Wavefront-guided treatment of symptomatic eyes using the LADAR6000 excimer laser.

PURPOSE: To evaluate the clinical results of wavefront-guided customized treatment of eyes that underwent previous keratorefractive surgery with clinically significant visual symptoms related to the presence of higher order aberrations, with or without defocus/astigmatism. METHODS: Twenty-eight consecutive eyes of 19 symptomatic patients underwent wavefront-guided custom photorefractive keratectomy (PRK with mitomycin C) to correct low and high order aberrations, using the LADAR-Vision platform. All eyes had manifest refractive spherical equivalent (MRSE) error from 0.00 to -4.25 diopters (D), and high order aberrations root-mean-square (RMS) values >0.80 microm for a 6.0-mm measurement diameter (mean: 1.18 microm). Eyes were examined at 1, 3, and 6 months postoperatively. Uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), MRSE, wavefront measurement of high order aberrations, and patient subjective evaluation were the parameters used to assess the treatment. RESULTS: Six months after treatment, all 28 eyes had an improvement in UCVA compared to preoperative values. Seventeen (60.7%) eyes gained lines of BSCVA (1 to 3 lines) whereas 1 eye lost 1 line. Although the amount of positive defocus was intentionally and empirically undercorrected in this study, MRSE was slightly hyperopic (mean +0.65 D, range: -0.25 to +1.75 D). All eyes showed a reduction in pre-existing high order aberrations, with a mean reduction of 47% (0.62 microm). Spherical aberration reduced the most (mean 60%), coma was reduced by a mean 29%, and all other terms were reduced by a mean 42% compared to preoperative values. Subjectively, all patients but 1 (both eyes treated) noticed a reduction in their pre-existing visual symptoms. Overall, the treatment was considered satisfactory by the patients in terms of visual quality gain. CONCLUSIONS: This series of consecutive treatments of symptomatic eyes indicates wavefront-guided custom ablation is an effective surgical option to reduce visually impairing high order aberrations and related visual symptoms. To avoid the resulting hyperopic shift, some significant nomogram adjustments are necessary, most often when pre-existing positive spherical aberration is present.

First clinical experience with the Alcon LADAR 6000 excimer laser.

PURPOSE: To evaluate the reliability and ergonomics and to assess the first clinical results provided by the new LADAR 6000 excimer laser used to correct myopia and astigmatism, both by conventional and wavefront-guided ablation. METHODS: Seventy-four consecutive eyes from 37 patients underwent LASIK as the first field evaluation protocol of the Alcon LADAR 6000 excimer laser. Forty-six eyes were treated by wavefront-guided ablation to correct a manifest spheroequivalent refractive error (MSRE) of -0.50 to -9.75 diopters (D) (mean: -4.19 D, cylinder range: 0.0 to -3.50 D). Twenty-eight eyes were treated by conventional ablation to correct MSRE of -1.00 to -7.00 D (mean: -3.11 D, cylinder range: 0.0 to -1.75 D). Uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), MSRE, and wavefront measurements were assessed. Follow-up was 3 months for all eyes. RESULTS: Three months after surgery, all eyes were within +/- 1.00 D of intended correction. Forty-three (93.5%) eyes treated with wavefront-guided ablation and 25 (89.3%) eyes treated with conventional ablation were within +/- 0.50 D. All eyes reached > or = 20/25 UCVA. UCVA > or = 20/20 was reached in 45 (97.8%) wavefront-guided eyes and 26 (92.9%) conventional eyes; 37 (80.4%) wavefront-guided eyes and 17 (60.7%) conventional eyes had 20/16 UCVA. None of the eyes treated lost > or = 2 lines of BSCVA. CONCLUSIONS: The LADAR 6000 excimer laser results proved to be at least as accurate, predictable, and safe as the results currently achieved with the LADARVision4000 excimer laser. The improved microscope illumination enhances visibility for better consistency and ease of use. The better ergonomics and software design of this platform improved patient flow.

Expanded range customcornea algorithms for myopia and astigmatism: one-month results.

PURPOSE: To evaluate the early clinical results achieved with an algorithm adjusted for an expanded range of correction in wavefront-guided customized ablation with the LADARVision4000 (Alcon Laboratories Inc, Fort Worth, Tex). METHODS: Fifty-five consecutive eyes from 31 patients underwent wavefront-guided, customablation laser in situ keratomileusis (LASIK) (Hansatome and BD 4000 microkeratomes, LADARWave aberrometer, LADARVision4000 laser system). These were normal myopic and astigmatic eyes that had never been operated on. The spherical equivalent refractive error was +0.30 to -8.13 diopters (D) (mean -4.26 +/- 2.14 D) and the astigmatism ranged from 0 to -3.75 D (mean -0.97 +/- 0.96 D). eyes were treated according to the CustomCornea protocol using the commercial LADARVision4000 platform. Patients were followed for at least 2 months and standard visual measurements were taken and recorded at 1 day and 1, 3, and 6 months after treatment. The results of treatment were assessed using the following parameters: uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA); manifest spherical equivalent refractive error; wavefront measurement of high order aberrations; and subjective reports of visual symptoms by patients. RESULTS: One month after LASIK, the mean manifest spherical equivalent refractive error was -0.18 +/- 0.41 D. Seventy-eight percent and 96% of eyes had manifest spherical equivalent refractive error within +/-0.50 D and +/-1.00 D of attempted correction, respectively, with 78% of eyes with 20/20 or better UCVA. Eyes with 20/16 and 20/12.5 BSCVA were 89% and 36%, respectively (55% and 7% preoperatively). The mean high order aberrations root-mean-square was 0.34 +/- 0.10 microm preoperatively and 0.35 +/- 0.09 microm postoperatively (6.0-mm pupil size). High order aberrations were either reduced, unchanged, or increased by <10% in 58% of eyes. Subjectively, patients reported no visual symptoms and had no complaints regarding the quality of their vision. CONCLUSION: The new optimized algorithm for higher refractive errors appears to be effective in improving BSCVA, and a minority of patients demonstrated an increase in the magnitude of high order aberrations when compared to preoperative aberrometry. A slight spherical equivalent refraction undercorrection will be addressed with future nomogram adjustments.

Wavefront-guided treatment of abnormal eyes using the LADARVision platform.

PURPOSE: To evaluate the clinical results of Alcon LADARVision4000 wavefront-guided customized treatment of eyes with myopia and/or astigmatism, and clinically significant visual symptoms related to the presence of higher order aberrations. METHODS: Seven consecutive abnormal eyes from seven patients underwent wavefront-guided CustomCornea (1 PRK, 6 enhancements after previous LASIK) to correct low and higher order aberrations, using the Alcon LADARVision4000 platform. Eyes were examined at 1 to 3 months after treatment; the longest follow-up examination was used for analysis. Uncorrected and best spectacle-corrected visual acuity, manifest refractive spherical equivalent error, and subjective visual symptoms were measured, as well as wavefront measurement of higher order aberrations. RESULTS: All seven eyes had an improvement in UCVA. One eye gained 2 lines of BSCVA, four eyes gained 1 line, and no eye lost any lines. Manifest refractive spherical equivalent error was slightly hyperopic in all eyes (+0.12 to +1.50 D). All eyes showed a reduction in pre-existing higher order aberrations, ranging between 1% and 48%. Spherical aberration was reduced most (mean 38% reduction), coma was reduced by a mean 14%, and all other terms were reduced by a mean 17% compared to preoperative values. Subjectively, all patients noticed a reduction in their pre-existing visual symptoms and reported visual performance comparable to their fellow asymptomatic eye. Overall, the treatment was considered very satisfactory by patients in terms of visual quality gain. CONCLUSION: Wavefront-guided custom ablation with Alcon's LADARVision4000 was effective in reducing higher order aberrations and related visual symptoms in this preliminary small series. Longer follow-up on more eyes is necessary to assess the accuracy of the algorithm in the correction of defocus, which resulted in a slight overcorrection in this study.

Laser in situ keratomileusis for hyperopia and hyperopic and mixed astigmatism with LADARVision using 7 to 10-mm ablation diameters.

PURPOSE: To evaluate the results of laser in situ keratomileusis (LASIK) performed to correct hyperopia, and hyperopic and mixed astigmatism using wider ablation diameters (optical zone diameter and overall ablation diameter) than those commonly used with the same and other lasers. METHODS: After flap creation using an Alcon SKBM microkeratome set for a 10-mm flap diameter, 53 eyes (33 patients) with a mean spheroequivalent attempted correction of +2.34 +/- 2.09 D underwent LASIK (Alcon LADARVision 4000) using a 7-mm optical zone diameter and a 3-mm transition zone for an overall 10-mm total ablation diameter. The nasal hinge was prevented from undesired ablation by the use of proprietary hinge protector software. Eyes were followed for 6 months after surgery. RESULTS: Six months after surgery, mean spheical equivalent refractive error was -0.22 +/- 0.41 D. There were 79.2% of eyes within +/- 0.50 D, and 98.1% within +/- 1.00 D of intended correction. Uncorrected visual acuity of 20/20 or better was achieved by 28 eyes (53%) and 20/40 or better by 50 eyes (94.3%). No meaningful visual complaints during nighttime hours, such as haloes or glare, were subjectively reported by patients. CONCLUSION: The use of larger ablation diameters in LASIK for hyperopia, and hyperopic and mixed astigmatism produced accurate results, early refractive stability, and good visual performance.

Scraping and mitomycin C to treat haze and regression after photorefractive keratectomy for myopia.

PURPOSE: To evaluate the efficacy, safety, and predictability of therapeutic scraping and application of a diluted 0.02% mitomycin C solution to treat haze and regression after photorefractive keratectomy (PRK) for myopia. METHODS: We performed a non-comparative, non-randomized retrospective study of 35 eyes of 30 patients who had previously undergone PRK for myopia and developed haze and regression after treatment. The range of refractive error after regression was -0.75 to -5.50 D (mean -2.92 D). Haze, ranging from grade 3 to 4 (scale: 0 to 4) caused a best spectacle-corrected visual acuity loss of 1 to 6 Snellen lines. All eyes were treated 6 to 12 months after PRK by scraping the stromal surface and application of a 0.02% mitomycin C solution for 2 minutes using a soaked merocel sponge. No laser ablation was performed. Corneal transparency, refractive error, and visual outcomes were evaluated over a 12-month follow-up period. RESULTS: All eyes had significant improvement in corneal transparency. Thirty-one eyes had haze grades lower than 1, which were maintained over time. Only four eyes showed haze grades 1 to 2 and two of them needed further treatment using the same technique. At 12 months after treatment, all eyes were within +/-1.50 of original intended correction (mean 0.04 +/- 0.63 D). BSCVA improved in all eyes. No toxic effects were observed during re-epithelialization or during follow-up. CONCLUSION: Single application of diluted mitomycin C 0.02% solution following scraping of the corneal surface was effective and safe in treating haze and regression after PRK.

Evaluation of the prophylactic use of mitomycin-C to inhibit haze formation after photorefractive keratectomy.

PURPOSE: To evaluate the results of the prophylactic use of mitomycin-C to inhibit haze formation after excimer laser photorefractive keratectomy (PRK) for medium and high myopia in eyes that were not good candidates for laser in situ keratomileusis (LASIK). SETTING: Carones Ophthalmology Center, Milan, Italy. METHODS: This prospective randomized masked study comprised 60 consecutive eyes (60 patients). The inclusion criteria were a spherical equivalent correction between -6.00 and -10.00 diopters (D) and inadequate corneal thickness to allow a LASIK procedure with a residual stromal thickness of more than 250 microm. The eyes were divided into 2 groups according to the randomization protocol. After PRK, the study group eyes were treated with a single intraoperative dose of mitomycin-C (0.2 mg/mL), applied topically with a soaked microsponge placed over the ablated area and maintained for 2 minutes. The control eyes did not receive this treatment. Refraction, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and slitlamp evidence of corneal opacity (haze) or other visible complications were evaluated. RESULTS: No toxic or side effects were encountered postoperatively. No study group eye had a haze rate higher than 1 during the 6-month follow-up; 19 eyes (63%) in the control group did (P =.01). At 6 months, the between-group difference in the refractive outcome was statistically significant (P =.05), with 26 study group eyes (87%) and 14 control eyes (47%) within +/-0.50 D of the attempted correction. No study group eye had a BCVA loss during the follow-up; 7 control eyes had lost 1 to 3 lines at 6 months (P =.0006). CONCLUSIONS: The prophylactic use of a diluted mitomycin-C 0.02% solution applied intraoperatively in a single dose after PRK produced lower haze rates, better UCVA and BCVA results, and more accurate refractive outcomes than those achieved in the control group.