LASIK For High Myopia Research Articles

Wavefront-guided photorefractive keratectomy after LASIK for high myopia

In this report, we discuss a case of a high myopic patient who underwent mechanical LASIK surgery in 2008 that respected the Randleman criteria for ectasia risk but incurred in a percentual thickness alteration (PTA) over 40%. The patient underwent reoperation in 2016 to correct the residual refractive error with wavefront-guided photorefractive keratectomy. At the time of the first surgery, the concept of PTA did not exist. Currently, a PTA that exceeds 35%–40% correlates with an increased risk of ectasia. We reviewed the literature focusing on the differences between the current rationale for post-LASIK enhancement and the selected strategy at the first reintervention. The purpose of this provocative case report is to emphasize the importance of personalized surgery in reoperations, always aiming for the welfare and best vision for the patient.

Long-term Visual and Refractive Outcomes After LASIK for High Myopia and Astigmatism From −8.00 to −14.25 D

To evaluate outcomes of high myopic LASIK using the MEL 80 excimer laser (Carl Zeiss Meditec, Jena, Germany). Retrospective analysis of 479 consecutive high myopic LASIK procedures (318 patients) using the MEL 80 excimer laser and VisuMax femtosecond laser (Carl Zeiss Meditec) in 77% of cases or zero compression Hansatome microkeratome (Bausch & Lomb, Rochester, NY) in 23% of cases. Inclusion criteria were preoperative spherical equivalent refraction (SEQ) of between -8.00 and -14.25 diopters (D) and corrected distance visual acuity (CDVA) of 20/20 or better. Patients were observed for a minimum of 1 year. Flap thickness was between 80 and 160 µm and optical zone was between 5.75 and 6.50 mm. Standard outcomes analysis was performed. Mean attempted SEQ was -9.39 ± 1.22 D (range: -8.00 to -14.18 D) and mean cylinder was -1.03 ± 0.84 D (range: 0.00 to -4.50 D). Mean age was 37 ± 9 years (range: 21 to 60 years) with 54% female patients. Postoperative SEQ was ±0.50 D in 55% and ±1.00 D in 83% of eyes after primary treatment. After re-treatment, 69% of eyes were within ±0.50 D and 95% were within ±1.00 D. UDVA was 20/20 or better in 89% of eyes after final treatment. One line of CDVA was lost in 3% of eyes and no eyes lost two or more lines. Statistically significant increases (P < .001) were measured in contrast sensitivity (CSV-1000) at 12 and 18 cycles per degree. The MEL 80 excimer laser was found to achieve high efficacy and safety for treatment of high myopia between -8.00 and -14.25 D and up to -4.50 D of cylinder. [J Refract Surg. 2016;32(5):290-297.].

Corneal Higher Order Aberrations After LASIK for High Myopia With a Fast Repetition Rate Excimer Laser, Optimized Ablation Profile, and Femtosecond Laser–assisted Flap

To evaluate corneal higher order aberrations (HOAs) after LASIK for the correction of high myopia using a new generation of excimer laser (500-Hz repetition rate) and optimized ablation profiles. Retrospective consecutive study including 29 eyes from 17 patients (age range: 24 to 61 years) with high levels of myopia (spherical equivalent refraction ≥8.50 diopters). All cases underwent LASIK using the sixth-generation Amaris (SCHWIND eye-tech-solutions) excimer laser and flap creation with the IntraLase (Abbott Medical Optics) femtosecond laser. Postoperative changes in corneal HOAs and corneal asphericity were analyzed during 6-month follow-up. Significant improvement in uncorrected distance visual acuity and spherical equivalent was observed (P<.01). Corrected distance visual acuity did not change after surgery (P=.37). Significant increases in corneal root-mean-square (RMS) HOA, RMS spherical aberration (SA), and RMS coma were observed 6 months after surgery (P<.01). Corneal asphericity for the 4.5-mm (Q45) and 8-mm (Q8) corneal diameter also increased significantly during the postoperative period (P<.01). Significant correlations were found between postoperative RMS HOA and RMS SA and RMS coma (r(2)=0.375, P=0.000 and r(2)=0.596, P=.000, respectively). Linear regression analysis showed a significant relationship between postoperative Q45 and preoperative pachymetry and treatment optical zone (R(2)=0.24, P<.05). A correlation was also found between postoperative Q8 and preoperative sphere and treatment ablation zone (R(2)=0.459, P<.006). A significant induction of corneal HOAs still exists with the latest generation Schwind excimer laser. Linear regression analysis will help predict postoperative asphericity obtained when using LASIK for the correction of high myopia.

LASIK for −6.00 to −12.00 D of Myopia with up to 3.00 D of Cylinder Using the ALLEGRETTO WAVE: 3- and 6-Month Results with the 200- and 400-Hz Platforms

To report the refractive results after LASIK for high myopia and cylinder at one center with one surgeon comparing two laser platforms. A total of 206 eyes of 121 patients were treated for -6.00 to -12.00 diopters (D) of spherical equivalent refractive error with up to 3.00 D of cylinder. All eyes underwent LASIK with the ALLEGRETTO WAVE 200-Hz (n=141) or 400-Hz (n=65) laser (Alcon Laboratories Inc) between 2003 and 2009. Corneal flaps were created with the IntraLase femtosecond laser (Abbott Medical Optics) at an intended thickness of 100 or 110 μm in all cases. At 3- and 6-month follow-up in the 200-Hz group, 77% (109/141) and 86% (121/141) of eyes, respectively, were within ±0.50 D of intended correction. In the 400-Hz group, 98.5% (64/65) and 100% (65/65) of eyes were within ±0.50 D of intended correction at 3 and 6 months postoperatively. At 3- and 6-month follow-up, 84% (119/141) and 77% (109/141) of eyes, respectively, in the 200-Hz group and 80% (52/65) and 92% (60/65) of eyes, respectively, in the 400-Hz group had 20/20 or better uncorrected distance visual acuity. At 6-month follow-up, refractive predictability and visual acuity were statistically superior in eyes in the 400-Hz group (chi square, P<.01). No eyes underwent retreatment as a secondary procedure during the time of analysis. LASIK with the ALLEGRETTO WAVE 200- and 400-Hz laser is effective and predictable for the treatment of high myopia with astigmatism in appropriately selected patients. The acuity and predictability of refractive results may be slightly better when using the 400-Hz platform.

Corneal recovery after lasik for high myopia: a 2-year prospective confocal microscopic study

Corneal recovery after lasik for high myopia: a 2-year prospective confocal microscopic study

Corneal recovery after lasik for high myopia: a 2-year prospective confocal microscopic study

Aim:To quantify human corneal recovery after moderate to high myopic laser in situ keratomileusis (LASIK) in a 2-year prospective follow-up study.Methods:Fifteen eyes of 15 patients (mean refraction −10.1 (SD 2.4)...

Long‐term results of LASIK in the correction of high myopia

Abstract Purpose: LASIK is widely used in the correction of moderate and high myopia, even though reports on long‐term results are few. We carried out this study to evaluate long‐term results, stability and patient satisfaction after LASIK for high myopia. Methods: The study included 77 eyes of 47 patients who underwent LASIK for myopia of over ‐10 D in our hospital in the years 1999 to 2003. Preoperative and early postoperative data, including uncorrected and best corrected visual acuity and refraction, were collected retrospectively from hospital files. An additional examination with satisfaction query was performed 2 to 5 years after the operation. Results: After a follow‐up of 2 to 5 years, 40% of the patients were within 1.0 D from the original intended refraction, 70% within 2.0 D, and 91% within 3.0 D. Only one eye lost 2 Snellen lines of visual acuity, while 3 eyes gained two lines and the rest had no significant change. Regression was mild but statistically significant in long term, with mean spherical equivalent being ‐1.2 D at one month, ‐1.8 D at 6 months, and ‐1.9 D at two to five years. Nine eyes had mild postoperative complications which all resolved without permanent consequences, and none developed keratectasia. All except one patient were very satisfied with the results, and would have chosen the operation again. Conclusions: In conclusion, with careful patient selection and safety precautions, LASIK is a safe and relatively predictable alternative in the treatment of myopia of ‐10 to ‐17 D.

Subjective and objective measures of quality of vision and their relation to simulated night driving performance after LASIK for high myopia

Subjective and objective measures of quality of vision and their relation to simulated night driving performance after LASIK for high myopia

Retinal nerve fiber layer measurements do not change after LASIK for high myopia as measured by scanning laser polarimetry with custom compensation

Scanning laser polarimetry (SLP) estimates retinal nerve fiber layer (RNFL) thickness through measurement of retardation of polarized light passing through the birefringent RNFL and cornea. A compensation method is incorporated to eliminate the anterior segment contribution to the total birefringence measured. LASIK is a technique that corrects myopia by ablating corneal tissue. This study evaluated RNFL measurements before and after LASIK as determined by SLP with a new custom compensation device set for the individual cornea before and after ablation. Interventional case series. Patients underwent SLP measurements before and 30 days after LASIK for high myopia with customized compensation for anterior segment birefringence. Postoperative measurements were obtained with both the same compensation as was used preoperatively and with newly determined customized compensation. Standard RNFL parameters obtained before and after ablation with customized compensation were compared by use of paired Student's t tests with Bonferroni's correction for multiple comparisons. Postoperative measurements were also compared with those obtained preoperatively with the same corneal compensation measures as used preoperatively. Retinal nerve fiber layer parameters as determined by SLP before and after LASIK with 2 custom cornea compensator settings postoperatively. Fifty-seven eyes of 29 patients with myopia > -5.00 diopters underwent LASIK (average central ablation depth 101+/-11.3 mum). None of the 13 parameters showed statistically significant differences between preoperative and postoperative values with individually determined corneal compensation. When the preoperative corneal compensation was used postoperatively, 10 of 13 parameters were significantly changed. Comparison of the compensator settings before and after LASIK showed substantial differences in some individuals. On the average, there was a statistically significant change in the slow polarization axis of the cornea, with no statistically significant change in the magnitude of the birefringence, with some eyes showing increases and others decreases. The change in an individual cornea could not be predicted. Changes in RNFL measurements by SLP observed after LASIK in patients with high myopia are due to changes in corneal birefringence. These RNFL changes are not seen when customized compensation is applied for the cornea. Thus, LASIK does change the corneal birefringence but does not affect the RNFL.