Fundus Curvature as a Clinical Marker for Posterior Staphyloma Based on Widefield Optical Coherence Tomography

Purpose

To investigate the ability to quantify fundus curvature and detect posterior staphyloma using widefield optical coherence tomography (OCT).

Design

Cross-sectional diagnostic evaluation.

Methods

This study reviewed 205 highly myopic eyes of 205 participants. The Gaussian curvature map of the fundus was automatically calculated from 2 million scan points over an area of 24 mm × 20 mm, visualizing localized deformations in the posterior region. Two fovea-centered areas were designated as follows: a 6 mm × 6 mm macular region and an 8 mm × 16 mm posterior region. Macular mean curvature, macular curvature deviation, posterior mean curvature, posterior curvature deviation (PCD), and maximum posterior curvature were calculated. The relationship between curvature indices, ocular parameters, and myopic complications was investigated. The diagnostic ability of curvature indices for posterior staphyloma was evaluated.

Results

The mean (SD) age of 205 participants was 34.06 (12.74) years, with 107 being female (52.2%). Posterior staphyloma was found in 33 of 205 (16.1%) eyes. The curvature value map and curvature deviation map revealed detailed morphologic patterns of posterior staphyloma. Eyes with staphyloma had a steeper and more irregular fundus than eyes without staphyloma, with a larger maximum posterior curvature (20.420 × 10^–3 mm^–2 vs 10.925 × 10^–3 mm^–2, P < .001), posterior mean curvature (6.754 × 10^–3 mm^–2 vs 5.352 × 10^–3 mm^–2, P = .002), macular curvature deviation (1.889 × 10^–3 mm^–2 vs 1.078 × 10^–3 mm^–2, P < .001), and PCD (3.894 × 10^–3 mm^–2 vs 1.683 × 10^–3 mm^–2, P < .001). However, no difference in macular mean curvature was found between eyes with and without posterior staphyloma. Larger maximum posterior curvature, macular curvature deviation, and PCD were associated with greater degrees of myopia, more severe myopic maculopathy, and worse best-corrected visual acuity (all P < .05). PCD demonstrated the ability to discriminate the presence of posterior staphyloma (area under the curve 0.909 [95% CI 0.854-0.963; P < .001]). The optimal cutoff value of PCD was 3.060 × 10^–3 mm^–2 (Youden index = 0.725), with a specificity of 90.7% and a sensitivity of 81.8%.

Conclusion

Widefield OCT-based analysis of fundus curvature enhances detection and quantitative assessment of posterior staphyloma in high myopia.