Macular oedema due to letrozole: a first case report

A 72-year-old woman presented with unexplained, progressive, painless visual loss in the right eye during the past six months. At presentation visual acuity (VA) was 3/60 in the right eye and 6/6 in the left eye. Anterior segment examination and intraocular pressures were normal. Dilated fundoscopy revealed significant macular oedema in the right eye and a normal fundus appearance in the left eye. Her medical history was noteworthy for breast ductal carcinoma in situ, for which she had undergone right mastectomy three years earlier. She had not received chemotherapy or radiotherapy but she had been under treatment with letrozole 2.5 mg/day over the past three years. She did not receive any other medication. Optical coherence tomography showed intraretinal fluid and a significant increase in retinal thickness in the foveal and parafoveal areas, while fluorescein angiography detected foveal hyperfluorescence and leakage of the dye in the late phase. Multifocal electroretinogram showed a decreased response in both eyes. In suspicion of letrozole-related retinopathy, the patient was advised to stop the medication. The patient agreed to receive an intravitreal injection of 0.05 ml/0.5 mg ranibizumab. One month later, VA in the right eye was 6/9 and macular oedema had apparently improved. This is the first reported case of letrozole-associated macular oedema treated with intravitreal ranibizumab.