Distinct Morphological Progression Patterns in Primary Versus Recurrent Pterygium: Vertical Attenuation Versus Deep...

To compare progression patterns between primary and recurrent pterygium using quantitative imaging.

This retrospective cohort study included 114 primary and 24 recurrent pterygium eyes. Clinical severity was assessed via T grade, V grade, and loss of vertical length of plica semilunaris (LPS). Morphological parameters, including horizontal invasion length (HIL), height, thickness, and the residual corneal thickness to central corneal thickness (RCT/CCT) ratio, were measured using anterior segment swept-source optical coherence tomography. Clinical severity and HIL-adjusted morphological parameters were compared, and correlation analyses assessed structural progression.

Recurrent pterygia exhibited higher clinical severity (T3 and V3 grades, P < 0.001) and greater LPS (P < 0.001). After adjusting for HIL, recurrent cases showed lower height (P = 0.048) and thickness (P = 0.012) compared to primary cases. In primary pterygium, HIL negatively correlated with height (r = -0.478, P < 0.001), thickness (r = -0.191, P = 0.042), and the RCT/CCT ratio (r = -0.483, P < 0.001), suggesting a pattern of "vertical attenuation." Conversely, in recurrent pterygium, HIL demonstrated a much stronger negative correlation with the RCT/CCT ratio (r = -0.704, P < 0.001) but no correlation with height, indicating a pattern of "deep stromal invasion".

Primary pterygium demonstrates an association consistent with vertical attenuation, whereas recurrent pterygium exhibits a structural pattern consistent with deep stromal invasion while maintaining its vertical bulk.

Characterizing the distinct pathways provides an objective basis for tailored surgical planning and optimized patient care strategies.