Ocular Motor Abnormalities and Reading Difficulties in Different Neuro-Ophthalmic Diseases (S16.002)

Objective: Use a rapid reading test to assess reading difficulties and to perform eye movement recordings in different neuro-ophthalmic diseases.

Background: Neurological issues like stroke, cancer, neurodegeneration, and others frequently lead to vision loss, eye movement abnormality, or both, resulting in difficulties with common daily visual functions including saccadic reading.

Design/Methods: We recruited and assessed reading and visual disability at a single institution in over 200 controls and patients with different neuro-ophthalmic diseases, including homonymous hemianopia, eye movement disorder, and Parkinson’s disease. Subjects read 120 single digit numbers as fast as they could, which helped assess basic ocular motor and cognitive abilities necessarily during left-to-right saccadic reading without semantic context. Seventy controls and patients underwent 500-Hz binocular 2D infrared oculography (SensoMotoric Instruments) in order to quantify their saccade and fixation parameters during reading.

Results: Patients with cerebellar ataxia (n=8; p=0.001) read the slowest, about 35% slower compared with controls (n=122), followed by those with down-beating nystagmus (n=23; p=0.004), Parkinson’s disease (n=54; p= 0.001), and homonymous hemianopia (n=16; p=0.06). Infrared oculography revealed that patients with hemianopia exhibited striking spatial bias toward their visual field defect, during visual tasks and left-to-right reading. In contrast, patients with eye movement abnormality exhibited no spatial bias but had significantly greater total scanpaths while reading 120 numbers (p<0.005). Those with cerebellar ataxia and down-beating nystagmus had 27% smaller saccade amplitudes (p<0.005) and 17% greater fixation dispersion (p<0.01). Patients with Parkinson’s disease also exhibited no left-right spatial bias and greater total scanpaths (p=0.001). They had increased number of fixations (p=0.004) and saccades (p<0.001) but normal saccade amplitudes and fixation dispersion during reading.

Conclusions: Single digit number reading test is an easy way to assess reading difficulties in the clinical setting, and eye movement recording reveals a variety of ways that reading can be impacted in different neurological conditions.

Disclosure: Dr. Oh has nothing to disclose. Dr. Shariati has nothing to disclose. Dr. Jehangir has nothing to disclose. Dr. Yu has nothing to disclose. Dr. Chen has nothing to disclose. Dr. Yu has nothing to disclose. Dr. Liao has nothing to disclose.