Refractive Corneal Lenticule Extraction With the CLEAR Femtosecond Laser Application.

PURPOSE: The aim of this study was to evaluate a new femtosecond laser application for refractive corneal lenticule extraction with suction control and computerized regulation of centration and alignment (Ziemer CLEAR). METHODS: This was a retrospective, consecutive, noncomparative case series study. Patients undergoing CLEAR for spherical equivalent (SE) between -3 and -10 D, evaluating SE, defocus equivalent, refractive astigmatism, visual acuity, and centration at 10 months were evaluated in the study. RESULTS: Fifty-three eyes of 42 patients (mean age 40.4 ± 8.6 years) were included, with preoperative SE -5.99 ± 1.49 D and mean corrected distance visual acuity (CDVA) of 0.05 ± 0.07 logMAR. With no suction losses, an intact lenticule was extracted in all eyes. In 6 eyes, peripheral adhesion was resolved by lenticulerrhexis, and in 1 eye, the incision was opened by a crescent blade. Moderate interface inflammation occurred in 3 eyes. At day 1, in the 42 eyes with uneventful surgery, the mean CDVA was 20/27, whereas in the 11 eyes with extra surgical manipulations, it was 20/36 ( P = 0.04). At 10 months, for the 53 eyes, the mean uncorrected distance visual acuity was 0.05 ± 0.09 logMAR; in 37 eyes (70%), it was 20/25 or better; and the mean CDVA was 0.04 ± 0.06 logMAR. Eight eyes (15%) lost 1 logMAR line. The mean SE was -0.13 ± 0.15 D. The mean defocus equivalent was 0.33 ± 0.32 D, with 46 eyes (87%) ≤0.50 D and 52 eyes (98%) ≤1 D. Refractive astigmatism was ≤0.50 D in 48 eyes (90%). The efficacy index was 1.00, and the safety index was 0.98. The mean decentration from the corneal vertex was 0.28 ± 0.07 mm. CONCLUSIONS: The application yielded good predictability, efficacy, and safety. Slower visual recovery was observed after extra surgical manipulations.

Change in Stromal Thickness and Anterior Curvature After Refractive Corneal Lenticule Extraction With the CLEAR Application.

PURPOSE: To measure the changes in stromal thickness and anterior corneal curvature after corneal lenticule extraction for the correction of myopia and myopic astigmatism with the Corneal Lenticule Extraction for Advanced Refractive correction (CLEAR) application (Ziemer Group). METHODS: The correlations between achieved correction on maximum myopic meridian and stromal thinning and spherical equivalent of achieved correction and anterior corneal flattening were evaluated by optical coherence tomography 6 months after CLEAR in 78 eyes of 78 patients in a retrospective, consecutive, non-comparative case series study. RESULTS: With an optical zone of 6.5 mm (52 eyes), the mean correction achieved was -5.80 ± 1.52 diopters (D) (range: -2.25 to -9.25 D), the mean stromal thinning was 104 ± 15 µm (range: 76 to 138 µm), and the regression line was: µm of thinning = 8.46 • D of correction + 55.25. With an optical zone of 6 mm (26 eyes), the mean correction achieved was -8.33 ± 1.61 D (range: -5.50 to -11.00 D), the mean stromal thinning was 114 ± 12 µm (range: 93 to 144 µm), and the regression line was: µm of thinning = 6.35 • D of correction + 60.92. With 6.5 mm, the mean corneal flattening was 4.27 ± 0.88 D, and the regression line was: D of flattening = 0.50 • D of correction + 1.60. With 6 mm, the mean corneal flattening was 6.40 ± 0.70 D, and the regression line was: D of flattening = 0.37 • D of correction + 2.36. CONCLUSIONS: Stromal thinning and anterior corneal flattening were correlated with the amount of myopic correction in a linear fashion. The thinning was significantly less than predicted by the laser software. [J Refract Surg. 2022;38(12):797-804.].

Refractive Corneal Lenticule Extraction on Previous Photorefractive Keratectomy, with Optical Coherence Tomography Study.

We report the first case of refractive corneal lenticule extraction with the femtosecond laser application CLEAR as retreatment technique after previous laser vision correction. A 42-year-old woman, operated by bilateral photorefractive keratectomy (PRK) 19 years previously, with moderate dry eye, came for post-PRK regression and underwent correction of a residual myopia of -3 -0.5 × 159° D in the left eye by CLEAR. Surgery was uneventful, with a regular laser pattern and a normal dissection of the lenticule. At day 1, uncorrected visual acuity was 20/25; at 3 months, it was 20/20, with a refraction of +0.25 × 115° D. The cornea and interface were regular and transparent; no dry eye symptoms occurred. At 3 months, on optical coherence tomography, the treatment was well centered, the surgical interface was centrally regular, whereas the anterior profile of the stromal surface was slightly corrugated, compensated by a smooth epithelial surface. The present case demonstrates that myopia after PRK can be achieved by CLEAR; an irregular stromal surface may occur, not affecting the visual result in virtue of epithelial remodeling.

Traumatic Flap Complications After Femtosecond LASIK.

PURPOSE: The purpose of this article was to evaluate the prognosis of traumatic flap dislocation or avulsion in a large series of laser-assisted in situ keratomileusis (LASIK) cases. METHODS: Retrospective, consecutive, noncomparative case series analyzes the visual and anatomical results after flap dislocation or avulsion, caused by trauma occurred at least 1 month after LASIK. RESULTS: A total of 37,315 eyes of 19,602 patients were reviewed. A traumatic flap complication was observed in 9 eyes of 9 patients, with a maximum interval of 37 months after surgery. Flap dislocation with central full-thickness folds was found in 5 cases; flap lifting and repositioning achieved a full recovery of uncorrected visual acuity. In another case, a partially detached flap was repositioned by a microsponge without lifting; self-limiting localized epithelial ingrowth followed. In 3 eyes, a complete flap avulsion occurred and, after epithelialization, a moderate refractive change was observed, comprised between -0.25 and -1 diopters (D) of spherical equivalent, with astigmatism <1 D; in 1 eye, the resulting myopia was corrected by repeat femtosecond LASIK. CONCLUSIONS: Traumatic flap complications after femtosecond LASIK are rare but can occur even in the long term; they have a favorable anatomic and visual prognosis.

Diffuse lamellar keratitis after LASIK with low-energy femtosecond laser.

PURPOSE: To evaluate the incidence, evolution, and prognosis of diffuse lamellar keratitis (DLK) in a large series of laser in situ keratomileusis (LASIK) with low-energy femtosecond laser. SETTING: Private practice, Siena, Italy. DESIGN: Retrospective, consecutive, noncomparative case series study. METHODS: Single-use instruments, powder-free gloves, and no corneal marking were used. Flap was created by a low-energy femtosecond laser (Ziemer Z2 and Z4). RESULTS: A total of 37 315 eyes of 19 602 patients were reviewed. DLK was observed in 236 eyes (0.63%) of 149 patients (0.76%). Grade 1 DLK was observed in 231 eyes of 142 patients, grade 2 in 1 eye: when treated with topical steroids, they had no visual consequences. Three patients had bilateral grade 3 to 4 DLK: one of them, with bilateral grade 3, despite flap lifting and irrigation worsened to stage 4 (central stroma thinning and flattening), partially recovered in 2 years, and underwent repeat femtosecond laser-assisted LASIK for hyperopic shift in 1 eye. In all the 5 eyes that developed grade 4 DLK, corneal thickness decreased until the first month and then partially recovered; mean final tissue loss at 1 to 2 years was 35 µm. Compensatory epithelial thickening was observed. CONCLUSIONS: DLK after low-energy femtosecond laser-assisted LASIK is rare; severe DLK (stages 3 and 4) was found in only 6 eyes (0.016%). Flap lifting and irrigation might not prevent progression. Spontaneous reformation of stromal tissue and epithelial thickening improve visual acuity in the long term; residual hyperopic shift can be corrected by repeat femtosecond laser-assisted LASIK.

Changes in ocular biomechanics after femtosecond laser creation of a laser in situ keratomileusis flap.

PURPOSE: To evaluate ocular biomechanical parameters with the Corvis ST, a noncontact tonometer combined with an ultra-high-speed Scheimpflug camera, before and after creation of a femtosecond laser-created laser in situ keratomileusis (LASIK) flap. SETTING: Private practice, Siena, Italy. DESIGN: Prospective consecutive study. METHODS: Right eyes of patients having LASIK were assessed with the dynamic Scheimpflug camera before and after femtosecond laser (LDV Z4) flap creation but before mechanical flap lifting. RESULTS: Twenty-eight eyes of 28 patients were evaluated. Before flap creation, the mean values on the dynamic Scheimpflug camera were intraocular pressure (IOP), 15.04 mm Hg ± 3.99 (SD); central pachymetry, 550.8 ± 101.0 µm; applanation 1 length, 1.721 ± 0.134 mm; applanation 2 length, 1.674 ± 0.287 mm; applanation 1 velocity, 0.126 ± 0.031 m/s; and deflection amplitude, 1.039 ± 0.141 mm. After flap creation, the mean values were IOP, 16.10 ± 3.11 mm Hg (95% confidence interval [CI], 0.44-1.78; P < .05); central pachymetry, 561.8 ± 35.9 µm (95% CI, -28.9 to 50.9; P = .21); applanation 1 length, 1.789 ± 0.1492 mm (95% CI, 0.003-0.134; P < .05); applanation 2 length, 1.759 ± 0.259 mm (95% CI, -0.005 to 0.173; P = .08); applanation 1 velocity, 0.136 ± 0.022 m/s (95% CI, 0.001-0.017; P < .05); and deflection amplitude, 1.029 ± 0.151 mm (95% CI: -0.043 to 0.025; P = .34). CONCLUSION: The dynamic Scheimpflug camera showed changes in biomechanical properties after femtosecond creation of a LASIK flap as indicated by an increased applanation 1 length and applanation 1 velocity. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Femtosecond-assisted laser in situ keratomileusis for consecutive hyperopia after radial keratotomy.

PURPOSE: To evaluate femtosecond-assisted laser in situ keratomileusis (LASIK) for the treatment of hyperopic shift after radial keratotomy (RK). SETTING: Private practice, Siena, Italy. DESIGN: Prospective case series. METHODS: Eyes with a spherical equivalent (SE) of +1.0 diopters (D) to +4.0 D after RK with 6 or 8 incisions had LASIK. The flap (nominal thickness 130 µm) was created with a femtosecond laser (LDV Z2); the refractive ablation was performed with an excimer laser (217P). The flap was dissected in a centrifugal fashion along previous RK cuts. RESULTS: Eighteen eyes of 10 patients were treated. Preoperatively, the mean defocus equivalent was 3.13 diopters (D) ± 0.71 (SD); the corrected distance visual acuity (CDVA) was 0.09 ± 0.06 logMAR. At 9 months, the mean defocus equivalent was 0.51 ± 0.47 D (P < .05), with 13 eyes (72%) having 0.50 D or less of defocus equivalent and 16 eyes (89%) having 1.0 D or less of defocus equivalent. The mean CDVA was 0.04 ± 0.06 logMAR (P < .05). No lines of logMAR CDVA were lost. The mean uncorrected distance visual acuity was 0.11 ± 0.10 logMAR. The safety index was 1.11; the efficacy index was 0.97. No retreatments were performed. Flap complications were limited to an RK incision opening larger than 2 mm in 3 eyes and 1 case of a small, self-limiting epithelial ingrowth. CONCLUSION: Laser in situ keratomileusis with a low-energy femtosecond laser was a safe and effective approach to treat post-RK hyperopia, causing no relevant inflammation. FINANCIAL DISCLOSURE: Neither author has a financial or proprietary interest in any material or method mentioned.

Clinical results of ZSAL-4 angle-supported phakic intraocular lenses in 190 myopic eyes.

PURPOSE: To evaluate the efficacy and safety of angle-supported phakic intraocular lenses (IOLs) in myopia. SETTING: Private practice, Siena, Italy. METHODS: This prospective noncomparative single-surgeon interventional case series comprised 190 consecutive myopic eyes of 115 patients having implantation of a ZSAL-4 IOL (Morcher GmbH) through a 5.5 mm x 3.0 mm sclerocorneal tunnel along the steepest meridian with a surgical iridectomy. Preoperatively, the mean spherical equivalent was -14.37 diopters (D) +/- 4.40 (SD) and the mean astigmatism, 1.66 +/- 1.36 D. RESULTS: Postoperatively, the mean defocus equivalent (DEQ) was 1.55 +/- 1.06 D and the mean astigmatism, 1.41 +/- 1.11 D. The mean surgically induced astigmatism (vector analysis) was 1.03 +/- 0.77 D (95% confidence interval [CI], 0.92 to 1.15); 146 eyes (77%) were within +/-2.0 D of the DEQ, 76 eyes (40%) were within +/-1.0 D, and 36 eyes (19%) were within +/-0.5 D. The safety index was 1.25 and the efficacy index, 0.78. The improvement in best spectacle-corrected visual acuity (0.17) was statistically significant (95% CI, 0.14 to 0.2). Complications were intraocular pressure spike due to topical steroids, 18%; chronic iridocyclitis, 1%; explantation of unstable IOL, 1%; explantation of IOL for iridocyclitis, 0.5%; pupil ovalization, 11%; halos, 18%; and macular hemorrhage, 1%. CONCLUSIONS: Angle-supported IOLs can effectively correct high myopia, although residual refractive errors may require secondary procedures. The main intraoperative and postoperative complications were halos, steroid response, and incorrect IOL sizing. The role of surgery in inducing macular hemorrhages should be assessed further.

Angle-supported phakic intraocular lenses in eyes with keratoconus and myopia.

PURPOSE: To evaluate the visual results and complications of angle-supported phakic intraocular lenses (IOLs) to correct myopia associated with early-stage keratoconus. SETTING: Private practice, Siena, Italy. METHODS: In a prospective noncomparative single-surgeon interventional case series, outcomes in 12 consecutive eyes of 8 patients with stage I to II keratoconus, myopia from -6.50 to -14.00 diopters (D), and astigmatism from -1.00 to -5.00 D were analyzed after the implantation of angle-supported phakic IOLs (ZSAL-4, Morcher). The minimum follow-up was 12 months. Implantation was performed through a sclerocorneal 5.5 mm x 3.0 mm tunnel along the steepest meridian, after which a surgical basal iridectomy was created. RESULTS: The spherical error in all cases was corrected within +/-1.00 D. Astigmatism magnitude did not significantly improve. The uncorrected visual acuity (UCVA) was 20/40 or better in all cases. The best spectacle-corrected visual acuity (BSCVA) was equal or improved in all cases. The safety index (postoperative BSCVA/preoperative BSCVA) was 1.18; the efficacy index (postoperative UCVA/preoperative BSCVA) was 0.77. Three eyes had significant halos that improved considerably over 3 months. Spectacles were permanently used by 1 patient (2 eyes in the study) and only for driving by 5 patients. Complications were limited to 3 cases of mild pupil ovalization and 1 case of IOL rotation. Endothelial loss at 12 months was 7.2%. CONCLUSIONS: Implantation of angle-supported phakic IOLs to correct myopia in patients with keratoconus stage I to II was an effective procedure. Although astigmatism did not improve by the creation of the incision, it was well tolerated by most patients. Long-term endothelial safety must be assessed.