Walsh & Hoyt: Dyslexia Related to Abnormal Vision, Attention, or Eye Movements

Some patients with visual field defects have reading problems despite normal or near-normal visual acuity. Patients with complete homonymous hemianopia may complain of reading problems, hence the term hemianopic dyslexia. This mainly occurs when the central 5 degrees are affected. Overall reading speed is more prolonged for patients with right hemianopia than for those with left hemianopia. With languages written from left to right, patients with left hemianopia have trouble finding the beginning of lines, since the left margin disappears into the field defect as they scan rightwards. Marking their place with an L-shaped ruler can reduce this frustration. Right hemianopia prolongs reading times, with increased fixations and reduced amplitude of reading saccades to the right. Smaller type and learning to read obliquely with the page turned nearly 90 degrees may help. Reading performance can improve with time as both types of patients learn adaptive strategies. Complete bitemporal hemianopia. Simultanagnosia. Peripheral dyslexia. Left hemineglect.