Purpose: To determine the morphologic features (grade and type) of posterior staphylomas and to analyze the relationship between the morphologic features and the incidence of myopic macular lesions.
Design: Observational case series.
Methods: Two hundred and nine eyes of 108 consecutive patients with high myopia were studied. The grade of staphylomas was determined from B-scan ultrasonographic images across the optic disk. The type of staphyloma was determined by binocular funduscopy and was classified according to the criteria of Curtin. The participants were divided into two groups: younger than 50 years and 50 years and older. The long-term morphologic progression of staphylomas was analyzed in nine patients who were followed up for more than 20 years.
Results: Ninety percent of 209 eyes had a staphyloma. The prevalence of staphylomas and more advanced grades of staphylomas (> grade 2) were significantly higher in the older than in the younger patients. The higher grades of staphylomas were associated with more severe myopic retinal degeneration. Type II staphyloma was the most prominent overall; however, in older subjects, the incidence of type II was decreased significantly, and that of type IX was increased significantly. The eyes with type IX staphyloma tended to have more severe myopic retinal degeneration than eyes with type II staphylomas. The long-term follow-up study demonstrated a progression from type II to type IX with increasing age.
Conclusions: These results suggest that the morphologic features of staphylomas worsens as the patient ages. The progression from type II to type IX probably increases the mechanical tension on the macular area of highly myopic eyes, which then leads to myopic fundus lesions.