Morphometric characterisation of pterygium associated with corneal stromal scarring using high-resolution anterior segment optical coherence tomography

Aims To investigate the role of high-resolution anterior segment optical coherence tomography (HR-ASOCT) in the assessment of pterygia. Methods Single centre cross-sectional study. Patients with primary pterygium and/or pingueculae were included. Clinical assessment included HR-ASOCT, colour photography, keratometry followed by histology. Associations were tested between HR-ASOCT features of the pterygium and the degree of corneal scarring and elastotic degeneration, astigmatism and best-corrected visual acuity. Results 29 eyes of 26 patients with pterygium and 6 patients with pinguecula were included. Apical anterior stromal scarring was found in 23 cases (79.3%) reaching a mean depth of 68.8±21.7 μm (minimum: 33 μm, maximum: 126 μm). Increased stromal scarring and subepithelial elastotic degenerative tissue was significantly associated with HR-ASOCT features of flat bridging of the corneoscleral transition zone (p<0.01) reduced thickness of the pterygium head (p=0.01), and a greater degree of corneal astigmatism (p=0.04). Conclusions HR-ASOCT is a useful tool for the assessment and monitoring of pterygia in clinical practice. Features associated with increased stromal scarring and astigmatism are reduced thickness of the head of the pterygium and flat bridging of the corneoscleral transition zone.