Ocular surface and anterior segment changes in cystic fibrosis: evidence of a corneal and conjunctival epithelial...

To characterize anterior segment structural alterations in adults with cystic fibrosis (CF), with emphasis on conjunctival and corneal epithelial parameters, and to compare them with healthy controls.

This cross-sectional study included 33 adults with CF and 33 age- and sex-matched controls. Swept-source OCT was used to quantify bulbar conjunctival thickness (BCT) and bulbar conjunctival epithelial thickness (BCEpT) in four quadrants, as well as central corneal epithelial thickness (CEpT) and central corneal thickness (CCT). Keratometry and non-invasive TBUT (N-TBUT) were assessed using the Topcon MYAH multifunctional device. Endothelial parameters were evaluated with specular microscopy, and symptoms were recorded with the OSDI questionnaire.

CF patients exhibited significant BCEpT thinning across all quadrants (all p < 0.001) and selective temporal BCT thinning (p < 0.05). CEpT was significantly reduced (p < 0.010), while CCT remained comparable between groups (p > 0.100). Keratometric values (K1, K2) were steeper in CF (p < 0.05). N-TBUT was preserved mainly, although CF individuals reported higher OSDI scores (p < 0.01). Endothelial cell density and morphology showed no between-group differences (all p > 0.100). No significant correlations were found between ocular structural parameters and lung function indices.

CF is associated with a distinct epithelial phenotype characterized by thinning of both conjunctival and corneal epithelium and steeper anterior corneal curvature, while stromal and endothelial layers remain preserved. These findings indicate preferential involvement of CFTR-dependent epithelial tissues and suggest early, subclinical ocular surface alterations in CF.