Laser in situ keratomileusis for hyperopia and hyperopic astigmatism with the Nidek EC-5000 Excimer laser.

PURPOSE: We evaluated the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) for hyperopia and hyperopic astigmatism. METHODS: A retrospective study was performed for 92 eyes of 62 consecutive patients to evaluate uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA) and manifest refraction before and 3 and 6 months after LASIK (Moria LSK-ONE microkeratome, Nidek EC-5000 excimer laser). Eyes were divided into groups: Group 1 (low hyperopia) for spherical correction of +1.00 to +3.00 D (22 eyes), Group 2 (low hyperopic astigmatism) for toric correction with spherical equivalent refraction of +1.00 to +3.00 D (18 eyes), Group 3 (moderate hyperopia) for spherical correction of +3.25 to +6.00 D (10 eyes), and Group 4 (moderate hyperopic astigmatism) for toric correction with spherical equivalent refraction between +3.25 and +6.00 D (18 eyes). RESULTS: At 3 and 6 months after LASIK, 68 eyes (73.9%) were available for follow-up examination. Percentage of eyes with a spherical equivalent refraction within +/-0.50 D of emmetropia for Group 1 was 54.5% (12 eyes); Group 2, 50% (9 eyes); Group 3, 40% (4 eyes), and Group 4, 38.8% (7 eyes). UCVA > or =20/20 in Group 1 was 14% and in Groups 2, 3, and 4, 0%. One eye (5.5%) lost two lines of BSCVA. CONCLUSION: LASIK with the Moria LSK-ONE microkeratome and the Nidek EC-5000 excimer laser reduced low and moderate hyperopia and was within +/-0.50 D of target outcome in approximately 50% of eyes. Undercorrection was evident in all groups. The procedure was safe.     

Laser in situ keratomileusis for the correction of hyperopia from +0.50 to +11.50 diopters with the Keracor 117C laser

PURPOSE: To evaluate excimer laser in situ keratomileusis (LASIK) for the correction of hyperopia. METHODS: We reviewed retrospectively the medical records of 46 patients treated with LASIK for hyperopia. All patients had a complete ophthalmologic evaluation. The corneal bed was ablated using the Bausch & Lomb Chiron Keracor 117C excimer laser to create a paracentral annular ablation under a nasally hinged 160-microm corneal flap with the Chiron Automatic Corneal Shaper microkeratome. Follow-up was a minimum of 6 months. RESULTS: Eighty eyes of 46 patients (23 males and 23 females) were included. Age ranged from 18 to 65 years (mean, 42 yr). The range of preoperative spherical equivalent refraction was +0.50 to +11.50 D (mean, +3.40 D). Mean postoperative spherical equivalent refraction at 6 months was +0.26 D. Six months after surgery, 35 eyes (44%) achieved uncorrected visual acuity of 20/20 or better and 78 eyes (97.5%) achieved 20/40 or better. Forty-six eyes (58%) had a postoperative spherical equivalent refraction within +/-0.50 D of attempted correction, and 67 eyes (84%) were within +/-1.00 D of attempted correction. When using the Bausch & Lomb Chiron Keracor 117C excimer laser to correct hyperopia, eyes with a spherical equivalent refraction less +2.00 D should be overcorrected by 25%, +2.00 to +4.00 D by 30%, and over +4.00 by 40%. The positive cylinder should be overcorrected by 10%. CONCLUSIONS: LASIK was safe and effective in the treatment of hyperopia from +0.50 to +11.50 D. Regression following LASIK for hyperopia remains a problem. A special nomogram was required to achieve results comparable with those for myopia.     

Laser in situ keratomileusus for mixed and simple myopic astigmatism with the Nidek EC-5000 Laser

PURPOSE: To evaluate the visual and refractive results of laser in situ keratomileusis (LASIK) for mixed and simple myopic astigmatism using bitoric ablation. METHODS: A retrospective study was performed in 65 eyes of 38 consecutive patients to evaluate uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA) and cyclopegic and manifest refraction, before and 3 and 6 months after LASIK (Moria LSK-ONE microkeratome, Nidek EC-5000 excimer laser). RESULTS: At 3 and 6 months after LASIK, 40 eyes of 24 patients (64.5%) were available for follow-up examination. Mean age was 25.9 +/- 6.6 years (range 18 to 43 yr). Mean preoperative manifest spherical equivalent refraction was -1.40 +/- 0.80 D (range -3.80 to +0.50 D) mean preoperative cylinder was -3.30 +/- 1.30 D (range -1.00 to -6.00 D). At 6 months follow-up, mean manifest spherical equivalent refraction was +0.30 +/- 0.46 D (range -0.38 to +1.88 D), mean cylinder was -0.73 +/- 0.61 D (range -2.25 to 0 D). There was a 77.8% decrease in astigmatism magnitude. According to vector analysis, mean achieved vector magnitude was 80% of intended. Fifty percent (20 eyes) had a cylinder within +/- 0.50 D of emmetropia. Twenty-three eyes (57.5%) had a spherical component within +/- 0.50 D. Eighty-five percent (34 eyes) had postoperative UCVA of 20/40 or better. Ten percent (four eyes) lost two lines of Snellen BSCVA, whereas 35% (14 eyes) gained one or more lines. CONCLUSIONS: Bitoric LASIK with the Moria LSK-ONE microkeratome and Nidek EC-5000 excimer laser was effective and safe for the reduction of cylinder in mixed and simple myopic astigmatism. Moderate undercorrection of the cylinder was evident.     

Five-year follow-up of laser in situ keratomileusis for hyperopia using the Technolas Keracor 117C excimer laser

PURPOSE: To evaluate safety, predictability, efficiency, and long-term stability of laser in situ keratomileusis (LASIK) for spherical hyperopia. METHODS: This study was a retrospective 5-year analysis of 67 patients (125 eyes) who had LASIK for spherical hyperopia; preoperative mean manifest spherical equivalent refraction was +3.84+/-1.13 D (range +1.00 to +6.50 D) and mean astigmatism was 0.37+/-0.27 D (range 0 to 1.00 D). Preoperative spherical equivalent refraction for the low hyperopia group was +1.00 to +2.75 D; medium hyperopia group, +3.00 to +4.25 D, and high hyperopia group, +4.50 to +6.50 D. All surgeries were performed using the scanning Chiron Technolas Keracor 117C excimer laser. Uncorrected and best spectacle-corrected visual acuity, predictability, long-term stability of refraction, and complications were analyzed. RESULTS: At 5 years after hyperopic LASIK, mean spherical equivalent refraction for the low hyperopia group was +0.48D+/-0.79 D; medium hyperopia group, +1.52+/-1.45 D; high hyperopia group C, +3.39+/-1.98 D. The percentage of eyes with a spherical equivalent refraction within +/-0.50 D of emmetropia for the low hyperopia group was 63% (37 eyes); medium hyperopia group, 42% (20 eyes); high hyperopia group, 22% (4 eyes). Eyes with chronic dry eye symptoms had a mean difference in spherical equivalent refraction from target refraction of +1.43 D compared with +0.84 D for eyes without dry eye symptoms. Five eyes (4%) lost 2 lines of BSCVA at 5 years. CONCLUSION: LASIK was safe, effective, and stable for primary hyperopia between +1.00 and +3.00 D. Higher amounts of hyperopia had poor long-term stability, especially eyes with more than +4.25 D. Chronic dry eye symptoms were associated with regression over time.     

Two-year follow-up of laser in situ keratomileusis for hyperopia

PURPOSE: To evaluate excimer laser in situ keratomileusis (LASIK) for hyperopia and its predictability. METHODS: We performed a retrospective study of 100 eyes that had LASIK for hyperopia to assess predictability and long-term stability of refractive results. The Chiron Automated Corneal Shaper was used to create the flap and the Keracor 117CT Chiron-Technolas excimer laser with the plano-scan program was used to ablate all corneas. RESULTS: Mean baseline spherical equivalent manifest refraction was +4.50 +/- 1.73 D (range, +1.25 to +8.50 D). Six months after LASIK, mean manifest spherical equivalent refraction was +0.72 +/- 1.87 D (range, -1.75 to +2.50 D), at 1 year, +0.88 +/- 1.73 D (range, -1.25 to +2.50 D), and at 2 years, +0.85 +/- 1.74 D (range, -0.50 to +2.75 D). Two years after LASIK, 45 eyes (74%) were within +/-1.00 D of intended correction and within +/-1.00 D of emmetropia. Uncorrected visual acuity was 20/40 or better in 50 eyes (82%) at 2 years; 29 eyes (37%) saw 20/20 or better. Undercorrection occurred more frequently in eyes with preoperative keratometric power of more than 45.00 D, when ablation zones less than 6 mm were used and when higher amounts of hyperopic correction were required. CONCLUSION: LASIK with the Keracor 117CT excimer laser appears to be an effective and safe procedure to correct hyperopia. Preoperative keratometric power, amount of hyperopia, and ablation zone diameter affect the efficacy and long-term stability of the procedure.     

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 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 recurrent hyperopia following laser thermal keratoplasty

PURPOSE: Laser thermal keratoplasty (LTK) has its main indication in the correction of hyperopia. However, regression of refractive effect following LTK is a limitation. Laser in situ keratomileusis (LASIK) may provide a good alternative to correct residual refractive errors. METHODS: Fifty hyperopic eyes with varying amounts of regression after LTK underwent LASIK. The Chiron Automated Corneal Shaper microkeratome was used to make a flap of 160 microm and laser ablation was performed with the Technolas 217 Planoscan excimer laser. Postoperative follow-up was 6 months. RESULTS: Mean spherical equivalent refraction improved from +2.92+/-1.60 D to +0.36+/-1.48 D. Mean best spectacle-corrected visual acuity changed from 0.78+/-0.14 before LASIK to 0.76+/-0.16 D 6 months after LASIK. Mean uncorrected visual acuity changed from 0.37+/-0.16 to 0.66+/-0.24. Forty-two percent (21 eyes) were within +/-0.50 D of intended correction, 60% (30 eyes) were within +/-1.00 D, and 76% (38 eyes) were within +/-2.00 D. After LASIK, confluent haze between previous LTK spots was observed in most eyes, as LASIK ablation took place at the sites of the LTK spots. CONCLUSIONS: LASIK after LTK is a good alternative for hyperopic regression. Predictability and efficacy are less than with primary LASIK for hyperopia, but the procedure is equally safe.     

Laser in situ keratomileusis for correction of hyperopia and hyperopic astigmatism with the Technolas 117C

PURPOSE: To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) for correction of hyperopia and hyperopic astigmatism. METHODS: Fifty-four hyperopic eyes of 35 patients with a spherical equivalent refraction between +1.00 and +6.00 D were followed for at least 12 months following LASIK. All surgery was performed with the scanning Chiron Technolas Keracor 117C excimer laser. Data on uncorrected and spectacle-corrected visual acuity, predictability, stability of refraction, and complications were analyzed. RESULTS: At 12 months, the average residual refraction was +0.29 +/- 0.78 D; 83.3% of eyes (45 eyes) were in the range of +/- 1.00 D and 61.1% of eyes (33 eyes) were within +/- 0.50 D of emmetropia. Fifty eyes (92.6%) had uncorrected visual acuity of 20/40 or better and 34 (63.0%) eyes had 20/20 or better. One eye (1.9%) lost two lines of best spectacle-corrected visual acuity and two eyes (3.7%) gained two or more lines. Two patients (two eyes, 3.7%) had complaints of halos and one patient (one eye, 1.9%) had glare at 12 months after LASIK for hyperopia. CONCLUSIONS: LASIK was used to treat hyperopia from +1.00 to +6.00 D with good predictability and safety. Primary and second hyperopia require different nomograms, according to our experience.     

Laser in situ keratomileusis for myopic astigmatism

PURPOSE: To evaluate the refractive results of laser in situ keratomileusis (LASIK) for myopic astigmatic eyes, and to assess the efficacy, accuracy, stability, and safety of the procedure. METHODS: LASIK was performed on 113 eyes of 73 patients for correction of myopic astigmatism ranging from 1.00 to 5.00 D, as measured by manifest refraction, with a mean baseline refractive astigmatism of 2.09 +/- 1.12 D. The Chiron Automated Corneal Shaper was used to create a corneal flap, and laser ablation was performed using the Chiron-Technolas Keracor 116 excimer laser. Follow-up time was 12 months for all eyes. RESULTS: Refractive astigmatism was stable by 3 months after surgery. At 1 year after LASIK, refractive astigmatism was reduced to a mean of 0.25 +/- 0.31 D (range 0 to 1.00 D). Sixty-one eyes (54%) had no residual astigmatism and 98 eyes (86.7%) had 0 to 0.50 D of refractive astigmatism. The mean percent reduction of preoperative astigmatism was 87.9 +/- 14.9%. The mean axis deviation of the surgically induced astigmatism was 2.1 +/- 3.1 degrees, with 96 eyes (84.9%) within 5 degrees of the desired axis. The percent correction of preoperative astigmatism in the proper axis was 97.1 +/- 15.5%. Spectacle-corrected visual acuity improved by 2 lines in 11 eyes (9.7%), and was reduced by 1 line only in 1 eye. There were no other significant complications. CONCLUSION: LASIK with the Chiron-Technolas Keracor 116 excimer laser was effective for correction of myopic astigmatism, with good stability after 3 months. The results were predictable with an acceptable degree of accuracy. LASIK is a safe procedure with very few complications.     

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.     

Customized LASIK treatment for myopia: relationship between preoperative higher order aberrations and refractive outcome

PURPOSE: To analyze the effect of preoperative higher order aberrations on postoperative sphere and cylinder outcome. METHODS: Three hundred thirty myopic eyes (mean: -3.32 +/- 1.54 diopters [D], range: -1.0 to -7.0 D) treated with customized ablation using the Technolas 217z laser (Bausch & Lomb) were followed through 6 months after LASIK. Pre- and postoperative visual acuity, higher order root mean square (RMS), third order RMS, and spherical aberration were compared to study the safety and efficacy of the treatment. The relationship between preoperative higher order aberrations and manifest refraction after LASIK was analyzed. RESULTS: Following LASIK, 91.5% of eyes obtained an uncorrected visual acuity of > or = 20/20 and 70.3% of eyes obtained 20/16 without retreatment; 99% had a best spectacle-corrected visual acuity of > or = 20/20 (75.9% of eyes were within +/- 0.50 D). Mean value of significant increase in postoperative higher order aberrations was 0.12 +/- 0.18 microm (P<.0001). Increased spherical aberration was associated with increased myopia treatment (P<.0001). Greater positive spherical aberration after LASIK was significantly correlated to postoperative hyperopia (overcorrection). Change in third order RMS was significantly correlated to change in spherical equivalent refraction among eyes with postoperative astigmatism (P<.0001). CONCLUSIONS: With the Bausch & Lomb Technolas 217z Zyoptix software, treatment of higher order aberrations, especially third order (coma and trefoil) and spherical aberration, significantly improved postoperative refractive status.     

LASIK for hyperopia with the WaveLight excimer laser

PURPOSE: To evaluate the safety and efficacy of the ALLEGRETTO WAVE excimer laser system (WaveLight Laser Technologie AG, Erlangen, Germany) in LASIK for hyperopia and hyperopic astigmatism. METHODS: One hundred twenty consecutive LASIK cases for hyperopia with or without astigmatism treated with the ALLEGRETTO WAVE excimer laser were prospectively evaluated up to 12 months postoperatively. Patients were allocated into three groups according to their refractive sphere and cylinder: a low hyperopia group, with up to +3.00 diopters (D) sphere and astigmatism < or = +1.00 D (n = 52); a moderate hyperopia group with +3.25 to +5.00 D sphere and astigmatism of < or = +1.00 D (n = 45); and a high hyperopia/toric group with sphere > or = +5.25 D or cylinder > or = +1.25.D (n = 23). Flaps were created with the Moria M2 microkeratome (Moria, Antony, France). Parameters evaluated were pre- and postoperative refractive error, uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), higher order aberration change, and contrast sensitivity. RESULTS: One hundred twelve eyes (93%) were available for follow-up at 12 months. Of the eyes in the low hyperopia group, 92% were within +/- 0.50 D of the refractive goal. For the moderate sphere group and the high hyperopia/toric group, 79% and 71% of eyes, respectively, were within +/- 0.50 D of the refractive goal. No eye lost > or = 2 lines of BSCVA. An increase in higher order aberrations was noted in the high hyperopia/toric group from 0.47 microm (+/- 0.096) to 0.94 microm (+/- 0.167) (P < .001). No significant changes in higher order aberrations were noted in the low and moderate hyperopia groups. CONCLUSIONS: Hyperopic LASIK using the WaveLight ALLEGRETTO WAVE excimer laser appears to be safe and effective in the correction of low, moderate, and high hyperopia and hyperopic astigmatism.     

Laser in situ keratomileusis for hyeropia and hyperopic astigmatism.

PURPOSE: To evaluate the efficacy, stability, and safety of laser in situ keratomileusis (LASIK) for hyperopia and hyperopic astigmatism using a prospective clinical trial. METHODS: LASIK was performed using the Automatic Corneal Shaper and the Keracor 117C excimer laser on 192 hyperopic eyes with astigmatism of less than 1.00 D (spherical group) and 164 hyperopic eyes with corneal astigmatism of 1.00 to 7.50 D (toric group). RESULTS: At 12 months after LASIK, 110 eyes were available for follow-up examination. In low spherical hyperopia (+1.00 to +3.00 D), 13 eyes (55%) were within +/-0.50 D of emmetropia and none lost 2 or more lines of spectacle-corrected visual acuity. In low toric hyperopia (+1.00 to +3.00 D), 14 eyes (61%) were within +/-0.50 D and none lost 2 or more lines of spectacle-corrected visual acuity. In moderate spherical hyperopia (+3.10 to +5.00 D) 9 eyes (44%) were within +/-0.50 D and none lost 2 or more lines of spectacle-corrected visual acuity and in moderate toric hyperopia (+3.10 to +5.00 D) 5 eyes (36%) were within +/-0.50 D and 2 eyes (14%) lost 2 or more lines of spectacle-corrected visual acuity. In high spherical hyperopia (+5.10 to +9.00 D), 6 eyes (38%) were within +/-0.50 D and 2 eyes (13%) lost 2 or more lines of spectacle-corrected visual acuity, and in high toric hyperopia (+5.10 to +9.50 D) 4 eyes (31%) were within +/-0.50 D and 2 eyes (15%) lost 2 or more lines of spectacle-corrected visual acuity. CONCLUSIONS: LASIK seems to be reasonably effective and safe in spherical hyperopia of +1.00 to +5.00 D but less effective for hyperopic astigmatism. For hyperopia greater than +5.00 D, loss of spectacle-corrected visual acuity occurred in a significant number of eyes and accuracy was sufficiently poor to advise against LASIK in these eyes.     

Laser in situ keratomileusis for hyperopia and hyperopic astigmatism using the Meditec MEL 70 spot scanner

PURPOSE: To evaluate safety, predictability, efficacy, and stability of laser in situ keratomileusis (LASIK) for spherical hyperopia and hyperopia with astigmatism. METHODS: In this retrospective study we analyzed the results of 23 eyes of 23 patients who had LASIK for spherical hyperopia (preoperative cylinder < or = 0.75 D) and 44 eyes of 44 patients who had LASIK for hyperopia with astigmatism; (Bausch & Lomb Hansatome microkeratome with a 180-microm plate and a suction ring for a 9.5-mm flap diameter; Asclepion-Meditec MEL 70 G-scan flying spot laser with a 1.8-mm Gaussian beam). RESULTS: In Group 1 (spherical hyperopia), mean preoperative spherical equivalent refraction was +4.88 +/- 2.13 D (range +2.13 to +9.63 D); in Group 2 (hyperopic astigmatism), +4.33 +/- 2.15 D (range +0.50 to +9.50 D). One year after LASIK, mean spherical equivalent refraction was +0.30 +/- 0.90 D (range -0.75 to +2.50 D) in Group 1 and +0.29 +/- 1.27 D (range -3.25 to +3.25 D) in Group 2. In Group 1, 78%, and in Group 2, 42% were within +/- 0.50 D. In Group 1, no eyes lost two or more lines, and one eye (6%) lost one line of best spectacle-corrected visual acuity at 1 year. In Group 2, one eye (4%) lost one line and one eye (4%) lost more than two lines at 1 year. Uncorrected visual acuity of 20/40 or better was achieved in 83% (Group 1) vs. 62% (Group 2) at 1 year; these values improved to 100% vs. 71% for corrections up to +6.00 D. CONCLUSIONS: LASIK with the Meditec MEL 70 G-Scan flying spot laser seemed to be safe and effective for hyperopia and hyperopia with astigmatism for corrections up to +6.00 D. Large flap diameters are necessary to avoid epithelial ingrowth.     

Undersurface ablation of the flap for laser in situ keratomileusis retreatment

OBJECTIVE: To develop a novel technique, undersurface ablation of the flap (UAF), for laser in situ keratomileusis (LASIK) retreatment in eyes with insufficient posterior stroma. DESIGN: Noncomparative, interventional case series. PARTICIPANTS: From 30 eyes examined, 25 eyes with a spherical equivalent residual refraction between -0.75 and -3.25 diopters (D) and astigmatism between 0.0 and -1.5 D were prospectively included in the study. In these eyes, calculated postenhancement flap thickness was >150 micro m using micropachymetric optical coherence tomography (OCT), whereas with further ablation of the bed, posterior stromal thickness would have been <250 micro m. Primary LASIK procedures had been performed with the Hansatome microkeratome. INTERVENTION: The flap was lifted and the eye deviated downward, so that the corneal visual axis mark aligned with the laser beam. Mirror pattern ablations with an optical zone of 5 mm were performed on the flap stroma using either the Summit Apex Plus excimer laser or the Technolas Keracor 217 spot-scanning excimer laser. New axis orientation for toric ablations was calculated with the formula: beta = 180 degrees - alpha. MAIN OUTCOME MEASURES: Refraction, visual acuity, OCT pachymetry, tangential videokeratography, and patient satisfaction. RESULTS: The average follow-up was 6.36 +/- 2.64 months (range, 3-12 months). Mean preenhancement spherical equivalent (-2.05 +/- 0.75 D) was reduced to -0.19 +/- 0.38 D at the last visit (P = 0.001). Mean cylinder decreased from -0.48 +/- 0.53 D before retreatment to -0.23 +/- 0.28 D at the last follow-up (P = 0.003). Best-corrected visual acuity worsened by 1 line in two eyes (8%), and no eye lost 2 or more lines. Satisfactory globe stabilization and stromal smoothness during ablation were more difficult to achieve than with conventional LASIK enhancements. The average central flap thickness before UAF, 187 +/- 13 micro m, decreased to 164 +/- 12 micro m after 1 month (P = 0.001). No keratectasia developed. Finally, 92% of cases were satisfied with surgery compared with 48% before UAF retreatment (P = 0.001). CONCLUSIONS: UAF retreatment for low residual refractive errors after LASIK in eyes with sufficient flap stroma seems to be effective and may prevent future keratectasia.     

Laser in situ keratomileusis outcomes following radial keratotomy, astigmatic keratotomy, photorefractive keratectomy, and penetrating keratoplasty

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) to enhance refractive status following other corneal surgical procedures. SETTING: Clinical office-based practice. METHODS: Seventy-one eyes of 57 patients had LASIK for refractive errors following radial keratotomy (n = 22), astigmatic keratotomy (n = 13), photorefractive keratectomy (n = 18), and penetrating keratoplasty (n = 18). A Moria LSK-1 microkeratome was used with a Visx S2 or Wavelight Allegretto excimer laser. Data were acquired by retrospective chart review of all appropriately qualified patients. RESULTS: The mean preoperative manifest refractive spherical equivalent (MRSE) was -3.93 diopters (D) +/- 2.83 (SD) in myopic eyes and +1.43 +/- 1.79 D in hyperopic eyes. The mean time from the initial corneal surgical procedure to LASIK was 65.0 months. The mean post-LASIK follow-up was 9.40 months (range 1 to 42 months). Postoperatively, the mean MRSE was -0.85 +/- 1.42 D in myopic eyes (P<.0001) and -0.16 +/- 1.09 D in hyperopic eyes (P<.0001). Enhancement by LASIK was required in 14% of eyes. CONCLUSION: In eyes that have had a variety of previous corneal surgeries, LASIK offers a safe and predictable method for enhancing refractive results.     

Flap-induced refraction change in LASIK after penetrating keratoplasty

PURPOSE: To further analyze the refractive and topographic changes occurring with microkeratome lamellar keratotomy and to investigate possible factors associated in eyes with previous penetrating keratoplasty (PK). METHODS: The Hansatome microkeratome was used to create a lamellar corneal flap in 21 eyes of 19 patients after PK. The laser ablation was not performed in the first stage. Pre- and postoperative refractions and corneal topographies were compared to evaluate possible changes induced by the keratotomy. RESULTS: Twenty-one eyes were analyzed in this study. Mean time between PK and lamellar keratotomy was 36.63 +/- 28.23 months (range: 12 to 120 months). No microkeratome-related flap complications occurred. Previous to the keratotomy, the mean spherical equivalent refraction was -4.26 +/- 3.41 diopters (D), mean refractive astigmatism was -4.71 +/- 2.27 D, and mean topographic astigmatism was 5.28 +/- 2.94 D. After keratotomy, eyes showed statistically significant changes in spherical equivalent refraction from preoperative values (P = .025), with 3 eyes showing changes > 2.00 D. Average refractive and topographic astigmatism did not change significantly from before to after keratotomy. However, surgically induced astigmatism (SIA) calculated through vector analysis was > 1.01 in 11 (52.4%) eyes. A statistically significant correlation was found between the SIA values and preoperative refractive astigmatism (P = .025). CONCLUSIONS: Lamellar keratotomy as part of two-stage LASIK in eyes with prior PK led to refractive changes that justify the use of this technique, especially in eyes with high degrees of preoperative astigmatism.     

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.     

Phototherapeutic keratectomy in patients with recurrent corneal epithelial erosions

PURPOSE: To evaluate the outcome of phototherapeutic keratectomy (PTK) in the management of recurrent corneal erosions, refractory to other forms of treatment. METHODS: Phototherapeutic keratectomy was performed on 43 eyes of 41 patients with recurrent corneal erosions. The corneal epithelium was debrided, and laser ablation was performed to a depth of 6 microm with an ablation zone of 7 to 9 mm, using the Technolas Keracor 117C PlanoScan excimer laser. Follow-up time was 12 to 48 months (mean, 23.3+/-9.1 mo). RESULTS: After PTK, patients were free of symptoms in 31 eyes (72.1%), and eight eyes (18.6%) had occasional mild symptoms of irritation and photophobia upon awakening. Recurrence of painful corneal erosions occurred in four eyes (9.3%). After PTK retreatment, these patients did not report any further episodes and were free of symptoms for 12 to 30 months (mean, 21.0+/-7.7 mo). The mean spherical equivalent manifest refraction was changed by +0.15+/-0.39 D in the hyperopic direction at 1 year after PTK. Thirty-three eyes (76.7%) were within +/-1 line of preoperative best spectacle-corrected visual acuity (BSCVA). BSCVA was improved by two or more lines in 10 eyes (23.3%). There were no significant complications. CONCLUSION: Excimer laser PTK with the Technolas Keracor 117C excimer laser was a safe and effective procedure for the treatment of recurrent corneal erosions. Excimer laser PTK can also be useful in improving the visual acuity in these patients. A small percentage of patients may require a second PTK to prevent further episodes of corneal erosions.