Myopic Laser In Situ Keratomileusis Research Articles

Trifocal versus monofocal intraocular lens implantation in eyes previously treated with laser in situ keratomileusis (LASIK) for myopia.

To assess visual and refractive outcomes of trifocal intraocular lens (IOL) implantation in eyes that had previously undergone laser in situ keratomileusis (LASIK) for myopia and to compare them with those recorded after implantation of a monofocal IOL. Retrospective comparative cases series. This study evaluated uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected near visual acuity (UNVA), safety, and efficacy after the implantation of two comparable trifocal IOL models and one monofocal IOL model in patients who had previously undergone myopic LASIK. Patients were classified according to the implanted IOL (monofocal or trifocal). A total of 211 eyes from 170 patients received a monofocal IOL, and 211 eyes from 161 patients received a trifocal IOL. At the end of the study, after lensectomy, there was a higher myopic residual spherical equivalent in the monofocal group because some eyes had been targeted for slight myopia to achieve monovision; therefore, UDVA was better in the trifocal group. CDVA was comparable in both groups. As expected, both monocular and binocular UNVA were significantly better in the trifocal group. Although the percentage of eyes that lost ≥1 line of CDVA did not differ between the groups, the safety index was slightly better in the monofocal group. Although implantation of monofocal and trifocal IOLs after myopic LASIK yielded excellent distance visual outcomes, UNVA was significantly better for the trifocal IOL, with a minimally worse safety profile. Trifocal IOLs can be considered after previous LASIK for myopia, with an appropriate patient selection.

Ray-tracing-guided myopic LASIK: real-world clinical outcomes.

To assess effectiveness of individualized ray-trace based laser in situ keratomileusis (LASIK) for correction of myopia in everyday clinical practice. Single-site private practice. Retrospective nonrandomised unmasked chart review. Consecutive, myopic eyes (range ≤-8.25 diopters [D] sphere; astigmatism 0 to -4.25 D) treated with ray-trace based LASIK were included. Patients underwent wavefront, tomography, and biometry assessment using the InnovEyes Sightmap diagnostic device. The ray-trace based algorithm (InnovEyes algorithm) then generated an individualized 3D eye model and calculated a customized LASIK ablation profile. Postoperative visual acuity, refractive error and whole eye higher-order aberrations (HOAs) were evaluated over 3 months. The procedure was performed on 400 eyes (200 patients). Mean preoperative manifest refraction spherical equivalent was -3.39 ± 1.58 D (right eye -3.84 ± 1.63 D, left eye -3.98 ± 1.75 D). At month 3, uncorrected distance visual acuity (UDVA) was ≥20/20 in all eyes, ≥20/16 in 89% (right eye 90%, left eye 89%), ≥20/12 in 51% (54% right eye; 47% left eye), and 20/10 in 8% (right eye 8%; left eye 9%) of eyes respectively. UDVA was within 1 line of preoperative corrected distance visual acuity in 98% of eyes (right eye 98.5%; left eye 98%) and 39% of eyes (right eye 38%; left eye 39%) gained 1 line improvement. There was a statistically but not clinically significant increase in total HOAs (right eye 0.06 ± 0.133 μm; left eye 0.057 ± 0.125 μm; P < .001). The spherical aberration decreased (right eye -0.047 ± 0.095 μm, P < .001; left eye -0.051 ± 0.091 μm, P < .001). Ray-trace based LASIK was safe and effective for correction of myopia with and without astigmatism. Approximately, half the eyes achieved ≥20/12.5 UDVA and 8% achieved 20/10. There was no clinically significant increase in total whole eye HOAs.

Transient Light Sensitivity Syndrome (TLSS) Incidence Following Femtosecond LASIK for Myopic and Hyperopic Eyes and Femtosecond SMILE for Myopic Eyes.

To evaluate and compare the incidence of transient light sensitivity syndrome (TLSS) after myopic laser in situ keratomileusis (LASIK), hyperopic LASIK, and myopic small incision lenticule extraction (SMILE). A retrospective analysis was performed of consecutive LASIK and myopic SMILE cases, performed with the VisuMax femtosecond laser and MEL 80 or MEL 90 excimer laser (both Carl Zeiss Meditec AG) between January 2010 and February 2021 at London Vision Clinic, London, United Kingdom. A chart review was performed to find cases of clinically significant TLSS, identified as patients prescribed anti-inflammatory medications between 2 weeks and 6 months after surgery to manage photophobia. The incidence of TLSS was calculated for three groups: myopic SMILE, myopic LASIK, and hyperopic LASIK. The incidence of TLSS was then calculated for three subgroups within each treatment type based on spherical equivalent refraction treated. For myopic SMILE and myopic LASIK, it was 0.00 to -4.00 diopters (D) (low), -4.01 to -8.00 D (moderate), and -8.01 to -14.00 D (high). For hyperopic LASIK, it was 0.00 to +2.00 D (low), +2.01 to +4.00 D (moderate), and +4.01 to +6.50 D (high). The range of treatment for myopia was similar between the LASIK and SMILE groups. The incidence of TLSS was 1.2% for the myopic SMILE group, 5.3% for the myopic LASIK group, and 9.0% for the hyperopic LASIK group. The difference was statistically significant between all groups (P < .001). For myopic SMILE, the incidence of TLSS was independent of spherical equivalent refraction for low (1.4%), moderate (1.0%), and high (1.1%) myopia (P > .05). Similarly, for hyperopic LASIK, the incidence was similar for low (9.4%), moderate (8.7%), and high (8.7%) hyperopia (P > .05). In contrast, for myopic LASIK, the incidence of TLSS was "dose-dependent" on refractive error treated, with an incidence of 4.7% for low, 5.8% for moderate, and 8.1% for high myopia (P < .001). The incidence of TLSS was higher after myopic LASIK than after myopic SMILE, higher after hyperopic than myopic LASIK, and "dose-dependent" for myopic LASIK but did not vary by correction in myopic SMILE. This is the first report describing the phenomenon of late TLSS occurring between 8 weeks and 6 months after surgery, [J Refract Surg. 2023:39(6):366-373.].

Goldmann and modified Goldmann tonometry measuring intraocular pressure changes in eyes which underwent myopic laser in situ Keratomileusis and photorefractive keratectomy

PurposeCompare intraocular pressure (IOP) measured by a standard Goldmann applanation tonometer prism (IOPg) and a modified correcting applanation tonometer surface Goldmann prism (IOPc) before and after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).MethodsGoldmann tonometry was analyzed in a retrospective, cross-sectional study, using both GAT and modified-GAT prisms pre-operatively and at the 3 month post-operative appointment on 120 eyes (64 patients) who received LASIK (n = 58) or PRK (n = 62). Demographics, central corneal thickness (CCT), manifest refraction and corneal curvature (CC) data was collected at each visit as well as surgical parameters, including maximum ablation depth.ResultsMean paired IOP following LASIK decreased by − 3.28 ± 3.2 mmHg measured by IOPg and − 1.93 ± 3.3 mmHg by IOPc (p ≤ 0.0001). Mean paired IOP following PRK reduced by − 1.92 ± 3.6 mmHg measured by IOPg and − 1.06 ± 3.6 mmHg by IOPc (p ≤ 0.0001). Increased LASIK ablation depth and post-procedural change in CCT trended toward a statistically significant reduction in IOPg (p = 0.07,p = 0.12), but not IOPc (p = 0.18,p = 0.32). PRK ablation depth was not associated with a reduction in IOPg or IOPc.DiscussionThe modified Goldmann (IOPc) prism measured less of an IOP reduction following LASIK and PRK compared to the standard (IOPg) prism, and the IOP reduction with both prisms was associated with the degree of myopic correction.What is already known and the residual queryCorneal refractive surgery generally demonstrates significant postoperative Goldmann IOP reductions. Presumably, this is due to corneal biomechanical changes for which a newer method of Goldmann IOP measurement may be able to compensate.What this study addsA modified, corneal conforming Goldmann prism demonstrates significantly less IOP reduction following myopic LASIK and PRK compared to the standard flat Goldmann prism.How this study might affect research, practice or policyA newer, modified Goldmann prism may help detect glaucoma and OHT at an earlier stage in patients which have undergone LASIK or PRK. The findings corroborate predicted corneal biomechanical changes following the most common corneal refractive procedures.

Effect of corneal epithelial remodeling on visual outcomes of topography-guided femtosecond LASIK.

To assess the effect of epithelial remodeling on visual outcomes over a 9 mm diameter corneal surface after topography-guided laser in situ keratomileusis (LASIK) for myopia correction using spectral-domain anterior segment optical coherence tomography (AS-OCT). Outpatient clinical practice at the Stanford University Byers Eye Institute in Palo Alto, California. Prospective nonrandomized observational study. Visual acuity, including uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), 5% and 25% contrast sensitivity CDVA, manifest refraction, and corneal epithelial thickness after topography-guided femtosecond LASIK were analyzed. Corneal epithelial thickness was mapped across 13 sections and 3 concentric zones using AS-OCT preoperatively and at 1 month, 3 months, 6 months, and 12 months postoperatively. 60 eyes of 30 patients with a mean age of 32.8 years (range 23 to 52 ± 7.03 years) undergoing myopic LASIK correction were assessed. In eyes with complete follow-up data (n = 30), mean preoperative UDVA was logMAR 1.48 ± 0.45 and logMAR -0.11 ± 0.08 at postoperative 12 months. Mean preoperative CDVA was logMAR -0.08 ± 0.11 and logMAR -0.13 ± 0.07 at 12 months. Linear mixed modeling demonstrated a significant correlation between improvement in UDVA and decreased superior and nasal corneal epithelial thickness and between improvement in CDVA and increased central epithelial thickness 12 months postoperatively. Improvement in UDVA and CDVA at 12 months after topography-guided femtosecond LASIK was correlated with nonuniform epithelial remodeling, including epithelial thickening in the central zone and thinning in the superior and nasal sections as measured by AS-OCT.

Accuracy of the Preoperative Predicted Percentage of Tissue Altered Calculation in Refractive Surgery Planning for Myopic LASIK.

To determine the reliability of the percentage of tissue altered (PTA) calculation as part of the planning strategy for myopic laser in situ keratomileusis (LASIK) by comparing the estimated PTA provided by preoperative calculation to the postoperative PTA actually achieved in microkeratome-assisted myopic LASIK. This retrospective study included 3,624 eyes of 3,624 patients who underwent mechanical microkeratome-assisted LASIK surgery for myopic correction. The calculated preoperative PTA values based on the planned flap thickness and ablation depth were compared with the actual achieved postoperative PTA using the difference of corneal central thickness postoperatively for assessing the achieved ablation depth and the intraoperative ultrasound-assisted flap thickness measurement. Regression analysis was performed to reveal preoperative parameters that might influence PTA calculation accuracy. The mean difference between the estimated and achieved PTA was 0.451 ± 3.45% (P < .001) (95% CI: 0.3708 to 0.5322) with a preoperative and postoperative mean PTA of 31.07 ± 4.07% and 31.52 ± 5.78%, respectively. The differences between the achieved and planned maximum ablation depth and flap thickness were 4.32 ± 13.70 µm (P < .001) and -1.61 ± 13.66 µm (P < .001), respectively. Although a statistically significant difference was found between the preoperative calculated PTA and actually achieved PTA, the difference in PTA value (less than 1%) was clinically non-significant and indicated a highly reliable metric for preoperative refractive surgery planning. [J Refract Surg. 2022;38(7):422-427.].

Outcomes and Complications in Patients With Hypermobile Ehlers-Danlos Syndrome Who Have Undergone Laser In Situ Keratomileusis Surgery.

The purpose of this study was to determine the safety and outcomes of myopic laser in situ keratomileusis (LASIK) in patients who were secondarily diagnosed with hypermobile Ehlers-Danlos syndrome (EDS). We conducted a case series study on patients with hypermobile EDS who underwent myopic LASIK surgery. Visual acuity, manifest refraction, a full dilated eye examination, biometry measurements, and Scheimpflug imaging were performed in the Wilmer outpatient clinic. There were 24 eyes of 12 patients included in this study. All participants were White women with a mean age of 46.58 years (SD 8.91 years). Participants were seen at an average of 13.83 years (SD 4.3 years, range 6-21 years) after undergoing LASIK. None of the patients in the series had a diagnosis of hypermobile EDS before LASIK surgery. Overall, 92% of patients were happy they got LASIK. The uncorrected distance visual acuity was 20/20 or better in 68% of eyes, and the best-corrected visual acuity was 20/20 or better in 92% of eyes. Manifest refraction was within 1 diopter of plano in 79% of patients. Dry eye symptoms were present in 83% of patients, and 46% of eyes had either punctate epithelial erosions or decreased tear break-up time. One of the 12 patients developed corneal ectasia in both eyes. Patients with hypermobile EDS are generally satisfied with myopic LASIK correction, with good visual acuity outcomes and low rates of myopic regression. However, the risk of corneal ectasia may prevent laser vision correction from being a viable treatment option in these patients. Further studies are needed to make a definitive recommendation.

Myopic LASIK Outcomes: Comparison of Three Different Femtosecond Lasers and a Mechanical Microkeratome Using the Same Excimer Laser.

IntroductionTo compare the influence of one microkeratome and three femtosecond lasers on myopic laser in situ keratomileusis (LASIK) outcomes.MethodsRetrospective, observational cohort study. We compared 134 eyes treated with the IntraLase 60 kHz, 112 eyes treated with the Femto LDV Z6, 206 eyes treated with the FS200, and 98 eyes treated with the Hansatome zero compression microkeratome. All eyes were operated on using the same surgical protocol with the same excimer laser (Wavelight Allegretto) and were allocated to refraction-matched groups.ResultsOne day and one week postoperatively, uncorrected distance visual acuity was significantly lower in the FS200 group compared to others (P = 0.0001). This difference disappeared at the 1- and 3-month postoperative visits. Significant differences were found among groups in terms of safety index (P = 0.0001), residual sphere (P = 0.0001), and residual cylinder (P = 0.02) at the 3-month postoperative visit. No significant differences were found in corrected distance visual acuity or efficacy index.ConclusionAccording to our results, a slight delay in visual restoration after FS200 LASIK surgery might be expected. This delay was statistically significant at 1 day and 1 week postoperatively, but there were no differences from the 1-month visit onwards. Additionally, significant differences were found among devices in terms of safety index and the refractive results, which were found not to be clinically relevant.

Axial Length Evaluation before and after Myopic Corneal Refractive Surgery Using IOL Master

Purpose: To evaluate axial length before and after the photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK). Setting: Alhokama Eye Center, Riyadh Saudi Arabia. Design: A cross-sectional study. Methods: The study sample was comprised of 106 eyes of 54 patients. Patients were divided into 2 groups based on whether they had photorefractive surgery (PRK group) or laser in situ keratomiluesis (LASIK group). The intra-group comparison was performed of the changes in axial length before and after surgery using IOLMaster. P P < 0.00001, both intra-group comparisons). Conclusion: There was a statically significant decrease in the axial length measurements after PRK or LASIK for myopia.

The Importance of Using Corneal Imaging to Determine Ablation Pattern for IOL Calculations After LASIK

PURPOSE: To report a case where inaccurate intraocular lens (IOL) calculations after laser in situ keratomileusis (LASIK) occurred due to misleading historical treatment data combined with suboptimal corneal imaging prior to cataract surgery. METHODS: Case report. RESULTS: A 70-year-old woman presented elsewhere for cataract surgery. She had a history of prior myopic LASIK in both eyes with subsequent hyperopic enhancement performed in the right eye to improve near acuity. The patient had her preoperative records, which indicated that prior to LASIK her refractive error was approximately −3.75 and −4.75 diopters (D) in the right and left eyes, respectively. Based on these records, the surgeon used the American Society of Cataract and Refractive Surgeons Post-Keratorefractive Intraocular Lens Power Calculator for eyes with prior myopic LASIK for a target of −1.75 D in the right eye. Postoperatively, the patient complained of blurred vision in the right eye. Manifest refraction was −3.75 D and the patient was referred for refractive management. Review of additional corneal imaging, including Placido and Scheimpflug tangential curvature maps, showed the presence of a hyperopic treatment pattern in the right eye. IOL exchange using IOL power calculations based on prior hyperopic LASIK yielded the appropriate refractive outcome. CONCLUSIONS: This case highlights the importance of using corneal imaging rather than patient history to determine the ultimate treatment pattern induced after prior corneal refractive surgery. Tangential curvature maps are particularly useful to determine the prior ablation performed and reduce IOL calculation errors in patients with a history of corneal refractive surgery. [ Journal of Refractive Surgery Case Reports. 2022;2(1):e22–e25.]

Acanthamoeba and staphylococcal keratitis with epithelial ingrowth after laser in situ keratomileusis

Introduction: A rare case of Acanthamoeba and staphylococcal keratitis after femtosecond laser–assisted laser in situ keratomileusis (LASIK), managed medically and surgically (with flap lift, scraping, and povidone–iodine 5% application) is reported. Patient and clinical findings: A 25-year-old woman presented 30 months after myopic LASIK with a painless loss of vision in the right eye. Visual acuity was 20/32, and a focal stromal opacity was observed. Diagnosis, intervention, and outcomes: The patient underwent flap lift, scraping, and application of povidone–iodine 5% to the flap interface. Samples were sent to the microbiology department for microscopic, culture, and sensitivity, and the patient was commenced with topical fluconazole, levofloxacin, and fusidic acid. Giemsa staining demonstrated 2 Acanthamoeba cysts. Microscopic examination revealed gram-positive cocci and pyogenic cells. Culture on a nonnutrient agar with a lawn of Escherichia coli identified the gram-positive organism Staphylococcus aureus. The clinical situation improved, and topical steroids were added. Mild epithelial ingrowth was noted at 4 months after flap lift; however, the growth remained stable and was under observation. The final visual outcome was good (visual acuity 20/25). Conclusions: This case emphasized the importance of precise microbiological diagnosis and consideration of early flap lift in post-LASIK infectious keratitis.

Irregular Astigmatism Induced by Irregular Epithelial Remodeling After Conductive Keratoplasty and Transepithelial CXL

PURPOSE: To describe the evaluation and management of irregular astigmatism induced by persistent irregular epithelial remodeling in the absence of persistent underlying stromal curvature irregularity following photorefractive keratectomy (PRK) re-treatment after remote myopic laser in situ keratomileusis (LASIK) with subsequent conductive keratoplasty (CK) and transepithelial corneal cross-linking (CXL). METHODS: Case report. RESULTS: A 41-year-old woman presented for evaluation 1 year after developing blurred vision. She had irregular astigmatism in her right eye following PRK re-treatment for regression after remote myopic LASIK, with a subsequent combined CK and modified transepithelial CXL procedure 1 month after PRK. Scheimpflug tomography demonstrated a post-myopic ablation pattern with an apparent decentered optical zone. Anterior segment optical coherence tomography (AS-OCT) revealed an irregular epithelial thickness pattern, with an asymmetric focal region of epithelial thickness para-centrally temporally. Superficial keratectomy was performed. Following the procedure, the patient's uncorrected distance visual acuity improved by two lines to 20/20, and her subjective blur symptoms resolved and remained stable during 12 months of follow-up. Repeat AS-OCT demonstrated a more uniform epithelial thickness pattern. Scheimpflug tomography showed resolution of the optical zone decentration, confirming that the irregular epithelial remodeling caused the curvature irregularity, and the underlying stromal curvature was not significantly irregular at the time of treatment. CONCLUSIONS: Although uncommon, irregular epithelial remodeling can occur without permanent underlying stromal irregularity. The authors surmise that a temporary induced stromal curvature change from combined CK and transepithelial CXL regressed, but epithelial remodeling did not return to the anticipated regular postoperative pattern. This phenomenon would be unrecognizable in the absence of epithelial mapping and highlights the need for thorough evaluation and targeted management strategies to improve epithelial regularization. [ Journal of Refractive Surgery Case Reports . 2021;1(2):e23–e30.]

Comparison of Planned Versus Achieved Central Stromal Thickness Reduction in LASIK Versus SMILE: A Contralateral Eye Study.

To compare attempted versus achieved corneal stromal thickness reduction in a consecutive case series of patients undergoing laser in situ keratomileusis (LASIK) in one eye and small incision lenticule extraction (SMILE) in the other eye. This prospective, randomized, contralateral eye study included 22 consecutive patients (44 eyes), one eye randomized to have myopic LASIK and the contralateral eye to have SMILE. Anterior segment optical coherence tomography was performed preoperatively and at 3 months postoperatively. For each of the treatment groups, the achieved maximum stromal thickness reduction was compared to the planned/attempted thickness. The deviation of planned versus achieved stromal thickness reduction was then compared between the two groups. At 3 months postoperatively, LASIK had a lower difference between planned versus attempted stromal thickness reduction compared to SMILE (13.72 ± 14.45 vs 24.00 ± 19.45 µm, P = .03). Graphical analysis revealed this deviation to be exaggerated in higher myopic errors, when a higher maximum stromal reduction was planned. The mean stromal reduction thickness was 83.40 ± 29.52 µm achieved versus 97.13 ± 25.69 µm mean planned ablation depth in the LASIK group (P < .001) compared to 76.45 ± 29.69 µm achieved versus 100.45 ± 26.56 µm planned ablation depth in the SMILE group (P < .001). LASIK had a significantly lower difference between planned versus achieved stromal thickness reduction when compared to SMILE (P = .03). This difference was more apparent in higher myopic corrections. [J Refract Surg. 2021;37(7):454-459.].

Three-Year Follow-Up of Laser In Situ Keratomileusis Treatments for Myopia: Multi-Center Cohort Study in Korean Population.

This multi-center cohort study included 3401 myopic laser in situ keratomileusis (LASIK) procedures conducted in 1756 myopia patients between 2002 and 2005. Pre- and postoperative uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and manifest refraction spherical equivalent (SE) were recorded. Factors predicting low postoperative efficacy (defined as a postoperative UCVA < 0.5) were identified using univariate and multivariate logistic regression analysis. Compared with 1 month postoperatively, logMAR UCVA at 3 months postoperatively was significantly decreased (p = 0.002) and that at 2 and 3 years was significantly increased (p < 0.001). LogMAR BCVA at 2 years postoperatively was significantly decreased compared with 1 month postoperatively (p = 0.008). Over the 3-year postoperative period, overall refractive predictability within ±1.00 D and ±0.50 D ranged from 69.0% to 86.2% and from 43.3% to 67.8%, respectively. This also decreased from 1 month to 6 months postoperatively (p < 0.005). Multivariate logistic regression analysis using generalized estimating equations, revealed that higher preoperative SE (odds ratio [OR], 2.58 and 7.23; p < 0.001) and lower preoperative BCVA (OR, 2.44; p = 0.003) were predictive of a low postoperative efficacy. In summary, myopic LASIK can be effective and safe with a high refractive predictability in a Korean population, but myopic regression occurs over time. Higher preoperative SE and lower preoperative BCVA are predictive of a low postoperative efficacy.

Comparison of effective corneal refractive centration to the visual axis: LASIK vs SMILE, a contralateral eye digitized comparison of the postoperative result.

To define and compare the centration of the ablation effect in laser in situ keratomileusis (LASIK) with the corresponding effect in small-incision lenticule extraction (SMILE), in myopic laser vision correction to possibly explain the refractive performance differences noted between the two procedures in a contralateral eye study. Private ambulatory eye surgery unit. Prospective randomized contralateral eye study. In 22 consecutive patients (44 eyes), 1 eye was prospectively randomized to undergo myopic topography-guided LASIK treatment and the contralateral eye to undergo SMILE; digital image analysis of the achieved centration to the aimed corneal vertex was assessed for both procedures on perioperative Scheimpflug tangential curvature maps, using a proprietary digitized methodology. The radial displacement measured in micrometers in the above treated 44 eyes, between the attempted centration point on the corneal vertex vs the center of the measured effective anterior corneal curvature flattening was on average 130 ± 62 mm in the 22 eyes of LASIK group and 313 ± 144 mm in the 22 contralateral eyes of the SMILE group (P < .001). In this contralateral eye study, topography-guided myopic LASIK was found to achieve significantly better effective centration compared with myopic SMILE, in regard to digitally measured decentration of the effective refractive change achieved in the anterior corneal curvature from the corneal vertex. This may explain the previously reported superior visual outcomes in the LASIK group eyes when compared with the contralateral SMILE group eyes.

Ray-tracing Calculation Using Scheimpflug Tomography of Diffractive Extended Depth of Focus IOLs Following Myopic LASIK.

To evaluate a ray-tracing formula for intraocular lens (IOL) calculation of diffractive extended depth of focus IOLs after myopic laser in situ keratomileusis (LASIK) compared to formulas from an established online calculator. This retrospective, consecutive case series included patients after cataract surgery with implantation of an extended depth of focus (EDOF) IOL (AT LARA, Carl Zeiss Meditec; Symfony, Johnson & Johnson) and a history of myopic LASIK. Preoperative assessments included biometry (IOLMaster; Carl Zeiss Meditec) and corneal tomography, including true net power (TNP) (Pentacam; Oculus Optikgeräte GmbH). To evaluate the measurements, the simulated keratometry values (SimK) were compared to the TNP. Regarding IOL calculation, the mean prediction error, mean and median absolute prediction error (MAE and MedAE), and number of eyes within ±0.50, ±1.00, and ±2.00 diopters (D) from the Haigis-L, Shammas, and Barrett True K No History formulas to the Potvin-Hill and Haigis with TNP (Pentacam) formulas were compared. Thirty-six eyes matched the inclusion criteria with a mean spherical equivalent of -6.26 ± 3.25 diopters (D) preoperatively and -0.79 ± 0.75 D postoperatively. The mean difference from SimK and TNP was significantly different from zero (P < .001; -1.24 ± 0.81 D). The best performing formulas by MedAE were the Potvin-Hill and Barrett True K No History (0.39 ± 0.78 and 0.64 ± 1.00 D). The formula with the most eyes within ±0.50 D was the Potvin-Hill (64%), followed by the Barrett True K No History (44%). For MAE and percentage of eyes within ±0.50 D, the Potvin-Hill formula was significantly better than the Haigis-L, Shammas, and Haigis-TNP formulas (P < .05). Calculation of IOLs in patients who had LASIK remains less predicable than calculations for virgin eyes. Using ray-tracing to calculate diffractive EDOF IOLs after myopic LASIK, the Potvin-Hill formula outperformed established formulas in terms of the percentage within target refraction and the MAE. [J Refract Surg. 2021;37(4):231-239.].

Evolution of corneal epithelial remodeling after myopic laser in situ keratomileusis surgery measured by anterior segment optical coherence tomography combined with Placido disk.

Purpose:To investigate patterns of short- and long-term variations in corneal epithelial thickness (CET) after myopic laser in situ keratomileusis (LASIK) using anterior segment optical coherence tomography (AS-OCT) combined with Placido disk-based topography.Methods:In this retrospective study, 36 subjects (72 eyes) who underwent LASIK myopic surgery and 53 healthy subjects (106 eyes) who served as controls were enrolled. AS-OCT (MS-39) was performed in all patients before, 1 day, 1 month, and 6 months after surgery. Statistical analysis was performed to analyze CET changes over time after LASIK and to detect patterns of definitive CET remodeling compared to healthy subjects. Multivariate analysis was performed to look for possible predictors of final CET.Results:There was no statistically significant difference between groups in terms of demographic and anterior segment parameters (all P > 0.05). After LASIK, all sectors and rings got thicker over time (1.62–8.32 μm; P < 0.01). Except for the central sector, all areas achieved the thickest CET value one day after surgery with a progressive epithelial thinning between 1 and 6 months of follow-up. Changes on CET occurred independently of the grade of myopia before LASIK or final refraction (P > 0.05). None of the clinical variables studied, including diopters corrected, were found to be correlated with final CET (P > 0.05).Conclusion:Independent of anterior segment parameters and diopters corrected, CET becomes thicker after LASIK surgery. Central and inner ring sectors thicken more than those more peripheral. CET remodeling after myopic LASIK should be taken into consideration when planning refractive surgery.

Wavefront-guided myopic laser in situ keratomileusis with a high-resolution Hartmann-Shack aberrometer and a new nomogram.

To evaluate visual, refractive, aberrometric, and patient-reported outcomes of wavefront-guided (WFG) myopic laser in situ keratomileusis (LASIK) using a high-resolution Hartmann-Shack aberrometer (iDesign Advanced WaveScan system) with a new nomogram and to determine whether the new nomogram resolved the mild undercorrection that occurs with the manufacturer's default settings. Three private LASIK practices. Prospective, open-label, noncomparative, multicenter study. One hundred ninety eyes of 95 patients underwent bilateral WFG LASIK for the correction of myopia or myopic astigmatism. A new nomogram was used, which effectively adjusted the wavefront-measured refraction sphere up or down to equal the manifest refraction sphere. Patients were followed up for 6 months. Eighty-four patients completed the final follow up. At 6 months, 162 (96.4%) of 168 eyes achieved monocular uncorrected distance visual acuity of 20/20 or better. No eye lost 2 or more lines of corrected distance visual acuity. The safety and efficacy indices were 1.12 and 1.09, respectively; 164 (98%) of 168 eyes had manifest refraction spherical equivalent within ±0.50 diopters (D) of emmetropia, and 154 (92%) of 168 eyes had residual manifest refractive astigmatism of 0.50 D or less. Fewer patients experienced burning, stinging, soreness, and irritation postoperatively than preoperatively. Eighty-one (96%) of 84 patients reported improved quality of life. WFG myopic LASIK using a high-resolution Hartmann-Shack aberrometer and a new nomogram resolved the undercorrection with the manufacturer's default settings. The treatment was safe and effective with excellent visual and refractive outcomes, high patient satisfaction, and improved quality of life.

Hyperopic shifts and anterior curvature flattening after Descemet-stripping endothelial keratoplasty and cataract surgery in 2 patients with a history of myopic LASIK

Two patients with a history of myopic laser in-situ keratomileusis (LASIK) experienced larger-than-expected hyperopic results after cataract surgery and Descemet-stripping endothelial keratoplasty (DSEK) for Fuchs endothelial corneal dystrophy. Although an anticipated hyperopic shift from DSEK-related posterior curvature steeping was taken into account during IOL power calculations, the refractive outcome was still more hyperopic than expected. Postoperative analysis revealed significant and unexpected flattening of the anterior corneal curvature that is not common after standard DSEK. Central anterior stromal ablation from myopic LASIK might make the cornea more prone to swelling and anterior steepening as Fuchs dystrophy progresses, increasing corneal power. A subsequent reduction in swelling might then cause central flattening and contribute to hyperopic errors after combined cataract–endothelial keratoplasty surgery.

Cataract surgery after myopic laser in situ keratomileusis: objective analysis to determine best formula and keratometry to use.

To objectively determine which formula/keratometry combination was best for calculating intraocular lens (IOL) sphere power in eyes with a history of myopic laser in situ keratomileusis (LASIK). One practice in the United States. Retrospective, unmasked, nonrandomized chart review. Consecutive patients undergoing cataract surgery after previous myopic LASIK were included. Eyes had to have a postoperative refraction at least 3 weeks postoperatively. IOL power was calculated with the ASCRS online postrefractive IOL calculator using anterior keratometry and recalculated using total corneal power (TK). The accuracy of treatment was calculated and compared between different formulas and keratometry methods including intraoperative aberrometry (IA). Data from 101 eyes, 44 of which had TK available, were analyzed. Using TK, the Wang-Koch-Maloney formula had the highest percentages of eyes with expected spherical equivalent refractive errors within 0.50 diopter (D) and 1.00 D of plano (57% and 87%, respectively). With anterior keratometry, the Barrett True-K formula had the highest percentages (64% and 92%, respectively) but was not significantly better than the Wang-Koch-Maloney formula, with expected errors within ±0.50 and ±1.00 D (P > .2, McNemar test). Expected sphere results based on IA were not significantly different than for Barrett True-K within ±0.50 D or within ±1.00 D (P > .2, McNemar test). Using TK in existing post-LASIK formulas did not seem beneficial. The formulas might have to be optimized for use with TK. The best expected results were obtained with the Barrett True-K and Haigis-L formulas using anterior keratometry. IA did not seem to materially improve results.