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

Laser in Situ Keratomileusis Outcomes and Complications: 2016 to 2023

PURPOSE

To review current clinical outcomes, complications, and patient satisfaction of laser in situ keratomileusis (LASIK) from studies published between 2016 and 2023, with a specific focus on refractive outcomes and topography-guided LASIK (TG-LASIK).

METHODS

A literature review was conducted using PubMed and Scopus, identifying studies reporting LASIK outcomes, complications, and patient satisfaction. Inclusion criteria required studies to report aggregate clinical data, using validated metrics for subjective outcomes. Studies on re-treatment, specific corneal/systemic disorders, or follow-up shorter than 1 month were excluded. Separate analyses were performed for TG-LASIK and other LASIK treatments.

RESULTS

Ninety-five studies met the final inclusion criteria. Myopic treatment achieved better outcomes than hyperopic treatment, with 88.3% and 69.2% reaching an uncorrected distance visual acuity (UDVA) of 20/20, respectively. TG-LASIK demonstrated superior refractive outcomes to LASIK myopic treatment, with 91.8% having 20/20 or better UDVA, and 95% and 100% of eyes achieving refractive accuracy within ±0.50 and ±1.00 diopters, respectively. Complication rates were low, with the most common being flap folds (0.73%). Sight-threatening complications occurred in 0.07% of the eyes. Patient satisfaction remained high, with 92.6% reporting satisfaction with surgery, and 99% would recommend the procedure to a friend.

CONCLUSIONS

LASIK remains a safe, effective, and highly satisfying refractive surgery, with TG-LASIK demonstrating superior outcomes compared to other LASIK treatments. Complications were infrequent, and subjective visual symptoms generally improved postoperatively. Future research should use standardized methods for assessing and reporting subjective outcomes, including preoperative and postoperative comparisons, to provide a more comprehensive understanding of LASIK outcomes. [J Refract Surg. 2025;41(4):e391-e403.].

12-Month Visual and Refractive Outcomes of Topography-guided Femtosecond Laser-Assisted LASIK for Myopia and Myopic Astigmatism

PURPOSE

To report 12-month visual and refractive outcomes following topography-guided femtosecond laser-assisted laser in situ keratomileusis (LASIK) for myopia and compound myopic astigmatism correction.

METHODS

This prospective, single-center observational study was conducted in an outpatient clinical practice at the Stanford University Byers Eye Institute in Palo Alto, California. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity, 5% and 25% contrast sensitivity CDVA, and manifest refraction following topography-guided femtosecond laser-assisted LASIK were assessed. Refractive measurements were used to perform a vector analysis.

RESULTS

Sixty eyes of 30 patients (mean age: 32.8 ± 7.0 years; range: 23 to 52 years) undergoing topography-guided LASIK for the correction of myopia and compound myopic astigmatism were analyzed. Mean postoperative UDVA was -0.09 ± 0.10 logarithm of the minimum angle of resolution (logMAR) at 12 months. Mean preoperative CDVA was -0.09 ± 0.09 and -0.13 ± 0.08 logMAR at postoperative 12 months. At 12 months, 26.9% of eyes had gained one or more lines of postoperative UDVA compared to baseline CDVA. Mean pre-operative 5% contrast sensitivity CDVA was 0.68 ± 0.07 and 0.64 ± 0.12 logMAR at 12 months (P = .014) following LASIK.

CONCLUSIONS

Topography-guided LASIK for myopia and myopic astigmatism correction provided excellent visual and refractive outcomes that were predictable, precise, and stable up to 12 months postoperatively. [J Refract Surg. 2024;40(9):e595-e603.].

Corneal Epithelial Thickness Mapping: A Major Review

The corneal epithelium (CE) is the outermost layer of the cornea with constant turnover, relative stability, remarkable plasticity, and compensatory properties to mask alterations in the underlying stroma. The advent of quantitative imaging modalities capable of producing epithelial thickness mapping (ETM) has made it possible to characterize better the different patterns of epithelial remodeling. In this comprehensive synthesis, we reviewed all available data on ETM with different methods, including very high-frequency ultrasound (VHF-US) and spectral-domain optical coherence tomography (SD-OCT) in normal individuals, corneal or systemic diseases, and corneal surgical scenarios. We excluded OCT studies that manually measured the corneal epithelial thickness (CET) (e.g., by digital calipers) or the CE (e.g., by confocal scanning or handheld pachymeters). A comparison of different CET measuring technologies and devices capable of producing thickness maps is provided. Normative data on CET and the possible effects of gender, aging, diurnal changes, refraction, and intraocular pressure are discussed. We also reviewed ETM data in several corneal disorders, including keratoconus, corneal dystrophies, recurrent epithelial erosion, herpes keratitis, keratoplasty, bullous keratopathy, carcinoma in situ, pterygium, and limbal stem cell deficiency. The available data on the potential role of ETM in indicating refractive surgeries, planning the procedure, and assessing postoperative changes are reviewed. Alterations in ETM in systemic and ocular conditions such as eyelid abnormalities and dry eye disease and the effects of contact lenses, topical medications, and cataract surgery on the ETM profile are discussed.