Flap striae requiring surgeon intervention occurred in 0.79% of eyes. Higher preoperative SE values were associated with an exponential increase risk for striae. Treatment by lifting and irrigation significantly improved the accuracy, efficacy, and safety to a level close to that of contralateral control eyes, although striae-treated eyes were more likely to need excimer laser retreatment.

T opography-guided excimer ablation uses highresolution corneal topographic height maps to generate a customized ablation profile consisting of anterior corneal higher order aberrations (HOAs) and an accurate measure of the anterior corneal astigmatism (ACA). Topography-guided custom ablation treatment (T-CAT, now called Contoura) (Alcon Laboratories, Inc., Fort Worth, TX; Contoura in the United States) has been approved by the U.S. Food and Drug Administration (FDA) for primary laser in situ keratomileusis (LASIK) in myopic and myopic astigmatism eyes, with resulting good efficacy and safety. 1 However, this trial and its subsequent publication excluded eyes with naturally occurring irregular astigmatism. Healthy corneas with skewed radial axes, non-orthogonal cylinder, and asymmetric bowties were excluded to standardize the preoperative cohort, maximize outcomes, and avoid refractive surprises. 1,2 T-CAT refractive predictability can be a concern with increasing corneal irregularities and elevated anterior corneal HOAs. 3 Eyes with greater cylinder magnitude, particularly those with irregular astigmatism, have more anterior corneal HOAs. 4,5 They also have a greater discrepancy between subjective refractive astigmatism and topography-measured ACA, 6

PurposeCollagen cross-linking (CXL) for post-laser-assisted in situ keratomileusis (LASIK) ectasia (PLE) is traditionally performed either epi-on or epi-off on the corneal surface. This study describes a novel technique in treating early PLE with under-flap CXL (ufCXL) to the stromal bed and reports on 6-month outcomes.Patients and methodsCase series of seven patients (eight eyes) with topography-diagnosed early PLE treated with ufCXL. Inclusion criteria were early, mild PLE defined as new-onset postoperative manifest refraction cylinder ≤1.50 D, with new topographic inferior steepening consistent with ectasia, uncorrected distance visual acuity (UDVA) of 20/40 or better, and corrected distance visual acuity (CDVA) of 20/25 or better. Existing LASIK flap was lifted, riboflavin was applied directly to the stromal bed, flap was repositioned, and 18 mW/cm2 ultraviolet light was applied for 3 minutes to the corneal surface. Post-ufCXL manifest refraction, UDVA and CDVA, corneal cylinder, Kmax, and corneal irregularity index were compared with pre-ufCXL measurements.ResultsPatients had a pre-ufCXL sphere of 0.09±0.48 D and cylinder of −0.78±0.49 D. At 6 months, post-ufCXL sphere (0.06±0.8 D; P=0.89) and cylinder (−1.09±0.76 D, P=0.26) were unchanged. Cumulative post-ufCXL UDVA was unchanged, achieving 20/20, 20/30, and 20/40 in 25%, 88%, and 88%, respectively, compared with 13%, 63%, and 88% pre-ufCXL (P=0.68). Post-ufCXL CDVA was unchanged (P=0.93) with a gain of one line in two eyes, a loss of one line in one eye, and five eyes unchanged. The efficacy index (P=0.76), safety index (P=0.89), Kmax (P=0.94), and corneal irregularity index (P=0.73) were also unchanged.ConclusionPreliminary results with ufCXL for early PLE are promising, demonstrating maintenance of visual accuracy, efficacy, safety, Kmax, and cylinder, with much quicker recovery times than surface CXL.

Background: To evaluate laser-assisted in situ keratomileusis (LASIK) outcomes, subjective quality of vision (QoV) and patient satisfaction in eyes with very high myopia (VHM) above − 10.00 diopters (D). Methods: Consecutive myopic and myopic-astigmatism eyes with spherical equivalent (SEQ) ranging between − 10.00 to − 13.50 D underwent LASIK with the WaveLight® Allegretto Wave® Eye-Q 400 Hz excimer laser. Treatment accuracy, efficacy, safety, stability, cylinder vectors, and higher-order aberrations were evaluated, together with subjective QoV and night vision disturbances (NVDs). Results: 114 eyes had a preoperative SEQ of − 11.02 ± 0.81 D, with a median follow-up of 24 months. A total of 72, 84, and 94% of eyes were within ± 0.50, ± 0.75 and ± 1.00 D of intended SEQ (R 2 = 0.71). The efficacy index was 0.93 ± 0.20, with 51 and 81% of eyes achieving 20/20 and 20/25. The astigmatism correction index was 0.95 ± 0.33. The safety index was 1.05 ± 0.12. The average myopic regression was − 0.51 ± 0.38 D. Preoperative QoV scores improved significantly postoperatively (7.5 ± 0.8 vs. 9.1 ± 0.7; P < 0.001), with less NVDs (P < 0.001). Total, spherical and coma root mean square (RMS) postoperative ocular higher-order aberrations were 1.07 ± 0.34, 0.67 ± 0.25, and 0.70 ± 0.40 μm. Conclusions: Very high myopia LASIK between − 10.00 to − 13.50 D is safe and results in good visual outcomes, with high patient satisfaction and a significant improvement in patient-reported QoV after surgery. Appropriately selected patients within this very high myopia group can be included as LASIK candidates.

Purpose: To investigate whether adding accelerated under-flap corneal cross-linking to hyperopic laser in situ keratomileusis (LASIK-ufCXL) affects postoperative stability and regression, visual and refractive outcomes, and subjective quality of vision. Methods: This prospective comparative contralateral eye study included 51 patients with hyperopia (102 eyes) who received LASIK-ufCXL in the eye with highest defocus equivalent (DEQ) or randomized when DEQ equal, with the contralateral control eye receiving LASIK alone. After excimer ablation, 0.25% riboflavin was instilled on the stromal bed for 3 minutes. The flap was repositioned, followed by a total irradiation dose of 3.24 J ultraviolet A (UV-A) light administered to the corneal surface, using 18 mW/cm 2 UV-A for 3 minutes. Postoperative hyperopic regression (stability) was the primary outcome measure, defined by the difference in spherical equivalent (SEQ) at 1 week and 24 months postoperatively. Secondary measures reported uncorrected distance visual acuity, corrected distance visual acuity, cylinder vector analysis, subjective quality of vision, subjective night vision disturbances, and corneal haze. Results: At 24 months, the SEQ stability ( P = .4273) and the magnitude of hyperopic regression ( P = .5613) did not significantly differ between groups, with a small trend showing hyperopic regression of 0.50 diopters or greater being less frequent in LASIK-ufCXL eyes. There were no significant differences in accuracy, efficacy, and safety ( P > .05), with a small trend of more residual refractive astigmatism in the LASIK-ufCXL group ( P = .3216, Cohen's d : −0.29). Subjective quality of vision trended inferior in LASIK-ufCXL eyes ( P = .2237, Cohen's d : −0.25), with a greater haze grading ( P = .0466, Cohen's d : 0.41). Conclusions: Postoperative regression and stability were statistically equivalent between hyperopic LASIK vs LASIK-ufCXL, with identical safety. There were small clinical trends of lower efficacy, accuracy, and subjective quality of vision in LASIK-ufCXL eyes. [ J Refract Surg . 2022;38(12):770–779.]