To investigate the relationship between subfoveal choroidal thickness and metabolic activity in eyes with choroidal melanoma.

Retrospective, interventional case series.

The medical records of 16 patients with unilateral choroidal melanoma who underwent ruthenium (Ru) 106 brachytherapy with adjuvant transpupillary thermotherapy and who had available pretreatment positron emission tomography–computed tomography (PET-CT) images were retrospectively reviewed. Subfoveal choroidal thickness was measured in tumor eyes and in unaffected fellow eyes using enhanced-depth imaging spectral-domain optical coherence tomography (EDI OCT). Tumor eyes were divided into 2 groups (metabolically active and inactive) based on PET-CT findings and subfoveal choroidal thickness was compared between groups. Additionally, choroidal thickness measurements were compared before and after treatment.

Before treatment, mean choroidal thickness was 293.31 ± 46.80 μm in tumor eyes and 242.44 ± 65.37 μm in fellow eyes, a difference that was statistically significant (P = .003). Eyes with metabolically active tumors had a significantly thicker choroid (348.00 ± 17.32 μm) than eyes with metabolically inactive tumors (280.69 ± 42.04 μm, P = .019). In tumor eyes, mean choroidal thickness significantly decreased from pretreatment values to 253.56 ± 61.27 μm 6 months after treatment (P = .018).

Eyes with choroidal melanoma had thicker choroids than unaffected fellow eyes. Increased choroidal thickness was more prominent in metabolically active tumors. Choroidal thickness significantly decreased in tumor eyes 6 months after treatment.