The height of the posterior staphyloma and corneal hysteresis is associated with the scleral thickness at the staphyloma region in highly myopic normal-tension glaucoma eyes

Aims: To evaluate the characteristics of the posterior segments of eyes with high myopia and normal-tension glaucoma (NTG) and identify which ocular factors are most associated with scleral thickness and posterior staphyloma height. Methods: The study included 45 patients with highly myopic NTG and 38 controls with highly myopic eyes (≤-6D or axial length ≥26.0 mm). The subfoveal retinal, choroidal, scleral thickness and the posterior staphyloma heights were examined from enhanced depth imaging spectral-domain optical coherence tomography and compared between two groups. Results: Highly myopic NTG eyes had thinner subfoveal scleral thickness (473.03±43.75 vs 579.46±75.87 μm, p<0.001) and higher posterior staphyloma (97.80±70.10 vs 62.83±32.01 μm, p=0.027) than highly myopic, non-glaucomatous eyes. Subfoveal scleral thickness was significantly correlated with age, axial length, corneal hysteresis and the posterior staphyloma height of the superior quadrant, the nasal quadrant and the arithmetic mean of four quadrants in highly myopic NTG eyes. Corneal hysteresis (β=2.694, p=0.015), corneal resistance factor (β=-2.916, p=0.010) and the posterior staphyloma height of the nasal quadrant (β=-0.463, p=0.017) were significantly associated with the subfoveal scleral thickness in highly myopic NTG eyes. Conclusion: Subfoveal scleral thinning and non-uniform posterior staphyloma were closely related in highly myopic NTG eyes. Corneal hysteresis, corneal resistance factor and the nasal posterior staphyloma height were associated with the scleral thickness.