Asphericity analysis using corneal wavefront and topographic meridional fits

Comparison of Refractive and Visual Outcomes after Transepithelial Photorefractive Keratectomy (TransPRK) in Low versus Moderate Myopia

Is it possible to obtain good results in myopia of 2 or fewer diopters (D) with transepithelial photorefractive keratectomy (TransPRK) changing the optical zone and epithelium thickness? We retrospectively analyzed two groups of 296 eyes with a minimum follow-up of 4 months. Group A had 2 or less D, treated with an optical zone (OZ) 0.2 mm bigger than recommended, and a central epithelium thickness of 60 microns, and group B had 2 D to 5 D, with the recommended optical zone, and a 55-micron epithelium ablation at the center. The outcomes were not different between the two myopic ranges; the postop uncorrected distance visual acuity was 20/20 ± 4 in both groups (p = 0.2), which was −0.3 ± 0.8 lines worse than the preoperative corrected distance visual acuity in both groups (p = 0.5). The safety of the treatments resulted in a change of 0.0 ± 0.7 lines in the low myopia group, versus a gain of +0.1 ± 0.8 lines in the moderate myopia group (p = 0.1). The deviation from the intended target was −0.04 ± 0.33 D in the low myopia group and +0.07 ± 0.32 D in the moderate myopia group (p < 0.0001); the postoperative spherical equivalent was 0.00 ± 0.33 D in the low myopia group and +0.10 ± 0.31 D in the moderate myopia group (p < 0.0001). The postop refractive astigmatism was 0.32 ± 0.16 D in both groups (p = 0.5). In conclusion, the refractive and visual outcomes after TransPRK are comparable in low myopia changing the optical zone and epithelium thickness versus moderate myopia with standard optical zone and epithelium thickness.

Myopia correction with transepithelial photorefractive keratectomy versus femtosecond-assisted laser in situ keratomileusis: One-year case-matched analysis

PURPOSE

To compare the postoperative clinical outcomes of single-step transepithelial photorefractive keratectomy (PRK) and femtosecond-assisted laser in situ keratomileusis (LASIK).

SETTING

Bergman Clinics, Utrecht, the Netherlands.

DESIGN

Retrospective case series.

METHODS

The eyes of consecutive patients who had transepithelial PRK were retrospectively compared with the same number of case-matched eyes (based on the preoperative refractive components) treated with femtosecond-assisted LASIK. The clinical outcomes evaluated were predictability, refractive outcomes, and visual acuity. The Student t test and chi-square test were used for statistical analysis.

RESULTS

The study compared 98 patients (196 eyes) who had transepithelial PRK with the outcomes in 196 case-matched eyes that had femtosecond-assisted LASIK. All patients completed the 1-year follow-up. At 1 year, 130 eyes (66%) in the transepithelial PRK group and 91 eyes (46%) in the femtosecond-assisted LASIK group achieved an uncorrected distance visual acuity of -0.1 logMAR or better (P < .005), 4 eyes (2%) in the transepithelial PRK and 2 eyes (1%) in the femtosecond-assisted LASIK group lost 2 lines of corrected distance visual acuity (P = .04), and 163 eyes (83%) in the transepithelial PRK and 167 eyes (85%) in the femtosecond-assisted LASIK group were within ±0.50 diopter (D) of emmetropia. The postoperative mean spherical equivalent was +0.11 D ± 0.56 (SD) for transepithelial PRK and -0.09 ± 0.46 D for femtosecond-assisted LASIK (P < .0001).

CONCLUSIONS

Transepithelial PRK outcomes 1 year postoperatively were equivalent to those of femtosecond-assisted LASIK. Transepithelial PRK was efficacious and safe; however, the procedure had a longer recovery time than the femtosecond-assisted LASIK.

FINANCIAL DISCLOSURE

Mr. Ewering and Dr. Arba-Mosquera are employees of Schwind eye-tech-solutions GmbH and Co. KG. Dr. Luger has no financial or proprietary interest in any material or method mentioned.

Corneal-Wavefront guided transepithelial photorefractive keratectomy after corneal collagen cross linking in keratoconus

PURPOSE

To evaluate the efficacy and safety of Corneal-Wavefront guided transepithelial photorefractive keratectomy (TransPRK) after corneal collagen cross linking (CXL) in keratoconic patients.

METHODS

In this retrospective, non-comparative, consecutive case series, 39 keratoconic eyes underwent Corneal-Wavefront guided TransPRK for the correction of aberrations at least 4 months after conventional CXL at SEKAL Rovigo Microsurgery Centre, Rovigo, Italy. Two eyes (5%) underwent a secondary laser retreatment for the improvement of post-operative visual acuity and were not included in this retrospective analysis. The mean age of the patients was 35±12 years (19-64 years) at the time of the surgery. Keratron-Scout (Optikon) topographer was used for diagnostic tests and a flying-spot laser (AMARIS; SCHWIND eye-tech-solutions) was used for the refractive surgery. Complete ophthalmic examinations were performed before and after the surgery (4-36 months postoperatively with a mean follow up time of 10±8 months).

RESULTS

Preoperatively, eyes showed irregular astigmatism up to 8D. At last postoperative follow-up, 21 eyes (57%) had UDVA better than 20/40, and six eyes (16%) had UDVA of 20/20. Twenty-three eyes (62%) were within 1.50D of attempted correction in spherical equivalent (mean deviation from target was +1.09±2.36D, range -2.50 to +7.38D). No eye lost 2 Snellen lines of CDVA, and 15 eyes (41%) had an increase of more than 2 lines.

CONCLUSIONS

Corneal-Wavefront guided transepithelial PRK ablation profiles after conventional CXL yields to good visual, optical, and refractive results. These treatments are safe and efficacious for the correction of refracto-therapeutic problems in keratoconic patients.

Analysis of seasonal changes in residual refraction 1-year after corneal laser refractive surgery: a retrospective study

PURPOSE

To analyze the effect of seasonal changes in residual refraction 1-year after corneal refractive surgery using the SCHWIND AMARIS laser system.

METHODS

5740 consecutive treatments have been retrospectively reviewed. For all eyes, aspheric treatments were planned with the Custom Ablation Manager software and the ablations were performed with the SCHWIND AMARIS system (SCHWIND eye-tech-solutions). Seasonal outcomes were evaluated in terms of residual refraction stratified per treatment month, as well as stratified per year season. Student's T test comparing stratified values with global ones was used for the statistical analysis.

RESULTS

Treatments performed in April, June, August, September, and October showed relative undercorrections of the spherical equivalent (SE) (-0.09D), whereas treatments performed in January, February, and March showed relative overcorrections of the SE (+0.13D). Similarly, treatments performed in spring and summer showed relative undercorrections of the SE (-0.04D), whereas treatments performed in winter showed relative overcorrections of the SE (+0.10D).

CONCLUSIONS

Seasonal differences in refractive outcomes were observed among a large scale population. The effect of these environmental variables on refractive outcomes warrants further evaluation.

Influence of stromal refractive index and hydration on corneal laser refractive surgery

PURPOSE

To evaluate the influence of the stromal refractive index and hydration on postoperative outcomes in eyes that had corneal laser refractive surgery using the Amaris laser system.

SETTING

Augenzentrum Recklinghausen, Recklinghausen, Germany.

DESIGN

Comparative case series.

METHODS

At the 6-month follow-up, right eyes were retrospectively analyzed. The effect of the stromal refractive index and hydration on refractive outcomes was assessed using univariate linear and multilinear correlations.

RESULTS

Sixty eyes were analyzed. Univariate linear analyses showed that the stromal refractive index and hydration were correlated with the thickness of the preoperative exposed stroma and was statistically different for laser in situ keratomileusis and laser-assisted subepithelial keratectomy treatments. Univariate multilinear analyses showed that the spherical equivalent (SE) was correlated with the attempted SE and stromal refractive index (or hydration). Analyses suggest overcorrections for higher stromal refractive index values and for lower hydration values.

CONCLUSIONS

The stromal refractive index and hydration affected postoperative outcomes in a subtle, yet significant manner. An adjustment toward greater attempted correction in highly hydrated corneas and less intended correction in low hydrated corneas might help optimize refractive outcomes.

FINANCIAL DISCLOSURE

Mr. Magnago and Dr. Arba-Mosquera are employees of and Dr. Diego de Ortueta is a consultant to Schwind eye-tech-solutions GmbH & Co. KG. Mr. Rüden has no financial or proprietary interest in any material or method mentioned.

One-year experience in presbyopia correction with biaspheric multifocal central presbyopia laser in situ keratomileusis

PURPOSE

To analyze simultaneous vision (distance and near) 1-year after biaspheric multifocal central presbyLASIK treatments for hyperopia and myopia with or without astigmatism.

METHODS

Patients were treated to correct distance ametropias and alleviating presbyopic symptoms simultaneously. All patients have been treated in Presby aberration-free mode using FemtoLASIK for Sphere from -7.00 to +3.25 diopters (D), astigmatism up to 3.00 D, and addition up to +2.75 D. No eye had previous corneal refractive surgery. Preoperative corneal curvature ranged between 40 and 48 D, with pachymetry thicker than 500 μm. Preoperative corrected distance visual acuity was 0.1 logarithm of the minimum angle of resolution (logMAR) or better, with near vision of 0.2 logRAD or better with addition up to +2.50 D.

RESULTS

Sixty-six eyes treated bilaterally using PresbyMAX software were reviewed. For 31 patients (94%), 1-year follow-up was completed. At 1 year, 70% of patients achieved uncorrected distance visual acuity 0.1 logMAR or better, 84% patients obtained uncorrected near visual acuity 0.1 logRAD or better, and 83% of eyes were within 0.75 D of defocus. Postoperative mean spherical equivalent refraction was -0.47 ± 0.44 D. Stability was achieved from the 6-week follow-up. Eighty-five percent of patients achieved simultaneously uncorrected distance visual acuity 0.2 logMAR or better and uncorrected near visual acuity 0.2 logRAD or better.

CONCLUSION

Patient selection and expectation management is essential to achieve patient satisfaction. Even though optically the results are predictable and good, some patients find it difficult to adapt to the compromise and others are dissatisfied by the minor loss of distance visual acuity. Certain individuals are best suited for PresbyMAX. A test with multifocal contact lenses or trial frames that creates slightly defocused images can be used to simulate postoperative visual impressions and verify patient acceptance.

Influence of patient age on high myopic correction in corneal laser refractive surgery

PURPOSE

To evaluate the influence of patient age on the postoperative outcomes in eyes with myopia higher than 5.00 diopters (D) that had laser in situ keratomileusis using the Schwind Amaris laser system.

SETTING

Private practice, Utrecht, The Netherlands.

DESIGN

Case series.

METHODS

At the 1-year follow-up, right eyes with preoperative myopia higher than 5.00 D were analyzed. The effect of the patient's age on postoperative status was assessed using univariate linear and multilinear correlations.

RESULTS

The study analyzed 612 eyes. Univariate linear analyses showed that residual refraction was correlated with patient age. Univariate multilinear analyses showed that spherical equivalent (SE) was correlated with the attempted SE and patient age, whereas cylinder was correlated with attempted cylinder only. Analyses suggested overcorrections and higher residual astigmatism values for older patients.

CONCLUSIONS

Patient age affected postoperative outcomes in a subtle, yet significant manner. An age-dependent adjustment toward greater attempted correction in younger patients and less intended correction in older patients may help optimize refractive outcomes.

FINANCIAL DISCLOSURE

Drs. Ewering and Arba-Mosquera are employees of Schwind eye-tech-solutions GmbH. Dr. Luger has no financial or proprietary interest in any material or method mentioned.

Uncorrected binocular performance after biaspheric ablation profile for presbyopic corneal treatment using AMARIS with the PresbyMAX module

PURPOSE

To analyze the uncorrected binocular performance after biaspheric multifocal central presbyopic laser in situ keratomileusis treatments.

DESIGN

Retrospective, interventional case series.

METHODS

setting. Private clinical practice. patient or study population. Three hundred fifty-eight presbyopic patients (43% males, 82 myopic), bilaterally treated, suitable for laser in situ keratomileusis, with monocular corrected distance visual acuity of 20/32 or better. intervention or observation procedure(s). PresbyMAX (Schwind Eye-Tech-Solutions GmbH and Co) biaspheric multifocal ablation. main outcome measures. Binocular uncorrected distance visual acuity (UDVA) and near visual acuity (UNVA) after surgery and their changes compared with corrected distance visual acuity and corrected near visual acuity before surgery.

RESULTS

At 6 months, 76% of patients achieved a UDVA of 0.1 logarithm of the minimal angle of resolution (logMAR; Snellen equivalent, 20/25) or better, 91% of patients obtained a UNVA of 0.1 logarithmic of the reading acuity determination (logRAD) (p3) or better, and 99% of patients were within 1 diopter of defocus. Postoperative mean spherical equivalent was -0.17 ± 0.34 diopter. Ninety-six percent of patients achieved a UDVA of 0.2 logMAR (Snellen equivalent, 20/32) or better and a UNVA of 0.2 logRAD (p4) or better. Mean binocular corrected distance visual acuity degraded from 0.00 ± 0.01 logMAR (Snellen equivalent, 20/20) to a UDVA of 0.09 ± 0.07 logMAR (Snellen equivalent, 20/25). Mean binocular corrected near visual acuity degraded from 0.02 ± 0.01 logRAD (p2) to a UNVA of 0.07 ± 0.07 logRAD (p2).

CONCLUSIONS

Although optically the results are predictable, approximately 17% of the patients did not obtain objectively successful outcomes. In presbyopic patients without symptomatic cataracts, but with refractive errors, the PresbyMAX will decrease the presbyopic symptoms and correct far distance refraction in the same treatment, offering spectacle-free vision in daily life in most of the patients. Further investigation is necessary to evaluate the overall benefit of this procedure.