More clinical observations on migraine associated with monocular visual symptoms in an Indian population.

CONTEXT: Retinal migraine (RM) is considered as one of the rare causes of transient monocular visual loss (TMVL) and has not been studied in Indian population.

OBJECTIVES: The study aims to analyze the clinical and investigational profile of patients with RM.

MATERIALS AND METHODS: This is an observational prospective analysis of 12 cases of TMVL fulfilling the International Classification of Headache Disorders-2nd edition (ICHD-II) criteria of RM examined in Neurology and Ophthalmology Outpatient Department (OPD) of Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh from July 2011 to October 2012.

RESULTS: Most patients presented in 3(rd) and 4(th) decade with equal sex distribution. Seventy-five percent had antecedent migraine without aura (MoA) and 25% had migraine with Aura (MA). Headache was ipsilateral to visual symptoms in 67% and bilateral in 33%. TMVL preceded headache onset in 58% and occurred during headache episode in 42%. Visual symptoms were predominantly negative except in one patient who had positive followed by negative symptoms. Duration of visual symptoms was variable ranging from 30 s to 45 min. None of the patient had permanent monocular vision loss. Three patients had episodes of TMVL without headache in addition to the symptom constellation defining RM. Most of the tests done to rule out alternative causes were normal. Magnetic resonance imaging (MRI) brain showed nonspecific white matter changes in one patient. Visual-evoked potential (VEP) showed prolonged P100 latencies in two cases. Patent foramen ovale was detected in one patient.

CONCLUSIONS: RM is a definite subtype of migraine and should remain in the ICHD classification. It should be kept as one of the differential diagnosis of transient monocular vision loss. We propose existence of "acephalgic RM" which may respond to migraine prophylaxis.