Purpose:
To report a case of bilateral and repetitive corneal perforations after corneal cross-linking (CXL) for keratoconus in a woman harboring potentially pathogenic variants in the ZNF469 gene and to characterize the keratoconus phenotype in this woman and her daughter who shared the same ZNF469 mutations.
Methods:
Clinical characterization of the proband and her daughter followed by sequencing of the genes associated with brittle cornea syndrome, ZNF469 and PRDM5, in both individuals.
Results:
An Ashkenazi Jewish woman in her sixth decade presented with diffuse corneal thinning and progressive steepening consistent with keratoconus. After CXL, epithelium-off in the first eye and epithelium-on in the second, she developed spontaneous corneal perforations in each eye. Her daughter in her fourth decade demonstrated a similar pattern of diffuse corneal thinning and progressive corneal steepening but did not undergo CXL and did not develop corneal perforation. Screening of the ZNF469 and PRDM5 genes revealed 3 missense ZNF469 variants (c.2035G>A, c.10244G>C, and c.11119A>G) in cis arrangement on 1 allele of ZNF469 in both proband and her daughter. Although the 3 variants share low (<0.01) global minor allele frequencies, each has significantly higher minor allele frequencies (0.01–0.03) in the Ashkenazi Jewish population, leading to uncertainty regarding a pathogenic role for the identified variants.
Conclusions:
CXL may be associated with the development of corneal perforation in particular at-risk individuals with keratoconus. Identifying clinical and genetic risk factors, including screening of ZNF469 and PRDM5, may be useful in the prevention of significant complications after CXL.
PURPOSE
To compare the visual, refractive, keratometric, topographic, and pachymetric outcomes of corneal collagen cross-linking (CXL) for progressive keratoconus following epithelial removal by transepithelial phototherapeutic keratectomy (PTK) or manual debridement.
METHODS
In this analysis, 339 eyes (78% male, 22% female) that had undergone CXL following manual epithelial debridement (n = 180) or ablation via PTK (n = 159) were evaluated preoperatively and at 6, 12, and 24 months postoperatively for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), maximum corneal keratometry, pachymetry, and spherical equivalent. The data were analyzed in a t test to evaluate the relative efficacy of each epithelial removal procedure.
RESULTS
Manual epithelial debridement and ablation via PTK produce equivalent changes for all variables at each time interval with the exception of maximum corneal keratometry at 6 months postoperatively, for which PTK exhibited a significantly improved (flatter) result. This difference was present but not statistically significant at 12 and 24 months postoperatively.
CONCLUSIONS
Prior to CXL, both manual epithelial debridement and ablation via PTK result in equivalent visual, refractive, and keratometric outcomes up to 24 months postoperatively.
A prospective multiyear trial of 230 adolescent eyes with progressive keratoconus treated with CXL demonstrates safety and efficacy of treatment for slowing or halting disease progression and improving visual acuity.
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