Bitemporal hemianopia (BH) is a well recognized visual field defect with a broad differential diagnosis, including chiasmal lesions such as pituitary macroadenoma, craniopharyngioma, Rathke’s cleft cyst, meningioma and chiasmal glioma. Less common causes of BH include demyelination, inflammatory causes such as sarcoidosis, lupus and lymphocytic hypophysitis, ethambutol toxicity and aneurysm. Bitemporal pseudo-hemianopia secondary to TDS is rare but should be included in the differential list. TDS is a congenital anomaly which can cause bitemporal visual field defect due to nasal ectasia of the ocular globe.  Magnetic Resonance Imaging (MRI) findings include focal thinning and ectasia of the nasal sectors of the posterior walls of the globes and flattening of the temporal portion.  TDS is generally a benign condition with good prognosis, but worsening of the visual field defect, progression of refractive error, color vision impairment, subretinal fluid leakage and retinal detachment have been reported.

TDS can cause bitemporal visual field defect mimicking chiasmal lesions.  Although it is a benign condition that does not require any interventions, ocular complications resulting in visual loss can rarely occur.  Hence recognition of this condition and regular follow up with ophthalmologist is important.