Reading difficulty after stroke: ocular and non ocular causes.

Background: Ocular causes of reading impairment following stroke include visual field loss, eye movement impairment and poor central vision. Non ocular causes may include cognitive errors or language impairment.

Aim: The purpose of this study was to identify all patients referred with suspected visual impairment who had reported reading difficulty to establish the prevalence of ocular and non ocular causes.

Methods: Prospective, multicentre, observation study with standardised referral and assessment forms across 21 sites. Visual assessment included visual acuity measurement, visual field assessment, ocular alignment, and movement and visual inattention assessment. Multicentre ethical approval and informed patient consent were obtained.

Results: A total of 915 patients were recruited, with a mean age of 69·18 years (standard deviation 14·19). Reading difficulties were reported by 177 patients (19·3%), with reading difficulty as the only symptom in 39 patients. Fifteen patients had normal visual assessment but with a diagnosis of expressive or receptive aphasia. Eight patients had alexia. One hundred and nine patients had visual field loss, 85 with eye movement abnormality, 27 with low vision and 39 patients with visual perceptual impairment. Eighty-seven patients had multiple ocular diagnoses with combined visual field, eye movement, low vision or inattention problems. All patients with visual impairment were given targeted treatment and/or advice including prisms, occlusion, refraction, low vision aids and scanning exercises.

Conclusions: Patients complaining of reading difficulty were mostly found to have visual impairment relating to low vision, eye movement or visual field loss. A small number were found to have non ocular causes of reading difficulty. Treatment or advice was possible for all patients with visual impairment.