Electrolysis for corneal opacities in a young patient with superficial variant of granular corneal dystrophy (Reis-Bücklers corneal dystrophy)

Corneal Electrolysis for Granular Corneal Dystrophy Type 2 (Avellino Corneal Dystrophy) Exacerbation After LASIK

PURPOSE

To report two cases in which exacerbation of granular corneal dystrophy type 2 (GCD2; Avellino corneal dystrophy) after laser in situ keratomileusis (LASIK) was successfully removed by corneal electrolysis.

METHODS

This study involved a 66-year-old man and a 43-year-old man with GCD2 who had undergone bilateral LASIK for myopia 10 or more years prior to presentation. In both patients, GCD2 corneal opacity gradually developed postoperatively at the LASIK flap interface, thus resulting in a decrease of visual acuity. For treatment, the LASIK flaps in both patients were surgically lifted to directly remove the opacity. Corneal electrolysis was then applied to the back of each LASIK flap and stromal bed.

RESULTS

Postoperatively, the ocular symptoms and corneal opacities related to GCD exacerbation disappeared, with improvement of corrected and uncorrected distance visual acuity and almost no change of refractive error.

CONCLUSIONS

The findings reveal that corneal electrolysis is safe and effective for treating exacerbations of GCD2 following LASIK when applied to a surgically lifted flap, and that it successfully removes GCD2-related LASIK flap interface opacities with almost no change of refractive error postoperatively. [J Refract Surg. 2023;39(1):61-65.].

Clinical Evaluation of Electrolysis for Reis-Bücklers Corneal Dystrophies and In Vivo Histological Analysis Using Anterior Segment Optical Coherence Tomography

PURPOSE

To report the effectiveness and clinical outcomes of corneal electrolysis for Reis-Bücklers corneal dystrophies (RBCDs) and provide in vivo histological analysis using anterior segment optical coherence tomography (AS-OCT).

METHODS

A total of 7 patients with RBCD (2 male patients, 5 female patients; mean age, 50.0 years) from 3 pedigrees were enrolled in this prospective study. All patients underwent corneal electrolysis for decreased visual acuity or blurred vision. Changes in visual acuity, refraction, and corneal thickness were evaluated 1 month after electrolysis and statistically analyzed. Changes observed in AS-OCT images before and after electrolysis were qualitatively and quantitatively assessed.

RESULTS

A total of 22 electrolysis procedures were performed on 7 patients during the median follow-up period of 10.7 years. Mean visual acuity significantly improved postoperatively, from 0.59 to 0.31 logarithm of the minimum angle of resolution (P = 0.013). Changes in refraction (from -2.42 to -2.12 D) and corneal thickness (from 570.8 to 577.6 μm) were not significant (P = 0.77 and P = 0.80, respectively). In all cases, assessment of AS-OCT images showed that the band lesion in Bowman's layer became less reflective after electrolysis. The mean thickness of the band lesion decreased from 101.5 to 88.3 μm (P = 0.002).

CONCLUSIONS

Corneal electrolysis is an excellent treatment option for corneal opacities caused by RBCD. Corneal electrolysis improves visual acuity without changing corneal thickness or refraction. Therefore, repeat corneal electrolysis over the years might be a preferred long-term treatment strategy for RBCD. Moreover, AS-OCT is suitable for evaluating the effectiveness of this treatment and might be useful during postoperative follow-up.

Pathogenesis and treatments of TGFBI corneal dystrophies

Transforming growth factor beta-induced (TGFBI) corneal dystrophies are a group of inherited progressive corneal diseases. Accumulation of transforming growth factor beta-induced protein (TGFBIp) is involved in the pathogenesis of TGFBI corneal dystrophies; however, the exact molecular mechanisms are not fully elucidated. In this review article, we summarize the current knowledge of TGFBI corneal dystrophies including clinical manifestations, epidemiology, most common and recently reported associated mutations for each disease, and treatment modalities. We review our current understanding of the molecular mechanisms of granular corneal dystrophy type 2 (GCD2) and studies of other TGFBI corneal dystrophies. In GCD2 corneal fibroblasts, alterations of morphological characteristics of corneal fibroblasts, increased susceptibility to intracellular oxidative stress, dysfunctional and fragmented mitochondria, defective autophagy, and alterations of cell cycle were observed. Other studies of mutated TGFBIp show changes in conformational structure, stability and proteolytic properties in lattice and granular corneal dystrophies. Future research should be directed toward elucidation of the biochemical mechanism of deposit formation, the relationship between the mutated TGFBIp and the other materials in the extracellular matrix, and the development of gene therapy and pharmaceutical agents.

A novel phenotype-genotype correlation with an Arg555Trp mutation of TGFBI gene in Thiel-Behnke corneal dystrophy in a Chinese pedigree

Background

To investigate the molecular defects in a four-generation Chinese pedigree affected with Thiel-Behnke corneal dystrophy (TBCD). And to further study the relationship between genetic mutation and clinical manifestations.

Methods

Individuals of the pedigree were recruited for extensive ophthalmic examinations. Histological studies of two corneal buttons obtained from lamellar keratoplasty were conducted. Peripheral blood was collected in EDTA for genomic DNA isolation from leukocytes of all affected and unaffected members. All 17 exons of the TGFBI gene were screened for mutations by polymerase chain reaction and direct DNA sequencing.

Results

Clinical examinations revealed a typical pattern of honeycomb-like TBCD. Histopathology study demonstrated eosinophilic deposits that were congo-red-positive and did not stain with periodic acid Schiff or Masson’s trichrome. Genetic analysis disclosed a heterozygous p. Arg555Trp mutation resulted from a missense c. 1663C > T nucleotide change in exon 12 of TGFBI gene in all affected members. Morever, a second rare variant in exon 6 of the TGFBI gene (p. Arg257Trp) also cosegregated within this family and has been confirmed to be a single nucleotide polymorphism (SNP) not previously reported.

Conclusions

The p. Arg555Trp mutation of the TGFBI gene was associated with TBCD, which revealed a novel phenotype-genotype correlation within the mutational spectrum of phenotypically diverse corneal dystrophies.