Correlation of visual outcome and patient satisfaction with preoperative keratometry after hyperopic laser in situ keratomileusis

Hyperopic LASIK and postoperative corneal steepness: revisiting the 49-diopter limit

PURPOSE

To compare corrected distance visual acuity (CDVA) outcomes of hyperopic laser in situ keratomileusis (LASIK) with a postoperative corneal steepness above vs below 49 diopters (D).

SETTING

Care-Vision Laser Centers, Tel-Aviv, Israel.

DESIGN

Retrospective study.

METHODS

This study included consecutive patients who underwent hyperopic LASIK between January 2013 and December 2019. Hyperopic patients were divided into 2 groups based on postoperative corneal steepness with steep corneas defined >49.0 D and the control group ≤49.0 D. Adjustments were performed to account for differences in baseline and intraoperative parameters.

RESULTS

Overall, 1703 eyes of 1703 patients were included. Mean age was 48.3 ± 10.0 years, and 45.3% were male. Preoperatively, the steep group (2.4%, n = 41/1703) had steeper mean (44.6 D vs 43.1 D, P < .001) and steep (45.1 D vs 43.5 D, P < .001) keratometry, worse logMAR CDVA (0.07 vs 0.04, P = .02), and higher sphere (4.9 D vs 2.9 D, P < .001). Intraoperatively, they had a higher spherical treatment (4.6 D vs 2.8 D, P < .001). After hyperopic LASIK, the steep group had worse logMAR CDVA (0.10 vs 0.06, P = .01). However, after accounting for differences in baseline and spherical treatment, no significant differences were found in postoperative logMAR CDVA (0.06 vs 0.06, P = .99). The factors that remained associated with worse postoperative CDVA were higher spherical treatment (0.01 logMAR per 1 D, P < .001) and preoperative CDVA (0.60 logMAR per 1.00 logMAR, P < .001).

CONCLUSIONS

Postoperative corneal steepness greater than 49 D is not associated with worse visual outcomes after hyperopic LASIK. However, lower preoperative visual potential and higher spherical treatment applied are associated with worse outcomes. The 49 D cutoff should be revisited.

Hyperopic laser keratorefractive surgery: Do steep corneas have worse outcomes?

PURPOSE

To report the visual and refractive outcomes of hyperopic patients undergoing laser keratorefractive surgery in preoperatively steep corneas versus a matched control group.

METHODS

Retrospective cohort study. All patients underwent photorefractive keratectomy (PRK) or laser-assisted in situ keratomileusis (LASIK) at Care-Vision Laser Centers, Tel-Aviv, Israel, between 1/2000 and 11/2016. Patients were divided into two groups: steep corneas (mean keratometry ≥ 44.00 D) and control group (mean keratometry < 44.00 D). The two study groups were matched by age, gender, sphere and cylinder. Only the right eye of each patient was included. Outcomes included postoperative uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (CDVA), safety and efficacy indexes, refractive outcomes and retreatment rates.

RESULTS

Five hundred and two patients were included. Both groups were similar in demographic data, visual acuity and refraction. Postoperatively, the steep corneas group had a significantly higher mean keratometry as compared to the control group (46.52 ± 1.43 D vs 44.58 ± 1.68 D, p < 0.001), K_min (46.04 ± 1.50 D vs 44.12 ± 1.76 D, p < 0.001) and K_max (46.99 ± 1.51 D vs 45.03 ± 1.77 D, p < 0.001). Both groups had similar postoperative UDVA and CDVA and achieved a similar final sphere (0.64 ± 0.19 vs 0.54 ± 1.19, p = 0.44) and cylinder (- 0.89 ± 0.59 vs - 0.86 ± 0.72, p = 0.67). Both groups had a similar efficacy index (0.92 ± 0.22 vs 0.90 ± 0.25, p = 0.33) and similar retreatment rates (4.2% vs 3.5%, p = 0.74). None of the patients in either group underwent more than one retreatment throughout the follow-up period.

CONCLUSIONS

Hyperopic patients with steep corneas undergoing laser keratorefractive surgery can achieve adequate visual and refractive outcomes, similar to control group.

Six-Month Outcomes After High Hyperopia Correction Using Laser-Assisted In Situ Keratomileusis With a Large Ablation Zone

PURPOSE

To evaluate refractive and visual outcomes of laser-assisted in situ keratomileusis (LASIK) to treat high hyperopia using an aberration-neutral profile and large ablation zone.

METHODS

This was a retrospective, consecutive observational case series at Helios Ophtalmologie, St. Jean-de-Luz, France. One hundred forty-six consecutive eyes of 77 patients who underwent LASIK with mechanical microkeratome to correct hyperopia with correction in the maximum hyperopic meridian strictly higher than +5 D (mean + 6.6 ± 1.0 D) were included. Procedures were performed with an Amaris 750S excimer laser (Schwind eye-tech-solutions GmbH, Kleinostheim, Germany) using an aberration-neutral profile, a 6.7 ± 0.1 mm optical zone, and a 9.2 ± 0.1 mm total ablation zone. Refractive results, predictability, safety, and efficacy were evaluated at 6 months postoperatively.

RESULTS

At 6 months postsurgery, the mean manifest refraction spherical equivalent was -0.06 ± 0.83 D and the mean cylinder was 0.42 ± 0.35 D. Sixty-six percent of eyes were within ±0.50 D of the attempted spherical equivalent correction. Six months postoperatively, 60% of eyes achieved an uncorrected distance visual acuity of 20/20 or better. Ten percent of eyes lost 1 line of corrected distance visual acuity and 4% gained a line. No eyes lost more than 2 Snellen lines of corrected distance visual acuity at any follow-up.

CONCLUSIONS

High hyperopia correction with LASIK using an aberration-neutral profile and large ablation zone provides good efficacy, safety, predictability, and visual outcomes.

Correlation between refractive state, corneal thickness, and keratometry in ametropic patients

PURPOSE

To analyze the correlation between age, gender, refractive error, keratometry, and corneal thickness in a large group of subjects.

METHODS

This study is a retrospective analysis of patients who underwent refractive surgery between January 2000 and February 2015 at Care Vision Refractive Clinic, Tel Aviv, Israel. Patient demographics, subjective refraction, pachymetry, and average keratometry were collected.

RESULTS

Overall, 51,113 eyes of patients averaging 28.8 ± 9.3 years of which 53.9% were males were included. Average keratometry, spherical equivalent and cylindrical error differed significantly between male and female subjects (p < 0.001), while pachymetry did not (p = 0.332). In myopic eyes, correlations between age, pachymetry, average keratometry, spherical equivalent, and cylindrical error were all statistically significant except for the correlation between age and either pachymetry (p = 0.462) or spherical equivalent (p = 0.016). All correlations found were negligible or small (|r|= 0.003 to 0.141). In hyperopic eyes, correlations between age, pachymetry, average keratometry, spherical equivalent, and cylindrical error were all statistically significant except for the correlation between average keratometry and either pachymetry or cylindrical error (p = 0.344 or p = 0.274, respectively). All correlations found were negligible or small, except for a moderate correlation found between age and cylindrical error (r = 0.365).

CONCLUSION

Refractive state, pachymetry, and keratometry of refractive surgery candidates are mostly weakly correlated.

Patient satisfaction and self-reported dry eye symptoms in hyperopic patients treated with femtosecond laser in situ keratomileusis

Purpose

To study self-reported patient satisfaction and dry eye symptoms in hyperopic correction with femtosecond laser-assisted in situ keratomileusis (FS-LASIK).

Patients and methods

Ninety-eight eyes (53 patients) were treated with FS-LASIK for hyperopia. Patients’ self-reported dry eye symptoms and satisfaction with near and far vision were graded on the visual analog scale (VAS) preoperatively and 1 month postoperatively.

Results

Ninety-one percent of the eyes with the plano target (54 eyes) achieved an uncorrected distance visual acuity of 20/20 or better. Predictability, defined as spherical equivalent refraction within ±0.5 D of target, was 88% of all eyes. None of the eyes lost two or more Snellen lines of corrected distance visual acuity. There was no significant change in the self-reported dry eye sensation (VAS score from 2.7±2.0 to 2.8±2.0; P=0.66). In 44 monovision patients, satisfaction with both far vision (from 71.2±19.8 to 89.2±8.7; P<0.0001) and near vision (from 51.7±26.2 to 89.3±13.2; P<0.0001) increased significantly. In nine emmetropic patients, satisfaction with neither far vision nor near vision was significantly improved, although there was a clear tendency (from 73.7±23.7 to 86.9±15.3; P=0.22, and from 58.9±29.1 to 81.6±17.4; P=0.11, respectively). In the monovision patient group, far vision satisfaction decreased when dry eye symptoms increased. Monovision patients, as predicted, were more satisfied with their near vision, when postoperative spherical equivalent from target was on the myopic side.

Conclusion

FS-LASIK correction of hyperopia significantly improved patient satisfaction with both near and far vision in monovision patients. Hyperopic patients had no significant changes in postoperative dry eye symptoms compared to preoperative values.

Induced De Novo Astigmatism After Hyperopic LASIK Versus Myopic LASIK Surgery in Nonastigmatic Eyes

PURPOSE

To compare the astigmatism induced surgically (SIA) by spherical hyperopic laser in situ keratomileusis (H-LASIK) versus myopic laser in situ keratomileusis (M-LASIK) in nonastigmatic eyes.

METHODS

A retrospective study of patients who underwent LASIK surgery between 2005 and 2014 at the Care-Vision Laser Center, Israel. We calculated the mean absolute SIA and performed risk factor analysis for induced astigmatism. Differences between H-LASIK and M-LASIK were analyzed.

RESULTS

Eyes of 3877 patients who underwent M-LASIK and of 549 patients who underwent H-LASIK were nonastigmatic preoperatively and received a nonastigmatic treatment. Three months after surgery, hyperopic treatment induced more SIA (0.49 ± 0.48 D) than did myopic treatment (0.36 ± 0.4 D) (P < 0.001). In the H-LASIK group, the risk factors for induced astigmatism of >0.5 D were a higher preoperative refractive error (P = 0.003) and larger optical zone (7 vs. 6 mm). In the M-LASIK group, eyes with SIA >0.5 D tended to have steeper corneas preoperatively (43.8 ± 1.5 vs. 43.6 ± 1.4 D; P = 0.001), a higher spherical equivalent (-3.43 ± 1.53 Vs. -3.07 ± 1.45 P < 0.001), and smaller treatment zones (6 vs. 7 mm). In H-LASIK, the mean induced astigmatic axis was at 74.6 degrees.

CONCLUSIONS

There was a consistent trend toward more SIA in H-LASIK and in higher refractive error correction. In H-LASIK larger optical zones induce more SIA and in M-LASIK smaller ones caused it.

Laser in Situ Keratomileusis for High Hyperopia with Corneal Vertex Centration and Asymmetric Offset

Purpose

To investigate refractive outcomes and induction of corneal higher order aberrations (HOA) in eyes that underwent laser-assisted in situ keratomileusis (LASIK) for high hyperopia correction using an aberration neutral profile with corneal vertex centration and asymmetric offset.

Methods

A total of 24 consecutive patients (38 eyes) who underwent LASIK by one surgeon using AMARIS 750S excimer laser and a Carriazo-Pendular microkeratome for flap creation were retrospectively analyzed. Eyes targeted for plano and with correction in the maximum hyperopic meridian strictly higher than +4D were included in the retrospective analysis. Patients were reviewed at 1, 3, and 6 months postoperatively. Postoperative monocular corrected distance visual acuity (CDVA) and uncorrected distance visual acuity (UDVA), manifest refraction, and corneal wavefront aberrations were compared with respective preoperative metrics.

Results

Mean preoperative spherical equivalent and refractive astigmatism was +4.07 ± 0.90 D and 1.37 ± 1.26 D, respectively, reducing to +0.28 ± 0.58D (p<0.0001) and 0.49 ± 0.47 D (p = 0.0001) at the last postoperative visit. Six months postoperatively, 78% of eyes achieved a UDVA of 20/25 or better. No eye lost more than 2 Snellen lines of CDVA at any follow-up. There was a statistically significant induction of vertical trefoil (+0.104 ± 0.299 µm, p<0.05), vertical coma (-0.181 ± 0.463 µm, p<0.01), horizontal coma (+0.198 ± 0.663 µm, p<0.05), spherical aberration (-0.324 ± 0.281 µm, p<0.0001), secondary vertical trefoil (+0.018 ± 0.044 µm, p<0.01), and secondary horizontal coma (+0.026 ± 0.083 µm, p<0.05)

Conclusions

Laser-assisted in situ keratomileusis for high hyperopia using corneal vertex centration with asymmetric offset results in significant improvement in refraction and visual acuity although affected by significant induction of some higher order aberrations.

Effect of Flat Cornea on Visual Outcome after LASIK

Purpose. To evaluate the effect of preoperative and postoperative keratometry on the refractive outcome after laser in situ keratomileusis (LASIK) for moderate and high myopia. Methods. Records of 812 eyes (420 patients) with myopia ≥−6 D who had LASIK at Sohag Laser Center, Egypt, from January 2010 to November 2013, were retrospectively analyzed. Main outcome measures were postoperative corrected distance visual acuity (CDVA), postoperative spherical equivalence, and postoperative Q factor. Results. LASIK was performed in 812 eyes (mean age 21.8 ± 5.2 years). Patients were grouped according to the degree of preoperative myopia into three groups: Group 1, −6 D to −7.9 D; Group 2, −8 to −9.9 D; and Group 3, −10 to −12 D. The refractive outcome among the different myopia groups was stratified by pre- and postoperative keratometry. A trend toward greater undercorrection was noted in eyes with preoperative keratometry <43.5 D compared with those with steeper keratometry >46 D in all myopia groups. The undercorrection was also noted in postoperative keratometry groups <35 D. Conclusions. Preoperative and postoperative keratometry appeared to influence the refractive outcome especially in high myopic eyes.

Screening of refractive surgery candidates for LASIK and PRK

PURPOSE

The aim of this study was to evaluate exclusion criteria in screening patients for refractive surgery.

METHODS

Patients screened for initial refractive surgery by a single surgeon at the Cole Eye Institute (Cleveland Clinic) between 2007 and 2012 were reviewed. Exclusion criteria for patients who were not offered refractive surgery based on history and/or examination parameters were analyzed.

RESULTS

A total of 1067 refractive candidates were enrolled in the study. Five hundred nineteen (48.6%) were male and 548 (51.4%) were female with a mean age of 39 ± 12 (range, 17-78) years. Refractive surgery was performed in 657 (61.6%) patients, and photorefractive keratectomy was considered the best option for 106 (9.9%) patients. Four hundred ten (38.4%) of all screened patients did not have refractive surgery, and 134 of these patients (12.6%) were considered to have contraindications for laser in situ keratomileusis and photorefractive keratectomy. Among the excluded patients, 69 (51.5%) were male and 65 (48.5%) were female with a mean age of 40 ± 14 (range, 18-78) years. Abnormal corneal topography (34.3%) and low or insufficient corneal thickness (23.1%) were the most common reasons for exclusion. High myopia (10.5%) and (insipient or definite) cataract (9.7%) were also common reasons for exclusion. Other common factors for exclusion were high hyperopia (3.7%), need to wear reading glasses after surgery (3.7%), and severe dry eye unresponsive to treatment (3.7%).

CONCLUSIONS

Abnormal corneal topography and low, or insufficient, corneal thickness remain the most common exclusion factors for corneal refractive surgery. Factors such as cataract, too high of correction, and severe dry eye are also common reasons for exclusion of patients.

The effect of preoperative keratometry on visual outcomes after moderate myopic LASIK

Purpose

To evaluate visual outcomes in moderately myopic eyes with flat and steep corneas (preoperatively) that have been treated with laser-assisted in situ keratomileusis (LASIK).

Patients and methods

Records of ninety-six eyes with average preoperative keratometry (K) values between 39.9 and 42.0 diopters (D) (flat) were matched with 103 eyes with preoperative K values between 46.0 and 47.2 D (steep) that underwent LASIK between March 2007 and March 2010 for moderate myopia, and were retrospectively reviewed. The primary outcome measures used to determine the effect of preoperative keratometry on visual prognosis were refraction, visual acuity, change in keratometry (ΔK), and change in spherical equivalent (ΔSE), measured at 1, 3, 6, and 12 months postoperatively.

Results

Significant differences were found at 6 months postoperatively between the flat group and steep group in SE (P = 0.029), sphere (P = 0.018), ΔK (P = 0.002), percentage of eyes achieving SE of −0.25 to + 0.25 D (P = 0.0125), −0.26 to −0.50 D (P = 0.003), −0.51 to −1.00 D (P = 0.044), and the percentage of eyes achieving uncorrected distance visual acuity of 20/15 or better (P = 0.0006).

Conclusion

Moderately myopic eyes with flatter corneas preoperatively have better visual prognosis following LASIK compared with moderately myopic eyes with steeper corneas.

An evidence-based approach to patient selection for laser vision correction

PURPOSE

To describe the process used by Optical Express, a large corporate refractive surgery provider, to develop evidence-based patient selection guidelines for laser vision correction.

METHODS

The evaluation of patient selection criteria for laser vision correction is part of a larger corporate process of continuous quality improvement and clinical due diligence. The procedures used to evaluate patient selection criteria are described in detail and the benefits of this process are explained. The criterion review process involves the company's International Medical Advisory Board (IMAB) and includes an evaluation of the published literature and analyses generated from the large Optical Express clinical outcomes database. This article offers a case study in which the IMAB used the criterion review process to examine the upper limit for estimated postoperative keratometry in hyperopic laser vision correction.

RESULTS

The patient selection criteria undergo continuous scrutiny and are modified whenever medical evidence indicates that change is appropriate.

CONCLUSIONS

Using an established protocol for reviewing patient selection criteria, Optical Express continuously measures its patient selection criteria against both external (published) and internal data sources. This process ensures that decisions about patients' suitability for surgery are based on the best-available current medical evidence.

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.