Laser in situ keratomileusis retreatment for residual myopia and astigmatism

PURPOSE: To evaluate the visual and refractive results of laser in situ keratomileusis (LASIK) retreatment on eyes with residual myopia with or without astigmatism. METHODS: LASIK retreatment was performed on 35 eyes of 23 patients for correction of residual myopia, with or without astigmatism, with a mean manifest spherical equivalent refraction of -2.17+/-0.82 D (range, -1.00 to -3.87 D) and mean refractive astigmatism of -0.55+/-0.61 D (range, 0 to -1.75 D). Retreatment was performed 3 to 18 months after primary LASIK (mean, 5.1+/-2.6 mo). The corneal flap of the previous LASIK was lifted and laser ablation was performed using the Chiron-Technolas Keracor 116 excimer laser. Follow-up was 12 months for all eyes. RESULTS: At 1 year after retreatment, manifest spherical equivalent refraction was reduced to a mean -0.23+/-0.28 D (range, 0 to -0.87 D), and refractive astigmatism was reduced to a mean -0.16+/-0.25 D (range, 0 to -0.75 D). Thirty-two eyes (91.5%) had a manifest spherical equivalent refraction within +/-0.50 D of emmetropia, and 33 eyes (94.3%) had 0 to 0.50 D of refractive astigmatism. Uncorrected visual acuity was 20/20 or better in 11 eyes (31.4%). Spectacle-corrected visual acuity was not reduced in any eye after retreatment. There were no significant complications. CONCLUSION: LASIK retreatment was effective for correction of residual myopia or astigmatism after primary LASIK. Refractive results were predictable with good stability after 3 months. Lifting the flap during LASIK retreatment was relatively easy to perform and did not result in visual morbidity in eyes treated from 3 up to 18 months after primary LASIK.     

Laser in situ keratomileusis for myopia of -1.50 to -6.00 diopters

PURPOSE: To evaluate the results of laser in situ keratomileusis (LASIK) for the correction of low and moderate myopia and astigmatism using the Nidek EC-5000 excimer laser with a modified algorithm. METHODS: Three hundred and ninety-six eyes of 257 patients with myopia ranging from -1.50 to -6.00 D and astigmatism of no more than 4.00 D were included. Manifest spherical equivalent refraction, uncorrected and spectacle-corrected visual acuity were assessed at 1 month (357 eyes, 90%), 3 months (220 eyes, 56%), and 6 months (168 eyes, 42%) after LASIK. RESULTS: Mean preoperative spherical equivalent refraction was -3.60 +/- 1.27 D and mean cylinder was -1.01 +/- 1.08 D. Mean postoperative spherical equivalent refraction was -0.12 +/- 0.31 D and mean cylinder was -0.19 +/- 0.33 D. At 6 months follow-up, 158 eyes (94%) had a mean postoperative spherical equivalent refraction within +/- 0.50 D of emmetropia; 168 eyes (100%) were within +/- 1.00 D. Uncorrected visual acuity was 20/20 or better in 81% (136 eyes) and 20/40 or better in 100%. Two eyes (1.2%) lost 1 line of spectacle-corrected visual acuity due to a decentered ablation. No eye lost 2 or more lines of spectacle-corrected visual acuity. CONCLUSION: Our modified LASIK algorithm with the Nidek EC-5000 excimer laser resulted in safe and predictable outcomes for treatment of low and moderate amounts of myopia and astigmatism.     

Laser in situ keratomileusis for compound myopic astigmatism using the Meditec MEL 70 G-Scan excimer laser

PURPOSE: To determine the safety, efficacy, predictability, and stability of laser in situ keratomileusis (LASIK) in treating patients with myopic astigmatism using the Meditec MEL 70 G-Scan excimer laser. METHODS: Seventy-four eyes of 42 patients with myopia ranging from -4.50 to -9.88 D and astigmatism ranging from 0.50 to 4.00 D who underwent LASIK with the Meditec MEL 70 G-Scan excimer laser and the Summit Krumeich-Barraquer microkeratome were studied. Patients were followed for 1 year. RESULTS: Mean baseline spherical equivalent refraction was -7.12 +/- 1.70 D and cylinder was 1.62 +/- 1.72 D. At 12 months, mean postoperative spherical equivalent refraction was -0.49 +/- 0.57 D and mean refractive cylinder was 0.59 +/- 0.32 D. Mean change in spherical equivalent refraction between 1 and 12 months after surgery was -0.09 +/- 0.31 D, toward myopia. At baseline, no eyes had best spectacle-corrected visual acuity (BSCVA) of 20/20 or better, and 65% had 20/40 or better. At 12 months after surgery, 10% of eyes had BSCVA of 20/20 or better and 88% of eyes had 20/40 or better. The unusually low postoperative BSCVA results were thought to be due to amblyopia or existence of a higher percentage of some optical aberrations in this group of eyes. Mean uncorrected visual acuity was -1.38 +/- 0.42 LogMAR units (20/400) at baseline and -0.29 +/- 0.25 LogMAR units (20/40) at the 12-month postoperative examination. No eyes lost two or more lines of spectacle-corrected visual acuity. No vision threatening complications were observed. CONCLUSIONS: LASIK with the Meditec MEL 70 G-Scan excimer laser appeared to be safe, effective, reasonably predictable, and stable for correction of myopic astigmatism with a spherical component between -4.25 and -8.25 D and a cylindrical component between 0.50 and 4.00 D. However, astigmatism was slightly undercorrected with the algorithm used.     

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.     

Toric laser in situ keratomileusis for myopic astigmatism using an ablatable mask

BACKGROUND: To assess the results of toric laser in situ keratomileusis (LASIK) correction of myopic astigmatism. METHODS: A prospective study was performed over a 20 week period for consecutive patients treated for myopic astigmatism. Spectacle-corrected visual acuity, uncorrected visual acuity, spectacle refraction, videokeratography, and complications were recorded. Vector analysis was performed by the ASSORT program. RESULTS: Sixty-five eyes of 42 patients underwent toric LASIK with a Summit Technologies Apex Plus excimer laser. Mean preoperative spherical equivalent refraction at the spectacle plane was -6.24 +/- 2.42 D (range, -1.63 to -14.63 D) and mean pre-operative refractive cylinder magnitude was 1.99 +/- 1.35 D (range, 0.75 to 7.00 D); mean attempted refractive cylinder correction was 1.90 +/- 1.00 D. Six months after LASIK (43 eyes followed), mean spherical equivalent refraction at the spectacle plane was -0.40 +/- 0.55 D and 31 eyes (72.1%) were within +/- 0.50 D of emmetropia. At 6 months, mean refractive cylinder magnitude was 0.74 +/- 0.70 D, mean surgically induced astigmatism was 1.46 +/- 0.86 D, mean absolute angle of error was 10.33 degrees, mean astigmatic correction index was 0.93 +/- 0.36 D, and mean index of success was 0.46 +/- 0.39. Uncorrected visual acuity was 6/12 or better in 34 eyes (79.1%) and 6/6 in 15 eyes (35%); spectacle- corrected visual acuity was 6/9 or better in 41 eyes (95.35%). Six eyes (14.0%) lost 1 line of spectacle-corrected visual acuity at 6 months and one eye (2.3%) lost 2 lines. Ten eyes (23.3%) gained 1 line at 6 months. CONCLUSION: Toric LASIK with an ablatable mask using the Summit Apex Plus excimer laser is a safe and relatively accurate procedure for the correction of myopic astigmatism.     

Laser in situ keratomileusis for correction of high astigmatism after penetrating keratoplasty

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) for correction of high astigmatism after penetrating keratoplasty, and to assess the refractive results and predictability of the procedure. METHODS: LASIK was performed on 19 patients (19 eyes) with high astigmatism after penetrating keratoplasty, using the Chiron Automated Corneal Shaper and the Chiron-Technolas Keracor 116 excimer laser. The amount of preoperative refractive astigmatism ranged from 6.50 to 14.50 D (mean, 9.21 +/- 1.95 D) and the spherical component of manifest refraction ranged from -7.00 to +1.25 D (mean, -2.14 +/- 2.11 D). All patients completed a minimum follow-up of 12 months. RESULTS: Refraction was stable after 3 months. At 1 year after LASIK, the amount of refractive astigmatism was reduced to a mean of 1.09 +/- 0.33 D (range, 0.50 to 1.75 D), with 57.9% of the eyes within +/- 1.00 D of refractive astigmatism. The mean percent reduction of astigmatism was 87.9 +/- 3.7%. The postoperative spherical component of manifest refraction ranged from -1.00 to +1.75 D with a mean of +0.43 +/- 0.82 D. Vector analysis showed that the mean amount of axis deviation was 1.1 +/- 1.3 degrees and the mean percent correction of preoperative astigmatism was 92.6 +/- 8.4%. There were no intraoperative complications. Spectacle-corrected visual acuity was not reduced in any eye, and improved by 2 or more lines in 42.1% of eyes after LASIK. CONCLUSION: LASIK with the Chiron-Technolas Keracor 116 excimer laser was effective for correction of both astigmatism and myopia after penetrating keratoplasty. The procedure proved to be safe and gave fairly predictable and stable refractive results.     

Laser in situ keratomileusis for myopia and hyperopia using the Lasersight 200 laser in 300 consecutive eyes

PURPOSE: To evaluate effectiveness, safety, predictability, and short-term stability of laser in situ keratomileusis (LASIK) using the LaserSight Compac-200 Mini excimer laser with software version 9.0, for all refractive errors. METHODS: One hundred fifty consecutive patients (300 eyes) that received bilateral LASIK for myopia, hyperopia, and astigmatism were studied prospectively. A new 9.0 software version applying a modified nomogram that takes advantage of bilateral surgery was used. Follow-up at 6 months was available for 267 eyes (89%). RESULTS: Six months postoperatively, 131 eyes (96.32%) in the low to moderate myopia group (-1.00 to -5.99 D; n=136) had a spherical equivalent refraction within +/-1.00 D, and 123 eyes (90.44%) were within +/-0.50 D of emmetropia. In the high to extreme myopia group (-6.00 to -25.00 D; n=114), 97 eyes (87.08%) had a spherical equivalent refraction within +/-1.00 D and 78 eyes (68.42%) were within +/-0.50 D of emmetropia. In the hyperopia group (+1.00 to +6.00 D; n=50), 44 eyes (88%) had a postoperative spherical equivalent refraction within +/-1.00 D, and 31 eyes (62%) were within +/-0.50 D of emmetropia. Mean change in spherical equivalent refraction at 6 months was less than -0.50 D in the low to high myopia groups and -1.16 +/- 0.55 D in the extreme myopia group. At 6 months follow-up, uncorrected visual acuity was 20/20 or better in 73 eyes (54%) in the low to moderate myopia groups and 21 eyes (18%) in the high to extreme myopia groups. In the hyperopia group at 6 months follow-up, uncorrected visual acuity was 20/20 or better in 31 eyes (62%) and 20/40 or better in 41 eyes (82%). Only two eyes had a temporary loss of two or more lines of spectacle-corrected visual acuity due to corneal folds that were surgically treated. Six months after LASIK, no eye had lost any lines of best spectacle-corrected visual acuity in this series. CONCLUSIONS: Our modified LASIK nomogram with the 9.0 software of the LaserSight 200 excimer laser (with a larger and smoother ablation pattern) resulted in safe and effective outcomes for the treatment of low to high myopia, astigmatism, and hyperopia.     

Laser in situ keratomileusis for the correction of residual ametropia after penetrating keratoplasty

PURPOSE: To evaluate the safety, efficacy, and predictability of excimer laser in situ keratomileusis (LASIK) to correct residual myopia and astigmatism after penetrating keratoplasty (PKP). SETTING: Buzard Eye Institute, Las Vegas, Nevada, USA. METHODS: Twenty-six eyes had LASIK at least 1 year after PKP. All eyes were followed for at least 6 months after LASIK; 22 eyes were followed for 12 months. Sutures were removed at a mean of 13 months post PKP. Laser in situ keratomileusis was performed with the Chiron Automated Corneal Shaper microkeratome (Bausch & Lomb) and the Visx Star excimer laser. Before LASIK, the mean spherical equivalent (SE) was -4.94 diopters (D) +/- 2.79 (SD) and the mean astigmatism was 2.71 +/- 2.33 D; all eyes had regular astigmatism or slightly decentered, irregular astigmatism. RESULTS: At the last follow-up, the mean postoperative uncorrected visual acuity (UCVA) was 20/30, the mean SE was -0.35 +/- 0.65 D, and the mean residual astigmatism was 1.06 +/- 0.67 D. Eighty-six percent of patients had an SE within +/-1.00 D of emmetropia and a UCVA of 20/40 or better. Ten eyes (39%) had 1 or more enhancements, which were performed a mean of 6 months after the primary LASIK. Significant complications such as wound dehiscence, epithelial ingrowth, and corneal decompensation did not occur. At the last follow-up, 18% of patients lost 1 line of best corrected visual acuity and 27% gained 1 line. CONCLUSION: Laser in situ keratomileusis appeared to be a reliable and safe procedure to correct residual myopia and astigmatism after PKP.     

Laser in situ keratomileusis for the correction of hyperopia from +1.25 to +5.00 diopters with the Technolas Keracor 117C laser

PURPOSE: To assess the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) in patients with hyperopia and to evaluate the visual and refractive results of the procedure. METHODS: LASIK was performed on 85 eyes of 53 patients for correction of hyperopia, with a preoperative mean manifest spherical equivalent refraction of +3.31 +/- 0.69 D (range, +1.25 to +5.00 D) and mean refractive astigmatism of +0.91 +/- 1.06 D (range, 0 to +3.00 D). The Carriazo-Barraquer (Moria) manual microkeratome was used to create the corneal flap, and laser ablation was performed using the Technolas Keracor 117C excimer laser with an ablation zone diameter of 6.0 mm and a transition zone diameter to 9.0 mm. Follow-up was 12 months for all patients. RESULTS: Refraction was stable by 3 months after surgery. At 1 year after LASIK, the mean manifest spherical equivalent refraction was +0.43 +/- 0.57 D (range, -1.25 to +2.00 D) and refractive astigmatism was reduced to a mean of 0.36 +/- 0.30 D (range, 0 to 1.00 D). Fifty-two eyes (61.2%) had a manifest spherical equivalent refraction within +/- 0.50 D of emmetropia, and 76 eyes (89.4%) were within +/- 1.00 D. Uncorrected visual acuity was 20/20 in 21 eyes (24.7%) and 20/40 or better in 79 eyes (92.9%). Spectacle-corrected visual acuity was reduced by two lines in one eye (1.2%) and improved by two lines in five eyes (5.9%). There were no significant complications. CONCLUSION: LASIK was an effective, safe, and predictable procedure for the correction of hyperopia up to +5.00 D and hyperopic astigmatism up to +3.00 D with the Technolas Keracor 117C excimer laser. The large size of the corneal flap obtained by the Carriazo-Barraquer (Moria) manual microkeratome facilitated laser ablation entirely in the exposed corneal stromal bed.     

Two-stage laser in situ keratomileusis to correct refractive errors after penetrating keratoplasty

PURPOSE: To evaluate the effect of a two-stage laser in situ keratomileusis (LASIK) procedure on eyes with high astigmatism and/or anisometropia after penetrating keratoplasty. METHODS: Eleven postoperative penetrating keratoplasty eyes were included in a prospective, non-controlled study. All patients had at least 4.00 D of astigmatism and/or at least 3.00 D of anisometropia and were spectacle and contact lens intolerant. Two-stage LASIK was performed; in the first stage a hinged corneal flap 160 microm in thickness and 9 mm in diameter was created. After stabilization of corneal shape (1 to 3 months after keratotomy), the corneal flap was lifted and laser refractive treatment (second stage) was performed. RESULTS: After the first stage, a statistically significant reduction in refractive astigmatism (P<.01) was recorded. In all eyes but one, best spectacle-corrected visual acuity was maintained or improved after the procedure. Three months after the second stage, refractive astigmatism in 8 of 11 eyes (73%) was within +/- 1.00 D, and spherical equivalent refraction in 9 of 11 eyes (82%) was within +/- 1.00 D of intended correction. Preoperative irregular astigmatism persisted in three patients (3 eyes) who could not be corrected within +/- 1.00 D of refractive astigmatism and/or +/- 1.00 D of intended spherical equivalent refraction. In one eye, an interface infiltrate developed shortly after creation of the flap, and resulted in limited melting. CONCLUSIONS: A two-stage LASIK procedure improved visual acuity and refraction in postoperative penetrating keratoplasty eyes with high astigmatism and/or anisometropia. Complications were uncommon but can lead to loss of vision.     

Laser in situ keratomileusis for correction of induced astigmatism from cataract surgery

PURPOSE: To evaluate the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) to correct residual astigmatism after cataract surgery. METHODS: LASIK was performed on 20 eyes of 20 patients with refractive myopic or mixed astigmatism (3.00 to 6.00 D) at least 1 year after extracapsular cataract extraction with posterior chamber intraocular lens implantation without complication. Each eye received bitoric LASIK with the Nidek EC-5000 excimer laser and the Automated Corneal Shaper microkeratome. RESULTS: At 6 months after LASIK, mean refractive cylinder decreased from 4.64+/-0.63 D to 0.44+/-0.24 D (P<.001). Mean percent reduction of astigmatism was 90.4+/-5.0% (range 80% to 100%). Mean spherical equivalent refraction decreased from -2.19+/-0.88 D (range -1.00 to -3.88 D) to -0.32+/-0.34 D (range -1.25 to +0.38 D) (P<.001). Vector analysis showed that the mean amount of axis deviation was 0.7+/-1.2 degrees (range 0 degrees to 4.3 degrees) and the mean percent correction of preoperative astigmatism was 92.1+/-5.9% (range 85.6% to 108%). Eighty-five percent of all eyes had a mean spherical equivalent refraction and mean cylinder within +/-0.50 D of emmetropia. Change in spherical equivalent refraction and cylinder from 2 weeks to 6 months was < or = 0.50 D in 90% (18 eyes) and 95% (19 eyes), respectively. Spectacle-corrected visual acuity was not reduced in any eye. Diffuse lamellar keratitis occurred in three eyes (15%) after LASIK, and were treated successfully with eyedrops. CONCLUSION: LASIK was an effective, predictable, stable, and safe procedure for correction of residual myopic or mixed astigmatism ranging from 3.00 to 6.00 D with a low spherical component after cataract surgery.     

Astigmatic keratotomy for post-keratoplasty astigmatism

PURPOSE: To assess astigmatic keratotomy as a means of managing post-keratoplasty astigmatism in the era of excimer laser refractive surgery. SETTING: Moorfields Eye Hospital, London, England. METHODS: Fifty paired arcuate keratotomies were performed with refractive and topographic guidance. Refraction, uncorrected visual acuity, best corrected visual acuity, and visual acuity with the patient's preferred correction were measured before and after surgery. RESULTS: The median follow-up was 34 months. The mean cylinder was 9.13 diopters (D) preoperatively and 4.85 D postoperatively. The mean spherical equivalent refraction was -4.21 D preoperatively and -4.26 D postoperatively. The amount of cylinder reduction was correlated with the amount of pre-existing cylinder (P<.001). Thirty eyes (60%) gained and 1 eye (2%) lost Snellen acuity with preferred correction. In the remaining 19 eyes (38%), there was no change in acuity with preferred correction. The mean change in visual acuity with preferred correction was a gain of 1.5 Snellen lines. Three patients intolerant of spectacles or contact lenses before surgery became tolerant. Ten patients (20%) previously unsuitable for laser in situ keratomileusis (LASIK) because of high cylindrical error went on to have LASIK. CONCLUSIONS: Astigmatic keratotomy remains a useful, safe, relatively simple surgical procedure for treating post-keratoplasty astigmatism. Reduction in cylinder was correlated with pre-existing cylinder. Vision with preferred correction was improved in 60% of cases. High astigmatism reduced to a level at which more definitive refractive surgery such as LASIK became feasible.     

Laser in situ keratomileusis to correct refractive errors after keratoplasty

PURPOSE: To assess the safety and effectiveness of excimer laser in situ keratomileusis (LASIK) to correct refractive myopia, astigmatism, or both after keratoplasty. SETTING: Eye Clinic Day Hospital, S?o Paulo, Brazil. METHODS: Twenty-two eyes that had previously had corneal transplantation were studied. Laser in situ keratomileusis was performed using the Chiron automated microkeratome and the VISX Twenty-Twenty B excimer laser. RESULTS: Mean follow-up after LASIK was 10.09 months +/- 3.87 (SD). The spherical equivalent refraction dropped from -4.55 +/- 3.66 D before LASIK to -0.67 +/- 1.24 D after surgery. At the last examination, 72.7% of patients had a refractive error within +/- 1.00 D of emmetropia and 54.5% had uncorrected visual acuity of 20/40 or better. Vector analysis of astigmatic correction showed an index of success of 54.0%. Best spectacle-corrected visual acuity was unchanged in 8 cases, improved in 9, and decreased in 5. Significant endothelial cell loss, keratoplasty wound dehiscence, and other serious complications did not develop in any eye. CONCLUSION: The correction of refractive error with LASIK in postkeratoplasty patients proved to be safe, effective, and predictable. Further studies with longer follow-up are needed to determine the method's clinical value.     

Photorefractive keratectomy or laser in situ keratomileusis for residual refractive error after phakic intraocular lens implantation

PURPOSE: To evaluate the results of combining phakic posterior chamber intraocular lens (IOL) implantation and excimer corneal surgery to treat high myopia or myopia with astigmatism. SETTING: Service d'Ophtalmologie, H?pital Purpan, University of Toulouse, Toulouse, France. METHODS: Thirty-two eyes of 28 patients with extreme myopia or myopia combined with astigmatism were treated by implantation of a phakic posterior chamber IOL. Residual refractive errors were treated no earlier than 6 weeks after IOL implantation by photorefractive keratectomy (PRK) in eyes with low refractive errors or by laser in situ keratomileusis (LASIK) in eyes with higher residual refractive errors. RESULTS: The mean preoperative spherical equivalent (SE) refraction was -18.7 diopters (D). The refractive astigmatism ranged from 0 to 3.5 D. After excimer laser treatment, the SE refraction ranged from -0.5 to -2.5 D and the refractive astigmatism, from 0 to 1.5 D in the PRK group. In the LASIK group, spherical ametropia ranged from -1.5 to +1.5 D and astigmatism, from 0 to 1.0 D. After excimer laser treatment, the uncorrected visual acuity improved in all eyes but a loss of 1 line of the corrected vision after IOL implantation occurred in 22.2% of PRK-treated eyes and in 13.6% of LASIK-treated eyes. CONCLUSIONS: Bioptic treatment of extreme myopia and myopia associated with astigmatism appears to be safer and more predictable than other methods of treatment.     

Laser in situ keratomileusis in children 8 to 15 years old

PURPOSE: To determine the safety, efficacy, predictability, and stability of laser in situ keratomileusis (LASIK) to correct high myopia or high myopic astigmatism in patients with high anisometropia in whom conventional treatments have failed. METHODS: Nine eyes of nine patients, three boys and six girls with high anisometropia (>3.50 D), were included in this study. Patient age was 8 to 15 years. Minimum follow-up was 12 months. All patients were treated with the Chiron Technolas 217 excimer laser. RESULTS: Three months after LASIK, uncorrected visual acuity improved by at least five Snellen lines in all eyes. Three eyes (33.3%) were 20/40 or better without correction. Due to dense amblyopia, no eye had uncorrected visual acuity of 20/20 or better. The mean spherical equivalent refraction decreased from -7.66 to -0.22 D, and mean preoperative astigmatism decreased from -3.11 to -0.69 D. Eight eyes (88.8%) were within +/-1.00 D of emmetropia. Two eyes (22.2%) were within +/-0.50 D of the desired outcome. All patients were able to function binocularly. CONCLUSION: In this study of selected older children, LASIK was a safe and effective option for the correction of high anisometropia and for improved binocularity, when conventional therapies had failed. Further study is necessary to determine the long-term refractive stability in these young patients.     

Laser in situ keratomileusis for residual myopia after primary LASIK

PURPOSE: To analyze the results of secondary laser in situ keratomileusis (LASIK) for residual myopia after primary LASIK. SETTING: Dr. Agarwal's Eye Hospital, Chennai, India. METHODS: A retrospective study of 50 eyes of 29 patients who had a secondary LASIK procedure was carried out. After a mean follow-up of 5.84 months +/- 3.24 (SD) after the primary procedure, the mean myopic residual refraction was -4.30 +/- 1.83 diopters (D). In 10 eyes, the primary corneal flap was lifted by blunt dissection. In 40 eyes, the flap was made with a second cut. The secondary LASIK was performed using the Chiron Technolas Keracor 217 excimer laser and the Automated Corneal Shaper microkeratome (Bausch & Lomb). RESULTS: The mean follow-up was 16.58 +/- 3.06 months. At 12 months, the mean spherical equivalent was -0.45 +/- 0.68 D (P <.05). Thirty-one eyes were emmetropic, 13 eyes were within +/-1.00 D of emmetropia, and 5 eyes were within +/-2.00 D. The mean uncorrected visual acuity improved from 20/80 (range 20/60 to 20/200) to 20/40 (range 20/20 to 20/200) (P <.005). Seventeen eyes gained 1 line of best spectacle-corrected visual acuity; 1 eye lost 1 line because of a decentered ablation with an induced postoperative astigmatism of -3.50 D cylinder. No sight-threatening complications such as a free cap, flap irregularity, corneal ectasia, or retinal complication occurred postoperatively. Epithelial ingrowth developed in 5 eyes and corneal thinning, in 1 eye. Three eyes had night glare. CONCLUSION: Secondary LASIK was a safe, stable, and effective method for the treatment of residual myopia after primary LASIK.     

Proper positioning of the plume evacuator in the VISX Star3 excimer laser minimizes central island formation in patients undergoing laser in situ keratomileusis

PURPOSE: To identify risk factors in a series of patients who developed steep central islands after laser in situ keratomileusis (LASIK). METHODS: We analyzed and compared the refractive and topographic outcome of a study group composed of 83 eyes of 44 patients who underwent LASIK using the VISX Star3 excimer laser with a refraction-matched control group of 83 eyes treated later. The vacuum aspirator of the excimer laser was abnormally positioned during the surgeries performed in the study group. RESULTS: Mean preoperative spherical equivalent refraction in the study group was -6.75 +/- 2.50 D. Four eyes with a mean preoperative spherical equivalent refraction of -9.27 +/- 2.29 D developed steep central islands. Thirty-three (38%) of 83 eyes treated needed retreatment for residual myopia or myopic astigmatism. In the control group, mean preoperative spherical equivalent refraction was -6.76 +/- 2.50 D. Ninety-three percent of eyes were within +/- 1.00 D of target refraction. Five (6.02%) of 83 eyes required retreatment and no eyes developed central islands. CONCLUSION: The abnormally positioned vacuum aspirator coupled with the higher preoperative refractive correction were the likely causative factors for central island formation and the increased incidence of undercorrection in these patients.     

Laser in situ keratomileusis to correct residual myopia after cataract surgery

PURPOSE: To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) for correcting residual myopia after cataract surgery with intraocular lens implantation. METHODS: Twenty-two eyes of 22 patients underwent LASIK for the correction of residual myopia after cataract surgery. LASIK was carried out using the Chiron Automated Corneal Shaper and the NIDEK EC-5000 excimer laser. In all eyes, the follow-up was 12 months. RESULTS: Before LASIK, 1 eye (4.5%) had an uncorrected visual acuity of 0.5 or better; 12 months after LASIK, 10 eyes (45.4%) achieved this level of visual acuity and 0 eyes achieved 1.00 or better. Before LASIK, mean refraction was -2.90 +/- 1.80 D; 12 months after LASIK it decreased significantly to 0.40 +/- 0.60 D (P < .01). In 18 eyes (81.8%) at 12 months after LASIK, spherical equivalent refraction was within +/-1.00 D of emmetropia; 11 eyes (50%) were within 0.50 D. No vision-threatening complications occurred. CONCLUSION: LASIK with the Automated Corneal Shaper and Nidek EC-5000 excimer laser was an effective, predictable, stable, and safe procedure for correcting residual myopia after cataract surgery. No intraocular lens or cataract incision related complications occurred when LASIK was performed at least 3 months after phacoemulsification.     

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.     

Laser in situ keratomileusis for the correction of myopia and myopic astigmatism

PURPOSE: To evaluate the efficacy, safety, predictability, and surgically induced astigmatism (SIA) of laser in situ keratomileusis (LASIK) for the correction of myopia and myopic astigmatism. SETTING: Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan. METHODS: This retrospective study comprised 69 eyes that had LASIK to correct myopia and 74 eyes that had LASIK to correct myopic astigmatism. The excimer laser keratectomy was performed using a Summit Apex Plus machine. Refraction, visual acuity, and computerized corneal videokeratography data from the preoperative and postoperative examinations were collected. The astigmatic change was calculated by the Alpins vector analysis method. RESULTS: The preoperative spherical equivalent at the glasses plane in the myopia and myopic astigmatism groups was -8.08 diopters (D) and -9.73 D, respectively. At 6 months, the spherical equivalent and residual corneal astigmatism were -0.25 D and 0.85 D, respectively, in the myopia group and -0.71 D and 0.82 D, respectively, in the myopic astigmatism group. In the myopia group, 88% of eyes were within +/-1.0 D of the intended myopia correction and in the myopic astigmatism group, 85% were within +/-1.0 D of the targeted spherical equivalent and 90% were within +/-1.0 D of the intended astigmatism correction. The uncorrected visual acuity was 20/40 or better in 94.1% of eyes in the myopia group and 92.5% of eyes in the myopic astigmatism group. The SIA magnitude was 0.66 D with the axis randomly distributed in the myopia group. The mean astigmatism correction index was 0.97, the mean magnitude of error was 0.13 D +/- 0.62 (SD), and the mean angle of error was -3.70 +/- 13.73 degrees in the myopic astigmatism group. CONCLUSION: Laser in situ keratomileusis had similar predictability, safety, and efficacy in the treatment of myopia and myopic astigmatism. The astigmatism correction was effective, but the results suggest that subjective astigmatism of less than 1.0 D need not be treated with the Summit Apex Plus laser.