Quantitative Evaluations of Posterior Staphylomas in Highly Myopic Eyes by Ultra-Widefield Optical Coherence Tomography

PURPOSE: To determine the shape of posterior staphylomas using ultra-widefield optical coherence tomographic (UWF-OCT) images and to identify the factors contributing to the shape and grade of the staphylomas in eyes with pathologic myopia. METHODS: This was an observational case series study. Highly myopic patients who were ≥40 years old with wide or narrow type of macular staphylomas were studied. High myopia was defined as a myopic refractive error (spherical equivalent) greater than −8.0 diopters (D) or an axial length (AL) > 26.5 mm. The maximum diameter and depth of the staphylomas were measured in the 12 radial scans of UWF-OCT images by ImageJ software and were compared between the two types of staphylomas. RESULTS: We studied 197 eyes of 138 patients with a mean age of 64.7 ± 10.4 years and mean AL of 30.0 ± 1.9 mm. The AL was significantly longer in the eyes with the narrow type than the wide type of staphyloma (P = 0.036). Multiple regression analyses showed that age was significantly correlated with the maximum depth/maximum diameter ratio (wide type, P < 0.001; narrow type, P = 0.003) of both types of staphylomas. The AL was significantly correlated with the depth/diameter ratio of only the narrow type of staphylomas (P = 0.005). CONCLUSIONS: The significant correlations of age and AL with the wide and narrow types of posterior staphylomas indicate that the factors for their formations may be distinctly different. Quantitative analyses of UWF-OCT images are helpful in determining the shape of the staphylomas.