Prevalence and clinical correlates of focal choroidal excavation in a large cohort of Chinese patients with choroidal osteoma

Purpose To describe the prevalence and clinical characteristics of focal choroidal excavation (FCE) in a large cohort of Chinese patients with choroidal osteoma (CO). Methods One hundred and thirty-two eyes of 110 Chinese patients diagnosed with CO were enrolled. The prevalence and clinical characteristics of FCE were studied. Univariate and multivariate linear regression analyses were used to identify the factors associated with the occurrence of FCE. Furthermore, FCEs were divided into two types based on their location: Type 1 (at the edge of the tumor) and Type 2 (inside the tumor), and their clinical features were analyzed. Results The prevalence of FCE was 46.2% in 132 eyes with CO. Eyes with FCEs demonstrated a longer disease duration ( P < 0.01), worse BCVA ( P = 0.01), longer greatest tumor linear dimension ( P < 0.01), larger total tumor area ( P < 0.01) and decalcification area ( P < 0.01), and a higher incidence of outer retinal tubulation (ORT) ( P = 0.01). Only disease duration ( P = 0.025) was significantly correlated with the occurrence of FCE. Patients with Type 2 FCEs had a larger greatest linear dimension of FCEs and a higher likelihood of ORT, choroidal neovascularization, disruption of the external limiting membrane, and inner retina compared with those with Type 1 FCEs (all P < 0.05). Conclusions The duration is associated with the development of FCE in CO. The different types of FCE may indicate varying stages of CO, suggesting the occurrence and enlargement of FCE in CO are associated with the lateral expansive growth of the tumor. Comprehensive optical coherence tomography evaluation of tumor margins and extramacular regions during initial assessment and regular follow-up is recommended to enable early FCE detection (particularly Type 2), allowing timely identification of CNV and other complications for prompt vision-preserving intervention.