Higher subfoveal choroidal thickness in choroidal melanomas than in choroidal nevi.

To compare subfoveal choroidal thickness (SFCT) between eyes with choroidal melanoma and choroidal nevi. Retrospective study of 126 consecutive patients in a tertiary ocular oncology center. Eyes with tumors located less than two disc-diameters from the fovea were excluded. In eyes with naevi, factors of potential transformation into melanoma were recorded (orange pigment, subretinal fluid, thickness >2 mm, diameter >5 mm, ultrasound hollowness). SFCT was assessed by 3 independent observers on horizontal spectral-domain OCT scans. Sixty-seven eyes with choroidal melanoma and 59 eyes with choroidal nevi were included. The melanoma and nevi groups did not differ in gender (P=0.14) nor age (P=0.34). There was a very good agreement between the three independent observers for SFCT measurements (intraclass correlation coefficient=0.89). Mean SFCT was higher in melanomas (294.3±89.9 µm) than naevi (260.3±76.7 µm) (P=0.013), and the difference remained significant between melanomas and 28 naevi with ≥2 growth risk factors (256.3±77.0 µm) (P=0.027). In a multivariate model, the significant contributors to SFCT were presence of melanoma (P=0.004), younger age (P<0.0001) and shorter lesion distance to the fovea (P=0.016). SFCT may reflect the interplay between melanocytic tumors and their choroidal microenvironment. Its clinical utility should be explored in future studies.