Tamoxifen side effects, age-related macular degeneration (AMD) or cancer associated retinopathy (CAR)?

Differential diagnosis of maculopathies can be difficult but is important if patients also suffer from other diseases such as breast cancer treated with antiestrogens. The main possible diagnoses, especially in the elderly, are age-related macular degeneration, tamoxifen and cancer-associated retinopathy (CAR).

We describe an 84-year-old patient with breast and colon cancer, who complained of a decrease in visual acuity after treatment with low-dose antiestrogens. She underwent a general ophthalmological investigation, perimetry and electroretinographic examination with multifocal (m-ERG) and flash-electroretinogram (flash-ERG).

Visual acuity was reduced to 1/50 and 0.3. The ophthalmological examination was normal, except for extensive bilateral maculopathy with shining crystalline deposits, central and peripheral visual field defects, slightly affected scotopic and photopic potentials in the flash-ERG, and an abnormal m-ERG.

The findings are expected with age-related macular degeneration with crystalline drusen, but also with CAR. Even if the single and total dosage of antiestrogens given to the patient is sufficient to cause tamoxifen retinopathy, this diagnosis can be excluded because, in tamoxifen retinopathy unlike in the case presented here, the deposits are not distributed in all retinal layers.