LASIK for Hyperopia With the WaveLight Excimer Laser

Factors Predicting Slow Visual Recovery Following Hyperopic LASIK

PURPOSE

To identify factors predicting slow visual recovery following hyperopic laser in situ keratomileusis (LASIK).

METHODS

The study included consecutive patients who underwent hyperopic LASIK between January 2005 and December 2019 at a single medical center. Patients were divided into two groups according to whether they experienced normal recovery of visual acuity (1-week visit) or slow visual recovery (1-month visit). Visual recovery was defined as achieving an efficacy index of 0.9 or greater. Efficacy index was calculated as postoperative uncorrected distance visual acuity / preoperative corrected distance visual acuity. A comparison of baseline and intraoperative parameters was performed. Binary logistic regression was performed to identify potential predictors of slow visual recovery.

RESULTS

Overall, 861 eyes of 861 patients were included. Mean age was 48.0 ± 9.5 years and 55.9% were women. Two hundred forty-nine patients (28.9%) experienced slow visual recovery. Younger age (P = .01), a larger preoperative spherical equivalence (P = .002), and greater maximum ablation depth (P = .002) were predictors of slow visual recovery. In binary logistic regression, female gender (P = .036) and greater spherical equivalence (P = .007) remained significant predictors of slow visual recovery.

CONCLUSIONS

Female gender and greater preoperative spherical equivalence were associated with slow visual recovery. Patients may be advised accordingly. [J Refract Surg. 2024;40(1):e42-e47.].

Factors Predicting Slow Visual Recovery Following Hyperopic LASIK

PURPOSE

To identify factors predicting slow visual recovery following hyperopic laser in situ keratomileusis (LASIK).

METHODS

The study included consecutive patients who underwent hyperopic LASIK between January 2005 and December 2019 at a single medical center. Patients were divided into two groups according to whether they experienced normal recovery of visual acuity (1-week visit) or slow visual recovery (1-month visit). Visual recovery was defined as achieving an efficacy index of 0.9 or greater. Efficacy index was calculated as postoperative uncorrected distance visual acuity / preoperative corrected distance visual acuity. A comparison of baseline and intraoperative parameters was performed. Binary logistic regression was performed to identify potential predictors of slow visual recovery.

RESULTS

Overall, 861 eyes of 861 patients were included. Mean age was 48.0 ± 9.5 years and 55.9% were women. Two hundred forty-nine patients (28.9%) experienced slow visual recovery. Younger age (P = .01), a larger preoperative spherical equivalence (P = .002), and greater maximum ablation depth (P = .002) were predictors of slow visual recovery. In binary logistic regression, female gender (P = .036) and greater spherical equivalence (P = .007) remained significant predictors of slow visual recovery.

CONCLUSIONS

Female gender and greater preoperative spherical equivalence were associated with slow visual recovery. Patients may be advised accordingly. [J Refract Surg. 2024;40(1):e42-e47.].

Long-term results of hyperopic ablations using alcohol-assisted PRK and FS-LASIK: comparative study

PURPOSE

To evaluate the long-term visual and refractive outcomes of hyperopic excimer ablation using alcohol-assisted photorefractive keratectomy (PRK) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK).

SETTING

American University of Beirut Medical Center, Beirut, Lebanon.

DESIGN

Retrospective, matched comparative study.

METHODS

Eyes that underwent alcohol-assisted PRK were compared to matched eyes that underwent FS-LASIK. All patients were followed up for at least 3 years after surgery. The refractive and visual outcomes of each group were compared at different postoperative time points. The main outcome measures were spherical equivalent deviation from target (SEDT), manifest refraction, and visual acuity.

RESULTS

83 eyes underwent alcohol-assisted PRK and 83 matched eyes underwent FS-LASIK. Preoperative manifest refraction spherical equivalent was 2.44 ± 1.18 diopters (D) and 2.20 ± 0.87 D ( P = .133) in the PRK and FS-LASIK groups, respectively. Preoperative manifest cylinder was -0.77 ± 0.89 D and -0.61 ± 0.59 D ( P = .175) for the PRK and LASIK groups, respectively. 3 years postoperatively, SEDT was 0.28 ± 0.66 D and 0.40 ± 0.56 D for the PRK and LASIK groups, respectively ( P = .222), whereas manifest cylinder was -0.55 ± 0.49 D and -0.30 ± 0.34 D for PRK and LASIK, respectively ( P < .001). The mean difference vector was 0.59 ± 0.46 for PRK and 0.38 ± 0.32 for LASIK ( P < .001). 13.3% of PRK eyes and 0% of LASIK eyes had >1 D of manifest cylinder ( P = .003).

CONCLUSIONS

Both alcohol-assisted PRK and FS-LASIK are safe and effective for the treatment of hyperopia. PRK induces slightly more postoperative astigmatism than LASIK. Larger optical zones and recently introduced ablation profiles that lead to a smoother ablation surface might improve the clinical results of hyperopic PRK.

One-year follow-up of patients with hyperopia undergoing photorefractive keratectomy with Allegretto WaveLight Eye Q 400

This study aimed to examine the effectiveness of photorefractive keratectomy (PRK) in treating patients with cycloplegic hyperopia from +1.00 to +7.00 diopter using Allegretto wave Eye Q 400. This study was conducted on 25 patients with cycloplegic astigmatism ≤1 diopter and cycloplegic hyperopia between +1.00 and +7.00 diopters in 47 eyes, who successively entered into the study within 6 months and underwent PRK. Prior to PRK surgery, all the patients were examined for cycloplegic refraction (astigmatism and hyperopia), slit lamp, keratometry, fundus, and best-corrected (BCVA) and uncorrected visual acuity (UCVA) testing. These examinations were repeated after 1 week, 1 month, 3 months, 6 months, and 1 year postoperatively. The mean preop UCVA of patients was 0.76±0.28 (ranging from 0.00 to 1.3), which reached 0.19±0.22 (ranging from 0.00 to 0.78) one year after the surgery (P=0.000). There was a significant correlation between increasing astigmatism and preop cycloplegic hyperopia >5 diopters (P=0.000), corneal ring haziness at 12^th months (P=0.000), and 12 months cycloplegic residual hyperopia ≥2.00 diopters (P=0.000). 53.2% of the eyes (with a mean grade of 2.34) were detected with corneal ring haziness at 12^th months, which was significantly correlated with 12 months residual cycloplegic hyperopia of ≥2.00 diopters (P: 0.000) and cycloplegic sphere above 5 diopters (P=0.006). Although the use of photorefractive keratectomy (PRK) with Allegretto Eye Q 400 is associated with a decrease in the mean cycloplegic and improved UCVA and BCVA, its use is not recommended in cases with preop cycloplegic hyperopia above 5 diopters due to the high rate of induction of astigmatism, corneal haziness, and regression of hyperopia.

Comparison of Visual Outcome After Hyperopic LASIK Using a Wavefront-Optimized Platform Versus Other Excimer Lasers in the Past Two Decades

Introduction

Laser-assisted in-situ keratomileusis (LASIK) for the correction of hyperopia and hyperopic astigmatism is challenging and has been less studied than for the correction of myopia and myopic astigmatism. The aim of this study was to analyze the refractive outcomes of LASIK in hyperopia and hyperopic astigmatic eyes using a wave-front optimized laser platform (the Allegretto EX500 laser) and perform a historical comparison with other excimer lasers within the past two decades.

Methods

A one-center (Tertiary Refractive Center, Draper, Utah), retrospective, non-comparative study was conducted on 379 eyes treated with LASIK for hyperopia and hyperopic astigmatism. The data retrieved on these eyes were analyzed using uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and spherical equivalents. A literature search of excimer platforms in use in the past 20 years and a comparison of US Federal Drug Administration-approved platforms for hyperopia were performed.

Results

At 3 and 12 months postoperatively, 142 (66%) and 81 (69%) eyes had a UDVA of 20/20 or better and 207 (96%) and 114 (97%) eyes had a UDVA of 20/40 or better, respectively. The mean refractive spherical equivalent was − 0.52 ± 0.78 D at 3 months and − 0.46 ± 0.79 D at 12 months. At 12 months, 181 (96%) eyes achieved a spherical equivalent within ± 1.00 D of the intended target. Studies published before 2005 reported lower rates of UDVA 20/20 or better (32%) compared to those published after (68%); however, this discrepancy was less evident for UDVA 20/40 or better. A similar trend towards improved accuracy was noted in the literature with postoperative manifest refractive spherical equivalent within ± 0.50 D before and after 2005.

Conclusion

There has been significant improvement in safety, efficacy, stability, and accuracy of LASIK treatment for hyperopia and hyperopic astigmatism within the past two decades. Newer excimer lasers meet industry standards and in particular, the Allegretto EX500 used in this study exceeded industry standards.

Femtosecond-LASIK outcomes using the VisuMax®-MEL® 80 platform for hyperopia and hyperopic astigmatism refractive surgery

The present study evaluated the efficacy, the safety and the predictability of the Femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) procedure for hyperopia and hyperopic astigmatism. We retrospectively analyzed the postoperative 12-month evolution of 593 eyes with hyperopia and hyperopic astigmatism that underwent Femto-LASIK treatment. The procedure was predictable and effective. No eye lost 2 lines of corrected distance visual acuity (CDVA), demonstrating a safety profile of the procedure. Nine percent of the eyes gained at least one line of CDVA. The accuracy of the spherical equivalent after 12 months was 74% within ±1.0 diopter (D) of emmetropia. The refractive outcomes were stable during the follow-up period. There were no significant complications during the procedure. Femto-LASIK using the VisuMax^®-MEL^® 80 platform was demonstrated to be a suitable option to correct selected cases of hyperopia and hyperopic astigmatism. A longer follow-up period is required to better assess the refractive results and to detect any further regression.

Three-Month Outcomes of Laser Vision Correction for Myopia and Hyperopia in Adults With Amblyopia

PURPOSE

To evaluate the visual outcomes of laser vision correction in adults with myopic and hyperopic amblyopia.

METHODS

The medical records of patients diagnosed as having amblyopia who underwent laser refractive surgery between February 2013 and October 2017 were retrospectively reviewed. Eyes with amblyopia were analyzed, and the nonamblyopic fellow eyes of the patients who underwent laser vision correction were used as controls. The uncorrected distance visual acuity (UDVA), subjective manifest refraction, and corrected distance visual acuity (CDVA) were analyzed at the 3-month postoperative time point.

RESULTS

This study included 323 eyes of 164 patients. All patients underwent laser in situ keratomileusis (90.1%, 291 eyes) or photorefractive keratectomy (9.9%, 32 eyes). Three months postoperatively, the manifest spherical equivalent was -0.07 ± 0.55 diopters (D) (range: -1.75 to +1.30 D) and -0.10 ± 0.54 D (range: -2.13 to +1.30 D) in the amblyopia group and fellow eye group, respectively. The percentage of eyes achieving UDVA of 20/20 or better was 16.9% (15 eyes) in the amblyopia group and 61.9% (52 eyes) in the fellow eye group. The percentage of eyes that gained two or more lines of CDVA was 27.9% (24 eyes) in the amblyopia group and 6.2% (5 eyes) in the fellow eye group (P < .01). In the amblyopia group, there was no statistically significant difference in the mean manifest spherical equivalent between the myopic eyes and hyper-opic eyes at any follow-up visit (P = .87, 1 month postoperatively; P = .68, 3 months postoperatively).

CONCLUSIONS

Laser vision correction was found to be effective and safe in adult patients with amblyopia. [J Refract Surg. 2020;36(8):511-519.].

The relationship between patient age and residual refractive error after uneventful laser in situ keratomileusis for moderate-to-high hyperopia

PURPOSE

To determine if the manifest sphero-cylindrical residual refractive error, at various time points over a 12-month postop period after laser in situ keratomileusis (LASIK) was associated with patient age at time of surgery.

METHODS

Patients with moderate to high hyperopia (3.00-7.00 DS) and astigmatism ⩽2 DC underwent LASIK using Wavelight Allegretto Eye Q (400 Hz). Treatments were centered on corneal vertex, flaps were made with Moria M2 mechanical microkeratome. Pre-and postoperative uncorrected and corrected distant visual acuity, best corrected spherical equivalent (SEQ) were measured. Measurements were taken at 1 week, 1, 3, 6, and 12 months after the surgery. Target refraction was emmetropia. Total of 161 patients were treated. In binocular cases, data from the right eyes were included for analysis. In this article, we report on refraction data only. Raw data were subjected to several permutations to elicit any links between refractive outcomes and patient age.

RESULTS

The key findings were as follows y = postop SEQ (diopters), x = patient age (years), ln(x) = natural logarithm of patient age: At 1 month, y = x[0.049 -0.011.ln(x)] (R = -0.205, p = 0.001, n = 161). At 3 months, y = x[0.077 -0.017.ln(x)] (R = -0.355, p < 0.001, n = 161). At 6 months, y = x[0.088 -0.020.ln(x)] (R = -0.382, p < 0.001, n = 161). At 12 months, y = x[0.093 -0.021.ln(x)] (R = -0.409, p < 0.001, n = 161). There was no significant association between x and y at 1 week (p > 0.05).

CONCLUSION

Residual postop refractive error after LASIK for hyperopia has a logarithmic association with patient age at time of surgery. In younger patients there is tendency toward undercorrection, the opposite occurs in older patients and this persists 1 year after treatment.

Outcomes for Hyperopic LASIK With the MEL 90® Excimer Laser

PURPOSE

To report the outcomes of laser in situ keratomileusis (LASIK) for hyperopia using the Triple-A ablation profile with the MEL 90 excimer laser (Carl Zeiss Meditec, Jena, Germany).

METHODS

This retrospective analysis included 1,383 eyes treated by LASIK for hyperopia using the Triple-A ablation profile with the MEL 90 at London Vision Clinic, London, United Kingdom, between September 2013 and December 2016. Inclusion criteria were attempted hyperopic correction of +0.25 diopters (D) or higher and corrected distance visual acuity (CDVA) of 20/40 or better. Patients were observed for 1 year after surgery. Standard outcomes analysis was performed.

RESULTS

One-year data were available for 1,350 (97%) eyes. Mean attempted spherical equivalent refraction (SEQ) was +2.77 ± 1.34 D (range: +0.13 to +6.50 D) and mean cylinder was -0.67 ± 0.66 D (range: 0.00 to -5.00 D). Mean age was 54 ± 11 years (range: 21 to 75 years), and 57% were female. Postoperative spherical equivalent was ±0.50 D in 73% and ±1.00 D in 93% of eyes. Uncorrected distance visual acuity was 20/20 or better in 75% of eyes, relative to 93% with preoperative CDVA of 20/20 or better. One line of CDVA was lost in 17% of eyes and two lines were lost in 0.6% of eyes. There was a clinically insignificant but statistically significant increase (P < .01) in contrast sensitivity at 3 and 6 cycles per degree (cpd) and no change for 12 and 18 cpd.

CONCLUSIONS

LASIK for hyperopia with the MEL 90 excimer laser was found to satisfy accepted criteria for safety, efficacy, and stability. [J Refract Surg. 2018;34(12):799-808.].

LASIK for the Correction of High Hyperopic Astigmatism With Epithelial Thickness Monitoring

PURPOSE

To evaluate outcomes of high hyperopic LASIK using the MEL 80 excimer laser (Carl Zeiss Meditec, Jena, Germany).

METHODS

Retrospective analysis of 830 consecutive high hyperopic LASIK procedures using the MEL 80 excimer laser and either the VisuMax femtosecond laser (Carl Zeiss Meditec) or zero compression Hansatome microkeratome (Bausch & Lomb, Rochester, NY). Inclusion criteria were attempted hyperopic correction of +4.00 diopters [D] or higher in one axis and corrected distance visual acuity (CDVA) of 20/20 or better. Patients were observed for a minimum of 1 year. Epithelial thickness monitoring by Artemis very high-frequency (VHF) digital ultrasound (ArcScan Inc., Morrison, CO) was used to evaluate potential for further steepening as a re-treatment.

RESULTS

One-year data were available for 785 eyes. Mean attempted spherical equivalent refraction (SEQ) was +4.52 ± 0.84 D (range: +2.00 to +6.96 D) for the primary treatment and mean cylinder was 1.05 ± 0.86 D (range: 0.00 to 5.25 D). Mean age was 50 ± 12 years (range: 18 to 70 years) and 61% were women. Postoperative SEQ was ±0.50 D in 50% and ±1.00 D in 77% of eyes after primary treatment. After re-treatment, 67% of eyes were within ±0.50 D and 89% were within ±1.00 D. Uncorrected distance visual acuity was 20/20 or better in 76% of eyes after final treatment. One line of CDVA was lost in 25% of eyes and two lines were lost in 0.4%. There was a clinically insignificant but statistically significant decrease (P < .05) in contrast sensitivity (CSV-1000) by less than 1 log unit at 3 and 6 cycles per degree (cpd) and by 1 log unit at 12 and 18 cpd. Diurnal fluctuation in refraction was identified in 2 eyes, proven by VHF digital ultrasound to be due to diurnal epithelial remodeling overnight and unrelated to maximum postoperative keratometry induced.

CONCLUSIONS

LASIK for hyperopia by cumulative treatment of up to +8.33 D with the MEL 80 excimer laser was found to satisfy accepted criteria for safety, efficacy, and stability when applying specialized protocols, including epithelial monitoring. [J Refract Surg. 2017;33(5):314-321.].

Hyperopic Q-optimized algorithms: a theoretical study on factors influencing optical quality

In this work, we analyze the way in which pupil size, optical zone, and initial hyperopic level influence optical quality for hyperopic Q-optimized corneal refractive surgery. Different Q-optimized algorithms and the Munnerlyn formula were tested to analyze the optical quality of the final retinal image for initial hyperopic errors from 1D to 5D. Three optical zones (5.5, 6, and 6.5 mm) and two pupil diameters (5 and 7 mm) were considered. To evaluate optical quality, we computed the modulation transfer function (MTF) and the area under MTF (MTFa). Q-optimized values at around Q = -0.18 were found to provide the best optical quality for most of the conditions tested. This optimum final asphericity for hyperopic ablation was not depending on the degree of hyperopia corrected, the optical zone or the pupil size being this information important for clinical practice.

Hyperopic laser in situ keratomileusis: comparison of femtosecond laser and mechanical microkeratome flap creation

PURPOSE

To evaluate and compare the refractive predictability and stability of laser in situ keratomileusis (LASIK) flap creation performed with a femtosecond laser and with a mechanical microkeratome to correct mild to moderate hyperopia.

SETTING

American University of Beirut Medical Center, Beirut, Lebanon.

DESIGN

Retrospective case series.

METHODS

Patients who had hyperopic LASIK treatment using the Amaris excimer laser were included. Eyes in which the LDV femtosecond laser was used for flap creation were compared with eyes in which the Moria M2 microkeratome was used.

RESULTS

The microkeratome group comprised 53 eyes and the femtosecond laser group, 72 eyes. Baseline characteristics were similar between groups (P > .05). The mean spherical equivalent (SE) deviation from target 1 week postoperatively was -0.08 diopter (D) ± 0.58 (SD) in the femtosecond laser group and -0.06 ± 0.87 D in the microkeratome group (P = .92). Thereafter, the mean SE deviation from target increased gradually and by 6 months postoperatively was +0.30 ± 0.50 D and +0.70 ± 0.71 D, respectively (P = .001). The correlation between the achieved and the attempted SE refraction was better in the femtosecond laser group (R(2) = 0.806) than the microkeratome group (R(2) = 0.671).

CONCLUSIONS

Using the same nomogram, the short-term refractive outcomes of hyperopic LASIK with flap creation performed with the femtosecond laser were comparable to those for the microkeratome; however, the femtosecond group showed significantly better stability over the 6-month follow-up and better predictability, as reflected by a lower standard deviation and stronger Pearson correlation.

FINANCIAL DISCLOSURE

Dr. Arba Mosquera is an employee of Schwind eye-tech-solutions GmbH and Co. KG. No other author has a financial or proprietary interest in any material or method mentioned.

Long-Term Followup of Laser In Situ Keratomileusis for Hyperopia Using a 213 nm Wavelength Solid-State Laser

Purpose. To evaluate the long-term efficacy, accuracy, stability, and safety of hyperopic laser in situ keratomileusis (LASIK) using a 213 nm wavelength solid-state laser. Methods. This prospective noncomparative case series consisted of 34 eyes of 17 patients which underwent hyperopic LASIK using a 213 nm solid-state laser (Pulzar Z1, CustomVis) at an outpatient refractive surgery center in Manila, Philippines. The preoperative and postoperative examinations included uncorrected distance visual acuity (UDVA), subjective manifest refraction, corrected distance visual acuity (CDVA), cycloplegic refraction, slitlamp biomicroscopy, and keratometry (K). Main Outcome Measures. Accuracy, efficacy, stability, and safety of the refractive procedure. Results. Mean follow-up was 25.18 ± 13.79 months. At the end of follow-up, 26.47% had a UDVA of 20/20 and 94.12% had a UDVA of ≥20/40. Manifest refractive spherical equivalent (MRSE) was within ±0.50 D of the target refraction in 55.88% and within ±1.0 D in 85.30% of the study eyes. Refractive stability was noted in the 1st postoperative month while hyperopic regression was noted after the 3rd postoperative year. No eye lost more than 2 lines of CDVA. Conclusion. Our results show that the 213 nm solid state laser system is safe, effective, accurate, and predictable for the treatment of hyperopia.

Topography-guided hyperopic LASIK with and without high irradiance collagen cross-linking: initial comparative clinical findings in a contralateral eye study of 34 consecutive patients

PURPOSE

To evaluate the safety and efficacy of intrastromally applied collagen cross-linking (CXL) in a comparative contralateral eye study of topography-guided femtosecond laser-assisted hyperopic LASIK.

METHODS

Thirty-four consecutive patients with hyperopia and hyperopic astigmatism elected to have bilateral topography-guided LASIK and were randomized to receive a single drop of 0.1% sodium phosphate riboflavin solution under the flap followed by 3-minute exposure of 10 mW/cm2 ultraviolet A (UVA) light with the flap realigned in one eye (CXL group) and no intrastromal CXL in the contralateral eye (no CXL group). All eyes were treated with the WaveLight FS200 femtosecond laser and WaveLight EX500 excimer laser (Alcon Laboratories Inc). Refractive error and keratometric, topographic, and tomographic measurements were evaluated over mean follow-up of 23 months.

RESULTS

Preoperatively, mean spherical equivalent refraction was +3.15 +/- 1.46 diopters (D) and +3.40 +/- 1.78 D with a mean cylinder of 1.20 +/- 1.18 D and 1.40 +/- 1.80 D and mean uncorrected distance visual acuity (UDVA) (decimal) of 0.1 +/- 0.26 and 0.1 +/-0.25 in the CXL and no CXL groups, respectively. At 2 years postoperatively, mean spherical equivalent refraction was -0.20 +/- 0.56 D and +0.20 +/- 0.40 D with mean cylinder of 0.65 +/- 0.56 D and 0.76 +/- 0.72 D and mean UDVA of 0.95 +/- 0.15 and 0.85 +/- 0.23 in the CXL and no CXL groups, respectively. Eyes with CXL demonstrated a mean regression from treatment of +0.22 +/- 0.31 D, whereas eyes without CXL showed a statistically significant greater regression of +0.72 +/- 0.19 D (P = .0001).

CONCLUSIONS

Topography-guided hyperopic LASIK with or without intrastromal CXL is safe and effective, with greater long-term efficacy (less regression) in eyes with CXL. Our data suggest that the regression seen with hyperopic LASIK may be related to biomechanical changes in corneal shape over time.

Laser in situ keratomileusis for high hyperopia (>5.0 diopters) using optimized aspheric profiles: efficacy and safety

PURPOSE

To evaluate the clinical outcomes of laser in situ keratomileusis (LASIK) for high hyperopia using an excimer laser and optimized aspheric profiles.

SETTING

Vissum Corporation and Miguel Hernández University, Alicante, Spain, and Research Institute of Ophthalmology, Giza, Egypt.

DESIGN

Case series.

METHODS

Eyes of patients with high hyperopia or hyperopic astigmatism (spherical equivalent [SE] ≥ 5.64 diopters [D]) had uneventful LASIK with an aspheric optimized ablation profile centered on the corneal vertex using an Amaris 500 kHz excimer laser and a femtosecond platform for flap creation with a temporal hinge.

RESULTS

There was a significant improvement in uncorrected distance visual acuity 3 months postoperatively (P<.01), with no significant changes afterward (P=.72). At 6 months, the corrected distance visual acuity (CDVA) remained unchanged or improved in 90.48% of eyes; 2 eyes (9.52%) lost 2 lines of logMAR CDVA. The postoperative SE was within ± 0.50 D of emmetropia in 70.37% of eyes. The LASIK enhancement rate at the end of the follow-up was 29.4%. Significant induction of corneal primary spherical aberration and coma was found with 6.0 mm pupils (P<.01). The safety index was 0.94 and the efficacy index, 0.85.

CONCLUSION

Laser in situ keratomileusis for high hyperopia using optimized aspheric profiles requires further improvement in terms of safety but was still an effective and a predictable procedure.

Femtosecond laser vs mechanical microkeratome for hyperopic laser in situ keratomileusis

PURPOSE

To compare the outcomes of laser in situ keratomileusis (LASIK) performed with a femtosecond laser vs a mechanical microkeratome for the correction of low to moderate hyperopia.

DESIGN

Retrospective, nonrandomized, interventional, comparative case series.

METHODS

settings: Vissum Santa Hortensia, Madrid, Spain.study population and procedures: Patients who had undergone LASIK to correct their hyperopia using the 60-kHz IntraLase femtosecond laser were compared to age- and refraction-matched patients in whom the Moria M2 microkeratome was used. Visual and refractive results 3 months postoperatively were compared between both groups.

RESULTS

A total of 144 eyes were analyzed (72 in each group). Mean preoperative sphere was +3.45 ± 1.0 diopters (D) in the IntraLase group vs +3.18 ± 1.3 D in the M2 group (P = .1). Results 3 months postoperatively were: mean residual sphere, +0.44 ± 0.6D vs +0.72 ± 0.8 D (P = .02), respectively; uncorrected visual acuity (UCVA), 0.89 ± 0.2 vs 0.80 ± 0.2 (P = .04); best spectacle-corrected visual acuity (BSCVA), 0.96 ± 0.2 vs 0.92 ± 0.2 (P = .2); safety index, 0.97 ± 0.1 vs 0.98 ± 0.1 (P = .5); efficacy index, 0.89 ± 0.2 vs 0.84 ± 0.2 (P = .3).

CONCLUSIONS

Hyperopic LASIK performed with the IntraLase femtosecond laser seems to achieve better refractive results 3 months after the surgery compared to the M2 microkeratome, without significant differences in safety between both procedures.

Effect of air-flow on the evaluation of refractive surgery ablation patterns

An Allegretto Eye-Q laser platform (Wavelight GmbH, Erlangen, Germany) was used to study the effect of air-flow speed on the ablation of artificial polymer corneas used for testing refractive surgery patterns. Flat samples of two materials (PMMA and Filofocon A) were ablated at four different air flow conditions. The shape and profile of the ablated surfaces were measured with a precise non-contact optical surface profilometer. Significant asymmetries in the measured profiles were found when the ablation was performed with the clinical air aspiration system, and also without air flow. Increasing air-flow produced deeper ablations, improved symmetry, and increased the repeatability of the ablation pattern. Shielding of the laser pulse by the plume of smoke during the ablation of plastic samples reduced the central ablation depth by more than 40% with no-air flow, 30% with clinical air aspiration, and 5% with 1.15 m/s air flow. A simple model based on non-inertial dragging of the particles by air flow predicts no central shielding with 2.3 m/s air flow, and accurately predicts (within 2 μm) the decrease of central ablation depth by shielding. The shielding effects for PMMA and Filofocon A were similar despite the differences in the ablation properties of the materials and the different full-shielding transmission coefficient, which is related to the number of particles ejected and their associated optical behavior. Air flow is a key factor in the evaluation of ablation patterns in refractive surgery using plastic models, as significant shielding effects are found with typical air-flow levels used under clinical conditions. Shielding effects can be avoided by tuning the air flow to the laser repetition rate.

Comparing conventional and wavefront-optimized LASIK for the treatment of hyperopia

PURPOSE

To compare differences in visual outcomes and induced spherical aberration after conventional and wavefront-optimized LASIK for the treatment of hyperopia.

METHODS

In a prospective, randomized, single-center clinical trial, 51 consecutive eyes underwent LASIK for the treatment of hyperopia. Eyes were divided between groups treated with conventional LASIK with the Alcon LADAR4000 excimer laser (n=25) and wavefront-optimized LASIK with the WaveLight ALLEGRETTO excimer laser (n=26). Refractive and visual outcomes, induced spherical aberrations, and contrast sensitivity were analyzed.

RESULTS

On postoperative day 1, 20% of eyes treated with a conventional profile had uncorrected visual acuity (UCVA) of 20/20 or better compared to 65% of eyes receiving wavefront-optimized treatment (P=.0011). By 6 months, UCVA was 20/20 or better in 72% and 84% of the conventional and wavefront-optimized treatment groups, respectively (P=.3254). At 6 months, the manifest refraction spherical equivalent was -0.21+/-0.47 diopters (D) and 0.16+/-0.27 D (P=.6469) whereas the cylinder was -0.41+/-0.47 D and -0.17+/-0.27 D (P=.0332) for the conventional and wavefront-optimized treatment groups, respectively. Induced spherical aberration was -0.54+/-0.32 microm and -0.42+/-0.21 microm for the conventional and wavefront-optimized treatment groups, respectively (P=.1195). The respective change in mesopic and photopic area under the log contrast sensitivity function was -0.05+/-0.29 and -0.05+/-0.23 for the conventional treatment group and 0.08+/-0.39 and 0.08+/-0.41 for the wavefront-optimized treatment group (P=.1970).

CONCLUSIONS

Wavefront-optimized (ALLEGRETTO) and conventional (LADAR4000) ablation predictably and safely correct low to moderate hyperopia. Wavefront-optimized ablation showed superior results with regards to rapid visual recovery and residual cylinder. Although not statistically significant, a trend towards less induced negative spherical aberrations and improved mesopic and photopic contrast sensitivity was noted with wavefront-optimized treatment.

Visual acuity and higher-order aberrations with wavefront-guided and wavefront-optimized laser in situ keratomileusis

PURPOSE

To compare visual acuity and higher-order aberrations (HOAs) after wavefront-guided and wavefront-optimized laser in situ keratomileusis (LASIK).

METHODS

This retrospective study comprised refraction-matched myopic eyes that had wavefront-guided (Visx Star S4 laser) or wavefront-optimized (WaveLight Allegretto Wave laser) LASIK targeted for emmetropia. Preoperative and postoperative manifest refraction spherical equivalent (MRSE), uncorrected (UDVA) and corrected (CDVA) distance visual acuities, and preoperative and postoperative HOAs were compared.

RESULTS

Preoperatively, there were no significant differences between the wavefront-guided and wavefront-optimized groups in age, sex, corneal thickness, MRSE, or HOAs (all P>.05). The mean MRSE was -2.88 diopters (D) +/- 2.6 (SD) and -2.96 +/- 2.6 D, respectively, preoperatively and -0.01 +/- 0.25 D and -0.02 +/- 0.33 D, respectively, postoperatively; 96% of all eyes were within +/-0.50 D of emmetropia postoperatively. There were no differences in UDVA, CDVA, MRSE, or HOAs between groups (all P>.05). The UDVA was 20/20 or better in 85% of eyes in the wavefront-guided group and 86% of eyes in the wavefront-optimized group. All eyes had 20/25 or better CDVA postoperatively; no eye lost 2 lines of CDVA. Fourteen eyes were converted from wavefront-guided to wavefront-optimized treatment because of poor limbal ring alignment (8 eyes), a wave scan not consistent with the manifest refraction (5 eyes), and no iris registration (1 eye).

CONCLUSIONS

Wavefront-guided LASIK and wavefront-optimized LASIK produced equivalent visual outcomes and no differences in HOAs. Wavefront-guided treatment could not be performed in many eyes because of difficulties during wavefront measurement.

One-year results of excimer laser in situ keratomileusis for hyperopia

PURPOSE

To evaluate the visual and refractive results of hyperopic LASIK.

SETTING

Clínica Baviera Instituto Oftalmológico Europeo, Madrid, Spain.

METHODS

This retrospective consecutive noncomparative observational study evaluated hyperopic LASIK results over 1 year. Outcomes included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), cycloplegic refraction, and corneal topography. Surgery was performed using an MEL 80-G excimer laser. Results were analyzed by preoperative spherical equivalent (SE) (Group 1: <or=+3.50 diopters [D]; Group 2: >or=+3.60 D).

RESULTS

The mean UDVA improved from 0.50 +/- 0.3 (SD) to 0.90 +/- 0.2 in Group 1 and from 0.50 +/- 0.3 to 0.80 +/- 0.2 in Group 2 and the mean CDVA, from 0.86 +/- 0.2 to 0.93 +/- 0.1 and from 0.80 +/- 0.2 to 0.90 +/- 0.2, respectively. The mean cycloplegic SE improved from +2. 5+/- 0.8 to +0.1 +/- 0.5 in Group 1 and from +4.5 +/- 0.6 to +0.4 +/- 0.6 in Group 2; 70.9% of eyes and 63.3% of eyes, respectively, were within +/-0.50 D of emmetropia. Postoperatively, 92.8% of eyes in Group 1 and 87.8% in Group 2 maintained or gained 1 or more lines of CDVA; 1.7% and 4.0%, respectively, lost 2 or more lines. The safety index was 1.1 in both groups and the efficacy index, 1.01 in Group 1 and 0.98 in Group 2. The enhancement rate was 20.0% and 18.4%, respectively.

CONCLUSION

Excimer laser LASIK was safe and effective for treating hyperopia up to +6.25 D with no further loss of CDVA lines after enhancement.

LASIK for hyperopic astigmatism and presbyopia using micro-monovision with the Carl Zeiss Meditec MEL80 platform

PURPOSE

To evaluate the monocular and binocular outcomes of LASIK for a micro-monovision protocol for the correction of hyperopic astigmatism and presbyopia.

METHODS

A prospective non-comparative case series included 258 eyes of 129 consecutive patients with hyperopic astigmatism and presbyopia who were treated with LASIK-induced micro-monovision. The CRS-Master software was used to generate ablation profiles for the Carl Zeiss Meditec MEL80 excimer laser. The target refraction was piano for distance eyes (dominant eye) and between -1.00 and -1.50 diopters (D) for near eyes. Patients were followed for 1 year.

RESULTS

Mean attempted spherical equivalent refraction (SE) correction was +2.54+/-1.16 D (range: +0.25 to +5.75 D). Mean attempted cylinder was -0.52+/-0.49 D (range: -0.00 to -3.25 D). Median age was 56 years (range: 44 to 66 years). Median follow-up was 12.5 months (range: 3.3 months [early retreatment] to 18.2 months). The retreatment rate was 22%. Outcome measures after all treatments were as follows. Mean deviation from the intended SE correction was +0.09+/-0.48 D, with 79% of eyes within +/-0.50 D and 95% within +/-1.00 D. The cylinder correction ratio was 1.23+/-0.63 and the error ratio was 0.67+/-0.65. Of the distance eyes, 86% achieved uncorrected visual acuity of 20/20 and 100% achieved 20/40. Binocularly, 95% of patients achieved 20/20 and 100% achieved 20/40. Eighty-one percent of patients could read J2 and 100% could read J5. Binocularly, 95% of patients achieved 20/20 and could read J5. No eyes lost 2 or more lines of best spectacle-corrected visual acuity. A statistically significant increase was noted in contrast sensitivity at 3 and 6 cycles per degree (cpd), with no reduction at 12 and 18 cpd. The average change in refraction between 3 months and 1 year was +0.11+/-0.36 D with a change of >1.00 D in 2.6% of eyes.

CONCLUSIONS

This hyperopic micro-monovision protocol was a well-tolerated and effective procedure for treating patients with presbyopia in moderate to high hyperopia with corrections ranging up to +5.75 D. Contrast sensitivity was improved and the distance vision of near eyes was found to contribute positively to binocular distance vision compared to distance eyes monocularly.

Visual and refractive outcomes of LASIK with the SCHWIND ESIRIS and WaveLight ALLEGRETTO WAVE Eye-q excimer lasers: a prospective, contralateral study

PURPOSE

To compare the safety, efficacy, and predictability of LASIK with the SCHWIND ESIRIS and WaveLight ALLEGRETTO WAVE Eye-Q excimer laser platforms.

METHODS

This prospective study comprised 44 eyes of 22 consecutive patients who were treated with LASIK using the Moria M2 microkeratome. One eye was treated with the SCHWIND ESIRIS laser and the fellow eye treated with the WaveLight ALLEGRETTO WAVE Eye-Q laser. All eyes operated with the SCHWIND ESIRIS were treated with standard aspheric ablation, whereas the eyes operated with the WaveLight ALLEGRETTO WAVE Eye-Q received treatment with three different ablation types according to the common practice at our clinic. Outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and proximity to target refraction at 6-month follow-up.

RESULTS

At 6 months postoperative, mean decimal UCVA was 0.96+/-0.22 (range: 0.3 to 1.2) for ESIRIS eyes and 0.98+/-0.17 (range: 0.6 to 1.2) for ALLEGRETTO eyes (P=.57). Mean postoperative spherical equivalent refraction was -0.02+/-0.28 diopters (D) (range: -0.75 to +0.75 D) for ESIRIS eyes and 0.11+/-0.91 D (range: -1.00 to +3.88 D) for ALLEGRETTO eyes (P=.49). Of the ESIRIS eyes, 20/22 (91%) were within +/-1.00 D of target refraction and 20/22 (91%) were within +/-0.50 D of target refraction. Of the ALLEGRETTO eyes, 20/22 (91%) and 19/22 (86%) were within +/-1.00 D and +/-0.50 D, respectively, of target refraction. No patient lost > or =2 lines of BSCVA in either group.

CONCLUSIONS

No differences were seen in safety and efficacy outcome parameters between the SCHWIND ESIRIS and WaveLight ALLEGRETTO WAVE Eye-Q excimer lasers when used according to a previously established treatment algorithm at our clinic in the treatment of refractive error.

Four-year postoperative results of the US ALLEGRETTO WAVE clinical trial for the treatment of hyperopia

PURPOSE

To evaluate the long-term refractive stability after LASIK for hyperopia with the WaveLight ALLEGRETTO WAVE Excimer Laser System.

METHODS

All 151 patients enrolled in the 2000-2002 FDA study of the ALLEGRETTO WAVE laser were contacted by the investigators approximately 4 years after study completion to be evaluated for refractive stability.

RESULTS

A total of 127/290 (43.8%) eyes in 68/151 (45%) patients presented for re-examination. Mean time from the examination taken at the 6-month follow-up stability endpoint in the FDA trial (Stability Exam) to the Post-Approval Exam was 3.9+/-0.39 years (range: 3.2 to 4.9 years). Stability of the manifest refraction spherical equivalent (MRSE) within +/-1.00 D or less was seen in 119/127 (93.7%) eyes. Regression of effect of >1.00 D was seen in 6/127 (4.7%) eyes and progression of effect was seen in 2/127 (1.6%) eyes. Weak correlation of refractive changes with keratometry readings were seen in eyes that underwent >2.00 to 4.00 D treatment (R=0.31) and >4.00 D treatment (R=0.33), implying corneal remodeling may have played a role in the refractive change observed.

CONCLUSIONS

Refractive stability within +/-1.00 D MRSE after hyperopic LASIK with the ALLEGRETTO WAVE excimer laser was seen in 93.7% of eyes at > or =3 years after surgery compared with 6-month follow-up, supporting the conclusion in the FDA trial that refractive stability occurred by 6 months postoperatively. Refractive changes associated with keratometry changes were not significant in eyes that underwent < or =2.00-D treatment.

Corneal aberrations and objective visual quality after hyperopic laser in situ keratomileusis using the Esiris excimer laser

PURPOSE

To evaluate the changes in visual performance and ocular optical quality after hyperopic laser in situ keratomileusis (LASIK) using the Esiris excimer laser (Schwind eye-tech-solutions).

SETTING

Vissum-Instituto Oftalmológico de Alicante, Alicante, Spain.

METHODS

Excimer laser surgery was performed with the Esiris laser in 51 eyes of 29 patients with hyperopia or hyperopic astigmatism. The follow-up was 6 months. Changes in visual acuity, refraction, and corneal and ocular wavefront aberrations (6.0 mm pupil) were recorded and analyzed.

RESULTS

The mean preoperative sphere was +4.45 diopters (D)+/-1.08 (SD) (range +2.50 to +7.25 D) and the mean preoperative cylinder, -0.55+/-0.36 D (range 0.00 to 1.00 D). Ten eyes (19.61%) had a LASIK enhancement during the follow-up for the correction of the residual refractive error and were excluded from the refractive analysis. Of the 41 remaining eyes, 95.12% had the same or improved distance best spectacle-corrected visual acuity (BSCVA) 6 months after surgery; 90.25% had no change or a gain of lines of near BSCVA. Moreover, 80.50% of eyes were within +/-0.50 D of emmetropia. Regarding corneal aberrations, statistically significant changes were observed in higher-order aberrations (HOAs), coma-like aberrations, and the primary spherical aberration coefficient Z(4,0), which changed from positive to negative values (all P<.01). Regarding total ocular aberrations, statistically significant changes were observed in total and higher-order root-mean-square values (P<.01).

CONCLUSIONS

Hyperopic LASIK using the Esiris excimer laser for the correction of 2nd-order aberrations was safe and effective. Ocular and corneal HOAs increased significantly postoperatively.

Takagi Glare Tester CGT-1000 for Contrast Sensitivity and Glare Testing in Normal Individuals and Cataract Patients

PURPOSE

To investigate the sensitivity and repeatability of the Takagi Contrast Glare Tester CGT-1000 in normal individuals and those with cataracts.

METHODS

A prospective observational study was performed. The Takagi Contrast Glare Tester measures contrast sensitivity (CS) at 6 target sizes and 13 contrast levels (2.00 to 0.34 logCS). Testing follows a method of descending limits paradigm with a single reversal determining threshold. The CGT-1000 was administered with and without glare in 95 eyes of 61 cataract patients and 13 controls. The percentage floor (unable to see the highest contrast) and ceiling (able to see the lowest contrast) effects and correlations between CS and cataract grades were determined. The repeatability was evaluated using Bland-Altman limits of agreement and expressed as the coefficient of repeatability (COR). Factor analysis was used to test for redundancy within the 6 spatial frequencies.

RESULTS

In normal individuals, a high rate of ceiling effect varying with target size was noted--for 6.3 degrees, 4.0 degrees, 2.5 degrees, 1.6 degrees, 1.0 degrees, 0.7 degrees, ceiling effects were 68%, 58%, 18%, 11%, 4%, 2%, respectively, for no glare, and 47%, 42%, 8%, 2%, 2%, 2%, respectively, with glare. In cataract patients, floor effects were noted--3%, 0%, 3%, 7%, 19%, 62%, respectively, for no glare, and 3%, 3%, 6%, 14%, 44%, 79%, respectively, with glare. Correlations with cataract grades ranged from 0.10 to 0.61, being best for nuclear cataract. Repeatabilities expressed as COR were +/- 0.11, +/- 0.14, +/- 0.28, +/- 0.38, +/- 0.38, +/- 0.47 logCS, respectively. All spatial frequencies loaded heavily on one factor, indicating no gain in information from testing multiple target sizes.

CONCLUSIONS

Sensitivity to the presence of cataract was good, but ceiling effects in normal individuals and floor effects in cataract patients limit accuracy. Repeatability was poor, but could be improved by testing less spatial frequencies more rigorously.

Outcomes of Wavefront-Optimized Surface Ablation

PURPOSE

To compare early visual outcomes after wavefront-optimized advanced surface ablation (ASA) with those after wavefront-optimized LASIK.

DESIGN

Retrospective comparative series.

PARTICIPANTS

One hundred thirty-six eyes undergoing ASA and 136 preoperative refraction-matched eyes undergoing LASIK from June 2004 through October 2005.

METHODS

Database review of preoperative characteristics, including patient age, gender, refraction, and central corneal pachymetry; perioperative information, including type of surgery, flap thickness (for LASIK cases), ablation depth, and residual stromal bed thickness; and postoperative information, including uncorrected visual acuity (UCVA) at 1 day, 1 week, 2 weeks, and 3 months, refraction at 3 months, and complications. All ASA patients had topical mitomycin C applied intraoperatively.

MAIN OUTCOMES MEASURES

Postoperative UCVA, best spectacle-corrected visual acuity (BSCVA), spherical equivalent (SE) refraction, speed of visual recovery, and postoperative complications.

RESULTS

Surface ablation patients were younger (35.4 years vs. 39.8 years, P = 0.0002) and had thinner corneas (514 microm vs. 549 microm, P<0.0001) preoperatively. Average UCVA was significantly better after LASIK at 1 day (20/26.8 vs. 20/50.4, P<0.0001) and 2 weeks (20/24.4 vs. 20/33.3, P = 0.0002) postoperatively. However, by 3 months postoperatively, UCVA was better after ASA (20/20.8 vs. 20/22.7, P = 0.05), and 81.5% of patients achieved 20/20 or better UCVA after ASA, compared with 70.5% after LASIK (P = 0.05). More ASA eyes had postoperative UCVA that achieved or surpassed preoperative BSCVA than LASIK eyes (66% vs. 41.6%, P<0.0001). There were 53 patients who underwent bilateral simultaneous ASA. By 1 week, 87.5% had 20/40 or better UCVA in at least one eye and 62.5% had 20/40 or better UCVA in both eyes. By 2 weeks, 86.8% had 20/40 or better UCVA in one eye and 82.6% had 20/40 or better UCVA in both eyes.

CONCLUSION

Initial visual recovery is more rapid after LASIK; however, by 3 months postoperatively UCVA and SE refractions were better after ASA. Advanced surface ablation is an effective alternative to LASIK, and based on early visual recovery, bilateral simultaneous surface ablation is a reasonable alternative to sequential surgery for the majority of patients.

LASIK Using the NIDEK EC-5000 for the Correction of Hyperopic Astigmatism

PURPOSE

To assess the refractive outcomes of LASIK for the surgical correction of hyperopic astigmatism using the NIDEK EC-5000 excimer laser.

METHODS

LASIK was performed on 46 eyes from 26 patients (19 men and 7 women) for the correction of congenital hyperopic astigmatism. The NIDEK EC-5000 excimer laser and the Moria M2 microkeratome were used in all procedures. Cylindrical ablations were performed on the negative axis out to a 6-mm diameter.

RESULTS

The mean preoperative cylindrical refraction was +3.15+/-0.70 diopters (D) (range: +1.75 to +4.50 D), and the mean 24-month postoperative refraction was +1.27+/-0.78 D (range: +0.50 to +3.25 D). Vector analysis showed a 2.17+/-1.27 D reduction in the equivalent cylinder. Preoperative mean uncorrected visual acuity (UCVA) was 20/100, and 24-month postoperative UCVA was 20/30. One eye lost one line of best spectacle-corrected visual acuity at 24 months postoperatively. Complications related to the LASIK flap occurred in 2 (4.3%) eyes. Partial regression of the astigmatic effect began at 4 to 6 months but stabilized by 1 year.

CONCLUSIONS

LASIK is a safe but limited alternative for the correction of astigmatism in eyes with hyperopic astigmatism. Early regression of the astigmatic effect in the first 6 months seems to be the primary disadvantage of this technique.