Topography-guided Ablation for Treatment of Patients With Irregular Astigmatism

Aberrometric, Keratometric, and Visual Outcomes After Trans-Epithelial Topography-Guided Phototherapeutic Keratectomy for the Treatment of Irregular Corneas

Purpose

To assess the safety, aberrometric and keratometric changes, and stability of trans-epithelial topography-guided phototherapeutic keratectomy (TE-TG-PTK) with mitomycin C (MMC) using the ALLEGRO Topolyzer platform for the treatment of irregular astigmatism.

Methods

This is a retrospective case series including 57 eyes that underwent TE-TG-PTK + MMC using the ALLEGRO Topolyzer platform for the treatment of irregular astigmatism. CDVA, manifest refraction (MR), keratometry readings, and aberrometry readings were analyzed at 1, 3, 6, and 12 months.

Results

Causes of corneal irregularity included non-infectious leucoma (n=23), infectious leucoma (n=7), adenoviral keratitis (n=20), corneal haze (n=2), post-penetrant keratoplasty (PKP) (n=1), and others (n=4). Overall, 76% of the eyes (n=40) gained lines of vision; patients gained 1, and 2 or more lines of vision in 76%, and 38% of cases, respectively. Only 1 patient (2%) lost 5 lines of vision. Mean preoperative CDVA (LogMAR) was 0.37 ±0.31 and improved to 0.14 ±0.18 (p<0.001) at final follow-up (12 months). CDVA remained unchanged in 10 eyes (21%). No significant changes were observed in mean keratometry (Kmean) and keratometric astigmatism readings. Regarding aberrometry, only changes in coma proved to be significant 6 months after surgery (P<0.01). No intraoperative/postoperative complications were reported.

Conclusion

At final follow-up, significant improvements were observed in CDVA and coma. TE-TG-PTK + MMC proved to be an effective and safe procedure for the treatment of corneal irregular astigmatism due to several causes.

Correction of Myopic Astigmatism with Topography-Guided Laser In Situ Keratomileusis (TOPOLINK)

We aim to assess the feasibility of topography-guided laser in situ keratomileusis (TOPOLINK) for correcting pre-existing and surgical-induced astigmatism. A retrospective, single center cohort study was conducted. Patients with pre-existing irregular myopic astigmatism were recruited into the primary group and those with irregular myopic astigmatism following laser in situ keratomileusis (LASIK) were recruited into the enhancement group. The changes in uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), maximum astigmatism, spherical equivalent (SE) and patient satisfaction were recorded. The Chi-square test, Mann-Whitney U test and Generalized Linear Mixed Model were utilized for the analysis in the current study. A total of 18 eyes were studied in the primary group and 14 eyes were examined in the enhancement group. One year postoperatively, the UCVA, BCVA, maximum astigmatism and SE improved significantly in both the primary and the enhancement groups (all p < 0.05). The UCVA (p = 0.046) and SE (p = 0.003) were worse in the primary group preoperatively but became similar in both groups postoperatively, while the BCVA and maximum astigmatism remained identical between groups throughout the study period (all p < 0.05). In addition, the rate of high and moderate satisfaction reached 90.0% in the primary and the enhancement groups, without significant differences (p = 0.871). In conclusion, the TOPOLINK showed high predictability and will contribute to similar outcomes between primary and postoperative irregular myopic astigmatism concerning visual acuity, refractive status and subject satisfaction.

Analysis of planning strategies in primary eyes gaining a line or more of visual acuity after topography-guided laser in situ keratomileusis

PURPOSE

To analyze planning strategies for eyes that gained 1 or more lines of corrected distance visual acuity (CDVA) after topography-guided custom treatment (TCAT).

SETTING

Refractive Surgery Clinic, Cleveland Clinic, Ohio, USA.

DESIGN

Retrospective case series.

METHODS

Eyes having TCAT by the same surgeon between February 2016 and June 2017 were enrolled. The corneal shape was captured with the Wavelight Allegretto Topolyzer diagnostic device coupled with refraction, generating an ablation profile. The cylinder magnitude and axis of laser entry were decided by the surgeon based on the manifest and measured values, assisted by additional data from the Pentacam Scheimpflug tomographer and Ladarwave ocular wavefront aberrometer.

RESULTS

The study comprised 256 eyes. At 3 months, uncorrected distance visual acuity was 20/20 or better in 95.7% and 20/15 or better in 81.4%; 25.6% gained 1 or more lines of CDVA. The measured and manifest axes differed by less than 15 degrees in 59%, between 15 degrees and 30 degrees in 18%, and by more than 30 degrees in 23%. When it differed by at least 5 degrees, the measured axis was treated in 79%, 75%, and 73% of eyes, respectively. In eyes with higher measured cylinder, 75% were treated between the manifest and measured values, with 7% at full measured value. When the manifest value was greater, 60% were treated at the total measured value and 40% in between. Whole-eye aberrometry showed a small increase in coma, spherical aberration and the total root mean square (all P < .001).

CONCLUSIONS

The TCAT procedure achieved visual acuity better than the preoperative CDVA in more than 25.0% of eyes. Tomography and wavefront aberrometry assisted in the selection process to achieve optimum visual outcomes.

Incidence and Outcomes of Optical Zone Enlargement and Recentration After Previous Myopic LASIK by Topography-Guided Custom Ablation

PURPOSE

To report the incidence, visual and refractive outcomes, optical zone enlargement, and recentration using topography-guided CRS-Master TOSCA II software with the MEL 80 excimer laser (Carl Zeiss Meditec AG, Jena, Germany) after primary myopic laser refractive surgery.

METHODS

Retrospective analysis of 73 eyes (40 patients) with complaints of night vision disturbances due to either a decentration or small optical zone following a primary myopic laser refractive surgery procedure using the MEL 80 laser. Multiple ATLAS topography scans were imported into the CRS-Master software for topography-guided ablation planning. The topography-guided re-treatment procedure was performed as either a LASIK flap lift, a new LASIK flap, a side cut only, or photorefractive keratectomy. Axial curvature maps were analyzed using a fixed grid and set of concentric circles superimposed to measure the topographic optical zone diameter and centration. Follow-up was 12 months.

RESULTS

The incidence of use in the population of myopic treatments during the study period was 0.79% (73 of 9,249). The optical zone diameter was increased by 11% from a mean of 5.65 to 6.32 mm, with a maximum change of 2 mm in one case. Topographic decentration was reduced by 64% from a mean of 0.58 to 0.21 mm. There was a 44% reduction in spherical aberration, 53% reduction in coma, and 39% reduction in total higher order aberrations. A subjective improvement in night vision symptoms was reported by 93%. Regarding efficacy, 82% of eyes reached 20/20 and 100% reached 20/32 (preoperative CDVA was 20/20 or better in 90%). Regarding safety, no eyes lost two lines of CDVA and 27% gained one line. Regarding predictability, 71% of re-treatments were within ±0.50 diopters.

CONCLUSIONS

Topography-guided ablation was effective in enlarging the optical zone, recentering the optical zone, and reducing higher order aberrations. Topography-guided custom ablation appears to be an effective method for re-treatment procedures of symptomatic patients after myopic LASIK. [J Refract Surg. 2018;34(2):121-130.].

Clinical Outcomes of an Optimized Prolate Ablation Procedure for Correcting Residual Refractive Errors Following Laser Surgery

Purpose

The purpose of this study was to investigate the clinical efficacy of an optimized prolate ablation procedure for correcting residual refractive errors following laser surgery.

Methods

We analyzed 24 eyes of 15 patients who underwent an optimized prolate ablation procedure for the correction of residual refractive errors following laser in situ keratomileusis, laser-assisted subepithelial keratectomy, or photorefractive keratectomy surgeries. Preoperative ophthalmic examinations were performed, and uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction values (sphere, cylinder, and spherical equivalent), point spread function, modulation transfer function, corneal asphericity (Q value), ocular aberrations, and corneal haze measurements were obtained postoperatively at 1, 3, and 6 months.

Results

Uncorrected distance visual acuity improved and refractive errors decreased significantly at 1, 3, and 6 months postoperatively. Total coma aberration increased at 3 and 6 months postoperatively, while changes in all other aberrations were not statistically significant. Similarly, no significant changes in point spread function were detected, but modulation transfer function increased significantly at the postoperative time points measured.

Conclusions

The optimized prolate ablation procedure was effective in terms of improving visual acuity and objective visual performance for the correction of persistent refractive errors following laser surgery.

Laser Vision Correction in Treating Myopia

Myopia is a generally benign refractive error with an increasing prevalence worldwide. It can be corrected temporarily with glasses and contact lenses and permanently with laser vision correction. The 2 main procedures currently being performed for myopia correction are photorefractive keratectomy and laser-assisted in situ keratomileusis. Each technique has its advantages, but they appear to yield similar visual outcomes 1 year after surgery. Laser vision correction for myopia was considered a paradigm shift because healthy eyes could now undergo a surgical procedure to permanently and safely correct the error by altering the center of the cornea, which was previously off limits because of the potential for loss of transparency. Customized ablation using wavefront aberrometry and its optimized profiles were created to correct higher-order aberrations and give more vision quality to patients. Topography-guided ablation, initially used for complex retreatments, shows potential to make vision even better than glasses and contact lenses in a recent study on previously untreated eyes. One major concern is to identify corneas that are at risk of developing ectasia after the procedure. Topographic and tomographic screening indices have been implemented clinically, but there is still much to learn about corneal biomechanics. A more recently developed procedure for myopia correction is small-incision lenticule extraction, in which a lenticule is created in the cornea's stroma with a femtosecond laser and extracted through a small corneal incision. Long-term outcomes and new complication risks need to be better understood as this procedure develops.

Multifocal intraocular lenses: relative indications and contraindications for implantation

This article presents an extensive overview of best clinical practice pertaining to selection and use of multifocal intraocular lenses (IOLs) currently available in the United States. Relevant preoperative diagnostic evaluations, patient selection criteria, counseling, and managing expectations are reviewed, as well as how to approach patients with underlying ocular intricacies or challenges and best practices for intraoperative challenges during planned implantation of a multifocal IOL. Managing the unhappy multifocal IOL patient if implantation has been performed is also addressed.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Customized aspheric treatment zone ablation to treat irregular corneas after corneal refractive surgery

PURPOSE

To describe the retreatment of highly aberrated corneas due to previous keratorefractive surgery using topography-guided aspheric treatments.

METHODS

Eight eyes (five patients) with reduced mesopic visual quality due to previous keratomileusis, excimer laser surgery, or radial keratotomy underwent retreatment with the customized aspheric treatment zone (CATz) algorithm with the CXIII excimer laser (NIDEK Co Ltd) to correct corneal wavefront aberrations. Before CATz treatments, all patients were satisfied with their preoperative photopic vision (all 20/30 or better uncorrected) yet were dissatisfied with their vision at night. All eyes had >20 microm (range: 20 to 33 microm) of corneal irregularity before CATz retreatment. All eyes had a flap cut or flap lift procedure for CATz retreatment.

RESULTS

One year after treatment with CATz, no eyes lost best spectacle-corrected visual acuity (BSCVA); all eyes had BSCVA of 20/30 or better. Mean modulation transfer function increased by 13% by the end of the first postoperative year. A 0.45-microm decrease was noted in coma 1 year postoperatively.

CONCLUSIONS

The CATz algorithm is effective in the treatment of severe corneal irregularities due to previous corneal surgery.

Combined corneal topography and corneal wavefront data in the treatment of corneal irregularity and refractive error in LASIK or PRK using the Carl Zeiss Meditec MEL 80 and CRS-Master

PURPOSE

To assess the efficacy, safety, and accuracy of TOSCA II (Topography Supported Custom Ablation) treatments for the correction of high corneal aberrations and refractive error following previous ocular surgery.

METHODS

Forty-eight eyes of 32 patients were included for study. Indications for TOSCA II treatment included small optical zone, decentered ablation, subjective visually significant higher order aberrations, and irregularly irregular astigmatism induced by LASIK, photorefractive keratectomy, radial keratotomy, conductive keratoplasty, cataract surgery, and deep lamellar keratoplasty. An ablation profile based on corneal topography data and corneal wavefront and manifest refraction was created using the CRS-Master software (Carl Zeiss Meditec) to treat corneal irregularity and refractive error simultaneously. Postoperative assessments were performed at 1 week and 1, 2, 3, 6, and 12 months.

RESULTS

Mean attempted spherical equivalent refraction (SE) was -1.12 +/- 1.97 diopters (D) (range: +1.13 to -10.50 D). Mean attempted cylinder correction was 1.34 +/- 1.65 D (range: 0.00 to 7.75 D). Median age was 38 years (range: 19 to 68 years). Median follow-up was 9.4 months. Accuracy: mean deviation from the intended SE correction was -0.19 +/- 0.94 D, 60% of eyes were within +/- 0.50 D and 77% of eyes were within +/- 1.00 D of the intended SE. Cylinder: the correction ratio was 1.49 +/- 0.85 and the error ratio was 0.87 +/- 0.69.

EFFICACY

56% of eyes achieved uncorrected visual acuity of 20/20 or better and 88% achieved 20/40 or better.

SAFETY

34% of eyes gained one or more lines of best spectacle-corrected visual acuity, 15% lost one line, and no eye lost two or more lines. Contrast sensitivity: for the subset of eyes with below normal contrast sensitivity preoperatively, there was a statistically significant improvement in contrast sensitivity at 3 cycles per degree (cpd), 6 cpd, and 12 cpd (P < .05). Stability: the average change in refraction between 3 months and 1year was +0.38 +/- 0.30 D. Higher order aberrations: the average higher order root-mean-square decreased by 21% and the average spherical aberration decreased by 41%.

CONCLUSIONS

The MEL 80 CRS-Master TOSCA II software appears to be an effective treatment for decentrations, optical zone enlargement, and reduction of higher order aberrations. The refractive outcome was satisfactory after one treatment.