨其对术后弱视治疗效果的影响。方法采用前瞻性自身对照法观察42例高度远视屈光参差性弱视儿童病例,年龄范围6～14岁。使用SVS Apex plus准分子激光系统（其中联合L型mask盘矫正单纯远视9例,联合P型mask盘矫正远视合并散光12例）及鹰视世纪波准分子激光系统（21例）,在局部麻醉或全身麻醉下对患儿高度远视眼行LASIK,术后进行弱视治疗。术后对视力、屈光度和双眼视功能进行分析。随访时间6～24个月。结果矫治屈光度数为＋3．00-＋7．50D,术后2年66．6％术眼残余屈光度数在预计矫正屈光度数±1．00D的范围内。术后随访发现睫状肌麻痹下等值球镜屈光度数波动范围为＋0．99～＋0．67D。最佳戴镜矫正远、近视力均不丢失。术后2年平均最佳戴镜矫正远视力为0．40±0．28,平均最佳戴镜矫正近视力为0．78±0．39。经规范弱视治疗,双眼不等像、同时视、融合、立体视及隐斜均得以改善。结论对患有高度远视性屈光参差且不能耐受戴镜矫治的儿童,采用LASIK矫治屈光参差是安全、有效的,具有良好的可预测性和稳定性,且这一手术有助于提高高度远视屈光参差性弱视的治愈率。     

Topographic centration of ablation after LASIK for myopia using the CustomVue VISX S4 excimer laser

PURPOSE: To determine the ablation centration, efficacy, predictability, and safety of CustomVue LASIK using the VISX S4 excimer laser for the treatment of myopia and myopic astigmatism. METHODS: A retrospective review of 20 myopic eyes of 12 patients treated with LASIK CustomVue VISX S4 was conducted. Corneal topography was used to determine ablation centration. Primary outcome variables including manifest refraction, best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), and complications were evaluated at 3 months postoperatively. RESULTS: Mean decentration (from ablation zone to entrance pupil) was 0.23 +/- 0.08 mm at 3 months postoperatively. No eyes were decentered > 0.5 mm. Preoperatively, the mean spherical equivalent refraction was -4.81 +/- 11.39 diopters (D) (range: -6.75 to -2.25 D). At 3 months postoperatively, mean spherical equivalent refraction was -0.63 +/- 0.25 D (range: -2.00 to 0.25 D). Nineteen (95%) of 20 eyes had UCVA of 20/40 and 16 (80%) of 20 eyes had UCVA of 20/20 at 3 months postoperatively. Fourteen (70%) eyes were within +/- 0.50 D and 18 (90%) eyes were within +/- 1.00 D of emmetropia. No eye lost > 1 line of BSCVA. CONCLUSIONS: Wavefront-guided LASIK using the CustomVue VISX S4 for myopic eyes results in minimal decentration ablation and effective, predictable, and safe visual outcomes.     

LASIK for myopia with the Zeiss meditec MEL 80

PURPOSE: To prospectively evaluate a new high-speed, small spot-scanner laser for the correction of myopia and myopic astigmatism. METHODS: Seventy-six consecutive eyes with myopia and myopic astigmatism between -1.00 and -8.25 diopters (D) and up to -2.75 D astigmatism underwent LASIK treatment using the MEL 80 laser (Carl Zeiss Meditec, Jena, Germany). Parameters evaluated were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), residual refractive error, regression of correction, and aberrometry. RESULTS: Mean preoperative BSCVA was 20/20, which improved to 20/18 postoperatively. Postoperative UCVA was 20/20 at 1 month and 20/18 at 1 year. Uncorrected visual acuity > or = 20/20 was achieved in 58 (83%) of 70 eyes at 1 month and in 60 (88%) of 68 eyes at 1 year. The average refractive error before LASIK was -4.41 +/- 1.98 D. The mean residual refractive error was 0.14 +/- 0.31 D at 1 month and 0.13 +/- 0.30 D at 1 year. At 1-month and 1-year follow-up, respectively, 66 (94%) of 70 eyes and 65 (96%) of 68 eyes were within +/- 0.50 D of intended refractive correction. No eye lost two lines. At 1 month 17% of eyes and at 1 year 13% of eyes gained two lines or more. Between 1-month and 1-year follow-up, 100% of eyes were stable. Mean root-mean-square high order aberration changed from 0.20 microm preoperatively to 0.28 microm postoperatively. CONCLUSIONS: The MEL 80 is effective and safe in the treatment of myopia and myopic astigmatism.     

Nomogram adjustment of laser in situ keratomileusis for myopia and myopic astigmatism with the Alcon LADARVision system

PURPOSE: To evaluate the visual and refractive results of conventional (non-wavefront) laser in situ keratomileusis (LASIK) for treatment of myopia and myopic astigmatism using the Alcon LADARVision 4000 excimer laser system and nomogram adjustment techniques. METHODS: A retrospective analysis of 499 eyes that had LASIK for myopia and myopic astigmatism was performed. Preoperative manifest spherical equivalent refraction ranged from -0.43 to -6.00 D and preoperative astigmatism ranged from 0 to -4.75 D. Patients were evaluated during 3 months following surgery. RESULTS: One month after surgery, 72% of eyes examined (298/415 eyes) had uncorrected visual acuity (UCVA) of 20/20 or better. Three months after surgery, 83% of eyes examined (216/261 eyes) had UCVA of 20/20 or better. One and three months after surgery, 82% and 83% of eyes, respectively, were within +/-0.50 D of attempted correction; 97% of eyes were within +/-1.00 D at both 1 and 3 months. No eye lost more than 1 line of best spectacle-corrected visual acuity (BSCVA) at 3 months after surgery. At the 3-month examination, 83% of eyes had UCVA better than or equal to preoperative BSCVA. CONCLUSIONS: Conventional LASIK to correct myopia and myopic astigmatism was safe and effective using the Alcon LADARVision 4000 excimer laser system. Outcomes were substantially improved throughout development of an accurate nomogram, derived from continually updated regression analysis of previous refractive results.     

Wavefront-guided photorefractive keratectomy for myopia and myopic astigmatism

PURPOSE: To evaluate the results of wavefront-supported customized ablation (WASCA) in eyes treated with photorefractive keratectomy (PRK) to correct spherical myopia and myopic astigmatism. METHODS: One-hundred fifty eyes of 104 patients (mean age 33.4 +/- 4.4 years) were included in the study. An Asclepion Shack-Hartmann wavefront aberrometer was used to assess lower and higher order refractive aberrations of eyes, and customized PRK treatments were carried out using the Asclepion-Meditec MEL 70 G-Scan excimer laser. Follow-up time was 6 months. RESULTS: The mean preoperative spherical equivalent refraction was -4.02 +/- -1.04 D, and mean uncorrected visual acuity (UCVA) was 0.06 +/- 0.02. Postoperatively, mean UCVA was 1.04 (better than 20/20), mean best spectacle-corrected visual acuity was 1.22 (20/16), and average spherical equivalent refraction was -0.12 D; 98.6% (148 of 150 eyes) were within +/-0.50 D of intended refraction, and 100% were within +/-1.00 D. Concerning safety, in 71.1% of eyes (107 of 150) BSCVA was the same as preoperatively, and in 8.2% (11 of 150) it increased by two or more Snellen lines. None of the eyes lost two or more lines of BSCVA. The root mean square value for higher order aberrations increased 1.4 times following PRK. CONCLUSIONS: WASCA-guided PRK was efficacious, safe and predictable; BSCVA may be improved by the WASCA method compared to results achievable with a traditional PRK technique, in spite of an increase in the root mean square value for higher-order aberrations.     

Wavefront-guided laser in situ keratomileusis with the Bausch & Lomb Zyoptix system

PURPOSE: To evaluate the clinical results of wavefront-guided laser in situ keratomileusis (LASIK) with the Zyoptix system. METHODS: Twelve patients (24 eyes) underwent wavefront-guided LASIK with the Bausch & Lomb Zyoptix system. Uncorrected and best spectacle-corrected visual acuity and manifest refraction were measured at postoperative day 1, week 1, and months 1 and 3. A subjective vision quality questionnaire evaluated light sensitivity, dryness, tearing, glare, halos, ghost images, and difficulties in night driving, preoperatively and 3 months postoperatively. RESULTS: Preoperatively, mean sphere was -3.70 +/- 2.33 D (range -0.50 to -8.00 D), mean cylinder was -0.90 +/- 0.98 D (range 0 to -3.00 D), and mean spherical equivalent refraction was -4.15 +/- 2.16 D (range -1.38 to -8.25 D). Three-month postoperative spherical equivalent refraction was within +/- 0.50 D of emmetropia in 17 eyes (70.8%) and within +/- 1.00 D in 22 eyes (91.7%). At 3 months postoperatively, no eyes lost any lines of BSCVA and eight eyes (33.3%) gained 2 lines. The ratio of postoperative BSCVA to preoperative BSCVA (safety) was 1.05 +/- 0.09 (range 1.00 to 1.20) at 1 month and 1.07 +/- 0.10 (range 1.00 to 1.29) at 3 months. The ratio of postoperative UCVA to preoperative BSCVA (efficacy) was 0.96 +/- 0.12 (range 0.80 to 1.20) at 1 month and 0.95 +/- 0.12 (range 0.8 to 1.2) at 3 months. The subjective vision quality questionnaire revealed less tearing, fewer halos, and less difficulty in night driving after wavefront-guided LASIK. Comparison of higher order optical aberrations before and after surgery was not done. CONCLUSIONS: Wavefront-guided LASIK with the Bausch & Lomb Zyoptix system was safe and effective in correcting low to moderate myopic refractive error.