Laser refractive surgery in corneal dystrophies

Clinical and Optical Coherence Tomography Correlation of Recurrence Patterns After Femtosecond Laser-Assisted Anterior Lamellar Keratoplasty in Reis-Bucklers Corneal Dystrophy

PURPOSE

The aim of this study was to report the clinical profile and patterns of recurrence after femtosecond laser-assisted anterior lamellar keratoplasty (FALK) in Reis-Bucklers corneal dystrophy.

METHODS

This is a case series of 5 eyes of 4 patients with Reis-Bucklers corneal dystrophy. Clinical images of recurrence were correlated with the high-resolution optical coherence tomography. Histopathologic examination of excised corneal samples was performed when possible.

RESULTS

The median time to recurrence was 2 (1-5) years after FALK. Of the 5 eyes, 1 eye had primary FALK, whereas 4 eyes had secondary interventions, which included previous phototherapeutic keratectomy (once in 1 eye and twice in 2 eyes), and previous penetrating keratoplasty, followed by phototherapeutic keratectomy (1 eye). Recurrence was noted at the level of the subepithelium. In addition, 1 eye showed interface deposits along with epithelial downgrowth at the graft-host bed.

CONCLUSIONS

The 2 distinct patterns of recurrence noted were at the subepithelial region and the interface. The clinical patterns of recurrence favor an epithelial origin of recurrent deposits.

Management of Corneal Haze After Photorefractive Keratectomy

Photorefractive keratectomy (PRK) is a safe and popular corneal surgery performed worldwide. Nevertheless, there is potential risk of corneal haze development after surgery. Proper management of post PRK haze is important for good visual outcome. We performed a comprehensive review of the literature on the various risk factors and treatments for PRK haze, searching the PubMed, Google Scholar, SCOPUS, ScienceDirect, and Embase databases using relevant search terms. All articles in English from August 1989 through April 2023 were reviewed for this study, among which 102 articles were chosen to be included in the study. Depending on the characteristics of and examination findings on post PRK haze, different management options may be preferred. In the proposed framework, management of PRK haze should include a full workup that includes patient's subjective complaints and loss of vision as well as visual acuity, biomicroscopy, anterior segment optical coherence tomography, epithelial mapping, and Scheimpflug densitometry. Topical steroid treatment for haze should be stratified based on early- or late-onset haze. Mechanical debridement or superficial phototherapeutic keratectomy (PTK) may be used to treat superficial corneal haze. Deep PTK and/or PRK can be used to treat deep corneal haze. Mitomycin-C and topical steroids are prophylactic post-surgery agents to prevent recurrence of haze.

Update on contraindications in laser corneal refractive surgery

More than 25 years of experience with refractive surgery techniques (since the FDA [Food and Drug Administration] of the United States approved the use of the excimer laser in the remodeling of the cornea in 1995), added to the technological advances in ophthalmology (femtosecond laser, topography-guided ablation, anterior segment imaging systems) and increased understanding of refractive errors, higher order aberrations, and corneal biomechanics make corneal laser refractive surgery a safe method and effective for the correction of these defects. However, to date, there are still certain circumstances that represent a contraindication for its application, in addition to others that could be associated with complications, and that must be carefully analyzed. This review analyzes the current contraindications for laser corneal refractive surgery listed in the Preferred Practice Protocols (PPPs) of the American Academy of Ophthalmology and the Spanish Ophthalmology Society. These protocols are based on the best scientific evidence currently available and allow clear recommendations to be drawn, improving the safety profile of these techniques. Contraindications can be differentiated into relative or absolute; among the latter are: age less than 18 years, the absence of refractive stability and the existence of certain ocular pathologies (including certain corneal dystrophies, keratoconus, poorly controlled dry eye) or systemic pathologies (active autoimmune processes or poorly controlled diabetes mellitus). Other circumstances such as the use of certain drugs (amiodarone, isotretinoin), extreme values of mean central keratometry and pachymetry, history of previous uveitis or glaucoma, pregnancy and lactation, are considered relative contraindications according to the PPPs. However, there are studies that demonstrate the safety of refractive surgery in some of these cases.

Clearing the Haze: Navigating Corneal Refractive Surgery in Patients with Posterior Polymorphous Corneal Dystrophy

Posterior polymorphous corneal dystrophy (PPCD) is a corneal disorder of the endothelium and Descemet’s membrane. Although reports of corneal refractive surgery including laser-assisted in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE) in PPCD are minimal, these procedures have been shown to be safe and effective in this patient population. Proceeding with corneal refractive surgery in eyes with PPCD raises concerns regarding corneal integrity, including long-term biomechanical instability, risk of ectasia, endothelial cell loss, disease progression, and corneal decompensation. Thus, LASIK, PRK, and SMILE should be considered with caution. This commentary explores the patient characteristics associated with favorable surgical outcomes and factors that weigh against proceeding with refractive surgery.