D. Obtain serum protein electrophoresis and immunofixation test
Refractory SRF with vitelliform material and absence of leakage on the angiogram (angiographic silence) prompted an investigation for an immunogammopathy (choice D). Continuing intravitreal anti-VEGF injections (choice A) is unlikely to be beneficial because the SRF was refractory to 32 anti-VEGF treatments, and lack of drusen suggest a diagnosis other than exudative age-related macular degeneration. Photodynamic therapy (choice B) is not recommended as the next step because choroidal atrophy and lack of leakage on the angiogram are not consistent with central serous chorioretinopathy. An electrooculogram and molecular genetic testing (choice C) is expected to be negative because a diagnosis of Best disease is improbable given the patient’s age at diagnosis.