Choroidal Nevus Features Associated with Subspecialty Referral

Objective: To identify choroidal nevus features associated with referral to a retina or ocular oncology subspecialist.Design: Population-based retrospective cohort study.Subjects: Patients diagnosed with choroidal nevus.Methods: Population-based retrospective cohort study of residents of Olmsted County, Minnesota, with an incident diagnosis of choroidal nevus from January 1, 2006, to December 31, 2015 using the Rochester Epidemiology Project, a medical record linkage system. Tumor features and patient demographics associated with referral to a retina or ocular oncology subspecialist were assessed. Wilcoxon rank sum test, chi-square test, and Fisher exact test were used for statistical analysis.Main outcome measures: Tumor features and patient demographics associated with referral to subspecialty care.Results: There were 826 incident diagnoses of choroidal nevus, of which 88 cases (11%) were referred, with highest level of referral being retina in 29 cases (33%) and ocular oncology in 59 cases (67%). None of the analyzed demographic features were associated with choroidal nevus referral to subspecialty care. Tumor features associated with referral (vs. not referred) included greater mean basal diameter (4.6 mm vs. 2.4 mm, P < 0.001), greater mean tumor thickness (0.7 mm vs. 0.1 mm, P < 0.001), greater distance to optic disc (6.9 mm vs. 3.4 mm, P = 0.02), halo around nevus (5.7% vs. 0.4%, P < 0.001), and drusen on OCT (51% vs. 25%, P = 0.002). Presence of orange pigment (8% vs. 0%, P = 0.14), subretinal fluid (9% vs. 2.5%, P = 0.09), and low internal reflectivity on A-scan (7.7% vs. 0%, P = 1.00) were not found more frequently in the subspecialty referral group.Conclusions: Greater basal diameter and mean tumor thickness of choroidal nevus were associated with referral to retina or ocular oncology. However, several features associated with increased risk of malignant transformation were not associated with subspecialty referral. These findings highlight the importance of educating eye care providers about high-risk tumor features associated with choroidal nevus transformation to melanoma. In the primary eye care setting where not all multimodal imaging may be available, we encourage color photography and OCT with referral for any features of basal diameter > 5 mm, presence of subretinal fluid, or thickness too large for capture by enhanced-depth imaging OCT.