SPS-215 Refractive Procedure Outcomes: PRK, LVC, LASIK | ASCRS
2020 ASCRS Virtual Annual Meeting

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Papers in this Session
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Topography-Guided Photorefractive Keratectomy and Collagen Cross-Linking for Post-LASIK Ectasia. (No Audio)
Authors
Edward E. Manche, MD
Gabriel S. Valerio, MD, ABO

Purpose
To prospectively evaluate outcomes of topography-guided LASIK in the treatment of myopia and compound myopic astigmatism. Outcome measures include high contrast snellen acuity, low contrast snellen acuity (5 and 25%), safety, predictability, efficacy, HOA analysis, changes in epithelial thickness maps using anterior segment OCT (AS-OCT).

Methods
Fifty-six eyes of 28 consecutive myopic patients underwent topography-guided LASIK surgery using the Allegretto excimer laser system. We plan to enroll and report on 60 eyes of 30 subjects. Topography-guided treatments were captured and planned on the Contoura topolyzer system. Mean pre-operative spherical equivalent refraction was -3.39 +/-1.80 diopters. Mean pre-operative cylinder was and -0.66 +/- 0.75 diopters. Epithelial thickness maps were analyzed centrally, superiorly, inferiorly, nasally and temporally preoperatively and at post-operative months one, three and six.

Results
At post-op month six, mean spherical equivalent refraction was -0.01 +/- 0.30 diopters. Mean cylinder was -0.27 +/- 0.27 diopters. At post-op month six, 100% of eyes had an UDVA of 20/20 and 75% of eyes had an UDVA of 20/16. No eyes lost one or more lines of corrected distance visual acuity at the six-month postoperative visit. AS-OCT demonstrated progressive thickening of the central and paracentral corneal epithelium with progressive thinning of the peripheral corneal epithelium over the six month postoperative time period.

Conclusion
Topography-guided LASIK is safe, effective and predictable in the treatment of patients with myopia and compound myopic astigmatism. Progressive changes in corneal epithelial thickness maps were seen between the pre-operative visit and the six post-operative month visit.
Clinical Outcomes after Topography-Guided LASIK: Planning with a New Topographic-Analysis Algorithm Versus Using the Manifest Refraction.
Author
Mark C. Lobanoff, MD, ABO

Purpose
All previous forms of LASIK treatments have been planned solely from the manifest refraction. In the FDA study for topography-guided LASIK, treatments were planned using the manifest refraction. Would new topographic-analysis software yield better clinical results in patients than planning topography-guided LASIK using manifest refraction alone?

Methods
A double-arm retrospective chart review, a comparative non-interventional study of postoperative refraction and visual acuity two to three months after uncomplicated LASIK using Contoura on the Wavelight laser. Clinical results from four surgeons at four sites were used. Surgical planning had to be based on either the manifest refraction (Group M) or the Phorcides analytical engine (Group P), with nomogram adjustments permitted. The manifest refraction and visual acuity (corrected and uncorrected) from two to three months after surgery had to be available. Each surgeon contributed 80 eyes treated with the Phorcides planning software and 80 eyes that treated using the manifest refraction.

Results
Clinical results from a matched group of 317 Manifest eyes and 323 Phorcides eyes. Residual refractive results, both sphere and cylinder, were similar between groups. However, significantly more eyes had 20/16 or better (-0.1 logMAR) UCVA (62.5% Phorcides, 41.3% Manifest) and BCVA (77.1% Phorcides, 51.4% Manifest) in the Phorcides group. All eyes but one had a BCVA of 20/20 or better after surgery. The number of patients with a UCVA better than their preoperative BCVA was significantly higher in the Phorcides group (36.5%) relative to the Manifest group (23.0%).

Conclusion
Using the Phorcides analytical engine for topography-guided surgery planning increased the likelihood of 20/16 UCVA and BCVA relative to using the manifest refraction.
Prospective Comparison of Prowl Outcomes to Ocular Scatter Index in Advanced Custom Femtosecond LASIK
Author
James C. Loden, MD

Purpose
To evaluate pre-op and post-op PROWL outcomes to pre-op and post-op ocular scatter index thus determining optimum pre-op ocular scatter index and if ocular scatter index increases with myopic astigmatic LASIK.

Methods
Prospective study of 50 patients (100 eyes) having bilateral iDesign 2.0 custom femtosecond LASIK with all eyes targeted for post-op plano refraction. Pre-op and post-op PROWL data was collected. Pre-op and post-op ocular scatter index was measured using the HD Analyzer. All post-op data was collected at the three month post-operative visit.

Results
Results will be completed by March 2020. 43/50 patients are currently enrolled. Initial outcomes are showing near 100% satisfaction with LASIK and would recommend LASIK to a friend or family member. Ocular scatter index is remaining stable and in some cases improved.

Conclusion
Advanced custom wavefront guided LASIK for mild to moderate myopia with astigmatism can produce PROWL outcomes that exceed prior national PROWL 1 and PROWL 2 studies. Ocular scatter index profiles dispel myth that LASIK decreases visual quality.
A Retrospective Study of Factors Related to Regression after LASIK/LASEK for Myopia over a 20-Year Period.
Authors
Ciara E. O'Byrne, MBBS
Michael O'Keefe, FRCS

Methods
A retrospective review was conducted of the medical records of all cases of regression following laser in situ keratomileusis (LASIK) or laser-assisted subepithelial keratectomy (LASEK) over a 20-year period in the Mater Private Hospital. We recorded patient demographics; age at initial presentation, initial refraction and initial post-operative unaided visual acuity; length of time to re-treatment; age, unaided visual acuity, refraction at re-treatment and post-operative visual acuity.

Results
Preliminary data of 221 patients was analysed. There were 140 cases of LASIK regression and 81 cases of LASEK regression. In terms of gender, 167 patients were female and 54 patients were male. The mean age at initial surgery was 37 years (range 19-72 years). The mean age at retreatment was 41 years. There was an average of 5.49 years to retreatment, with 37.23% of patients requiring retreatment within 1 year of initial surgery. Neither occupation nor initial degree of myopia appeared to be related to regression.

Conclusion
Regression is a significant issue after LASIK/LASEK refractive surgery. It does not appear to be related to either age, occupation or primary refraction.
Biomechanical Changes during LASIK Corneal Flap Creation Leading to Incorrect Topographic Guided Ablation (Contoura) Outcomes.
Author
Manoj V. Motwani, MD

Purpose
Biomechanical changes occurring in certain corneas were noted to change corneal shape during LASIK flap creation, causing incorrect eccentric corneal ablation and outcomes during topographic guided laser (Contoura) correction.

Methods
220 consecutive primary eyes corrected with Contoura utilizing the LYRA Protocol were examined retrospectively for eyes that did not achieve the desired correction within 0.25D. All were primary LASIK procedures utilizing either a Moria microkeratome or the Alcon Wavelight FS200 femtosecond laser for flap creation, and all eyes had excimer ablation via the Alcon Wavelight EX500 by one surgeon at one laser center. Data was analyzed for vision, refraction, and topographic changes.

Results
Evaluation of the 220 eye set revealed that 12 eyes had eccentric irregular ablation patterns, demonstrating a change of shape and refractive efficiency during the LASIK procedure. This resulted in a post-op astigmatic refraction along the axis of the ellipse, and this refraction did not change with time. All of these eyes had thicker than average corneas, with the thinnest part of the cornea displaced peripherally from the corneal apex. It was surmised that the corneas changed shape bio-mechanically during LASIK flap creation, changing the shape which no longer matched the pre-operative topography. This resulted in an erroneous topographic guided ablation.

Conclusion
Certain corneas that have a peripherally displaced thinnest point from the corneal apex can bio-mechanically change during LASIK flap creation, resulting in an incorrect laser ablation outcome.
Quality of Life and Satisfaction Among Physicians after Wavefront-Optimized Versus Topography-Guided Laser Vision Correction
Authors
Ronald R. Krueger, MD, MSE
Jeffrey H. Ma, MD
Angelique Pillar, MD

Methods
A 12-question retrospective survey was sent to all physicians who underwent laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) by a single surgeon (RRK) at the Cole Eye Institute between 2011 and 2018 using the Alcon WaveLight® Allegretto Wave® Eye-Q or EX500® excimer Laser systems (Fort Worth, TX, USA). Visual outcomes were obtained from patient charts of both WFO and TG profiles, and comparative statistical analysis was performed using Fisher’s exact test (Prism version 8.0, GraphPad software, La Jolla, CA)

Results
Two hundred and thirty-five physicians (454 eyes) met the inclusion criteria for our study, including 181 physicians (353 eyes) who underwent WFO LVC and 54 physicians (101 eyes) who underwent TG LVC. One hundred seventeen physicians (49.8%) responded to the survey and reported an overall satisfaction rate of 97.8% among WFO patients with 95.5% saying they would have the procedure again and an overall satisfaction rate of 100% among TG patients with 100% saying they would have the procedure again. Visual outcomes showed a high level of efficacy and safety, with a higher percentage of 20/10 vision (22% vs. 4%, p<0.0001) and 20/15 vision (87% vs 69%, p<0.01) among the TG eyes vs. the WFO eyes.

Conclusion
Physicians who have undergone LVC using either wavefront-optimized or topography-guided excimer laser profiles report high satisfaction and quality-of-life improvements with good visual outcomes. The rate at which physicians elected to undergo refractive surgery is on the rise, indicating an increasing confidence in LVC among physicians over time.
Clinical Outcomes of LASIK and PRK Performed By Cornea Fellows
Authors
Gabriel S. Valerio, MD, ABO
Edward E. Manche, MD

Purpose
To describe quality of vision outcomes of LASIK and PRK performed by cornea fellows.

Methods
This study is a prospective cohort study that evaluates quality of vision outcomes of patients who underwent LASIK and PRK performed by cornea fellows at the Stanford Eye Laser Center. To date, 26 patients (46 eyes included) are enrolled in the study. 18 eyes have undergone LASIK and 28 have undergone PRK. The main outcome measures include visual symptoms (double images, glare, halos, starbursts), dry eye symptoms, and overall satisfaction with vision evaluated preoperatively and at postoperative month 3, 6, and 12.

Results
Preoperative uncorrected visual acuity averaged 1.31 +/- 0.52 LogMAR ranging from 0.2 to 1.80 LogMAR and postoperative uncorrected vision was 0.04, 0.01, -0.02 at postoperative month 1,3, and 12, respectively. Spherical equivalent preoperatively was -4.2 diopters and postoperative spherical equivalent was -0.02, -0.01, -0.13 at postoperative month 1,3, and 12 respectively. In regards to visual symptoms: Difficulty driving, activities of daily living, frequency and bothersomeness of glare and halos; all trended towards decreasing with improvement over preoperative levels. Although starbursts frequency decreased at postoperative month 12 they appeared to be more bothersome.

Conclusion
Overall, fellow performed refractive surgery resulted in excellent clinical outcomes and predictability. Results of quality of vision outcomes as evaluated by questions from the PROWL survey, suggests that visual symptoms to include glare, halos and starbursts all decrease in frequency by postoperative month 12. Study enrollment is ongoing.
Topography-Guided LASIK Surgery: Preliminary Six-Month Results of a Prospective Study
Authors
Edward E. Manche, MD
Gabriel S. Valerio, MD, ABO

Purpose
To prospectively evaluate outcomes of topography-guided LASIK in the treatment of myopia and compound myopic astigmatism. Outcome measures include high contrast snellen acuity, low contrast snellen acuity (5 and 25%), safety, predictability, efficacy, HOA analysis, changes in epithelial thickness maps using anterior segment OCT (AS-OCT).

Methods
Fifty-six eyes of 28 consecutive myopic patients underwent topography-guided LASIK surgery using the Allegretto excimer laser system. We plan to enroll and report on 60 eyes of 30 subjects. Topography-guided treatments were captured and planned on the Contoura topolyzer system. Mean pre-operative spherical equivalent refraction was -3.39 +/-1.80 diopters. Mean pre-operative cylinder was and -0.66 +/- 0.75 diopters. Epithelial thickness maps were analyzed centrally, superiorly, inferiorly, nasally and temporally preoperatively and at post-operative months one, three and six.

Results
At post-op month six, mean spherical equivalent refraction was -0.01 +/- 0.30 diopters. Mean cylinder was -0.27 +/- 0.27 diopters. At post-op month six, 100% of eyes had an UDVA of 20/20 and 75% of eyes had an UDVA of 20/16. No eyes lost one or more lines of corrected distance visual acuity at the six-month postoperative visit. AS-OCT demonstrated progressive thickening of the central and paracentral corneal epithelium with progressive thinning of the peripheral corneal epithelium over the six month postoperative time period.

Conclusion
Topography-guided LASIK is safe, effective and predictable in the treatment of patients with myopia and compound myopic astigmatism. Progressive changes in corneal epithelial thickness maps were seen between the pre-operative visit and the six post-operative month visit.
Outcomes of Planning Topography-Guided LASIK with New Analytic Software Vs. Planning with Manifest Refraction in Eyes with Tcat Parameters.
Authors
Karl G. Stonecipher, MD, ABO
Mark C. Lobanoff, MD, ABO
Tom S Tooma, MD
Stephen A. Wexler, MD, ABO

Purpose
The TCAT FDA study produced excellent visual results. We looked at how patient outcomes would compare using a new analytical software versus the traditional planning using FDA study guidelines.

Methods
Eyes in the TCAT study were restricted to differences between the measured axis of astigmatism and the manifest refraction astigmatism of only 10 degrees if >2 D of astigmatism was present. With <1.75 D of astigmatism they could differ by >10 degrees. Their magnitude could differ by <0.75 D. This study is a double-arm retrospective chart review, a comparative study of postoperative refraction and visual acuity three months after LASIK using topography-guided LASIK. Clinical results from four surgeons at four sites were used. Surgical planning based on either the manifest refraction or the Phorcides analytical.

Results
At the 3 month post-op visit, eyes (N-270) treated with planning from the manifest refraction and those treated with the new analytic software had 91% and 97% of eyes achieving 20/20 UCVA. However, the new analytic software produced statistically significantly (0.001) more eyes with 20/15 UCVA than those eyes treated with manifest refraction planning. No eyes were enhanced.

Conclusion
When new topographic-analysis software is used to plan topography-guided LASIK treatments, more eyes achieve 20/15 UCVA at 3 months than eyes treated solely off the manifest refraction even in the cohort of patients in which manifest refraction has historically produced its best results.
Patient Outcomes in Topography Guided Corneal Refractive Surgery: An Analysis of the AAO IRIS® Registry (No Audio)
Authors
Michael Gordon, MD
Mohinder Merchea, OD, PhD
Jessica Mathew, OD, PhD

Purpose
To investigate the outcomes among patients who had refractive surgery on the Wavelight excimer laser using a topography guided algorithm (Contoura).

Methods
A non-interventional, retrospective database analysis of the IRIS® Registry using a cohort of 971 eyes that had undergone topography guided corneal refractive surgery from January 1, 2016 to March 31, 2019. Analysis was limited to those patients that had at least 30-day post-op data. The primary outcomes were mean refractive error and change in visual acuity, overall and for low or high myopia.

Results
The IRIS database showed post-op mean decimal UDVA of 1.10 (SD 0.78) (20/20+) at 30 days after Contoura treatment in 971 eyes. VA beyond 30days, pre/post-op refraction and other relevant post-op data were not available in this database. A separate analysis of the IBRA database in those receiving Contoura (n=297) during the same timeframe showed similar mean decimal UDVA of 1.12 (SD 0.19) at 30 days post-op. IBRA pre-op refraction data showed mean sphere of -4.54D (SD 2.05; range -1D to -9.5D) and mean cyl of -0.84D (SD 0.87; range 0D to +4.25D). Post-op mean refraction data at 30days for sphere was -0.03D (SD 0.20; range +1.00D to -1.50D) and for cyl -0.07D (SD 0.21; range 0D to +1.50D).

Conclusion
Contoura provided excellent post-op UDVA shown by 2 databases. While IRIS provided a large sample size for evaluation of post-op VA, it was lacking sufficient refraction data. IBRA database showed minimal residual sphere and cyl after treatment. Surgeons should be entering refraction pre/post-op data into IRIS to improve future real-world analyses.

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