Reviewed by Pallak Kusumgar, MS
Findings of a study associating the preoperative gene expression of certain molecular factors in corneal epithelial tissue and tears of keratoconus (KCN) patients with outcomes of corneal crosslinking (CXL) point to the possibility of developing an assay for predicting CXL response and complications.
“Our study suggests that the outcome of CXL may be determined by the levels of basal inflammation, collagen, and cellular components,” said Pallak Kusumgar, MS, Cornea, Cataract, and Refractive surgery fellow, Narayana Nethralaya Eye Hospital, Bangalore, India.
“Now our aim is to apply the results from this study and ongoing research to develop a rapid point-of-care kit for detecting predictive biomarkers in preoperative tears,” Kusumgar said. “Such an assay could provide evidence-based prognostication and customized treatment selection for improved patient outcomes.”
To investigate associations between molecular markers and CXL outcomes, Kusumgar and colleagues undertook a prospective study enrolling patients with progressive keratoconus. Eligible eyes had grade 1 or 2 keratoconus with >1 D increase in keratometry in the previous 6 months, corneal thickness ≥400 μm at the thinnest location, and contact lens intolerance, Kusumgar noted.
Patients with active allergic eye disease or ocular inflammation, central or paracentral scarring, or other ocular comorbidities were excluded.
Samples from the corneal epithelium over the ectatic cone area and the corneal periphery were obtained pre-operatively from KC patients when performing accelerated CXL. The tissue samples were analyzed for total mRNA levels of lysyl oxidase (LOX), matrix metalloproteinase 9 (MMP 9), bone morphogenic protein 7 (BMP7), tissue inhibitor of metalloproteinase 1 (TIMP1), and two collagens [collagen type I, alpha 1 (COL 1A1 and collagen type IV, alpha 1 (COL IVA1)].
Patients were followed for at least 6 months and categorized as achieving an optimal or suboptimal response defined by whether or not they had a ≥0.5 D decrease from the preCXL maximum keratometry (Kmax).
Pallak Kusumgar, MS
E: [email protected]
This article was adapted from a presentation at the 2018 meeting of the American Society of Cataract and Refractive Surgery. A paper reporting on data from 35 eyes in the series has been published [Shetty R, et al. Cornea. 2018;37:369-374]. Kusumgar has no relevant fi nancial interests to disclose.