Ophthalmic and Oculomotor Characteristics in Ataxia-Telangiectasia: A Clinical Cohort Study using Video-Oculography

To characterise the ophthalmic and oculomotor features of Ataxia-Telangiectasia (A-T) and to evaluate the feasibility and utility of video oculography as part of a comprehensive visual assessment.

Thirty participants aged 3 to 36 years (15.7 $\pm$ 9.8 years) with genetically confirmed A-T underwent detailed ophthalmic evaluation, including visual acuity, refraction, binocular function, slit-lamp and fundus examination, including optical coherence tomography. Non-invasive eye movement recordings of self-paced and reflexive saccades, smooth pursuit and gaze-holding in horizontal and vertical planes were made using the EyeSeeCam video-oculography (VOG) system.

Visual acuity was preserved in most patients, with 24 (79%) achieving 6/12 or better. Refractive errors were present in 15 (50%), predominantly low hyperopia or myopia. Strabismus was identified in four (13%) and moderate to severe conjunctival telangiectasia was present in 20 (67%) patients. Eye movement recordings revealed hypometric saccades, increased latency, impaired smooth pursuit (especially vertical) and frequent nystagmus. Self-paced saccades emerged as the most reliable and interpretable oculomotor measure, with counts over a 30-s period ranging from 8 to 58 (median = 20), reflecting significant variability in volitional eye movement control.

Patients with A-T exhibit a spectrum of ophthalmic abnormalities, with significant oculomotor dysfunction despite relatively preserved acuity. Self-paced saccade metrics derived from VOG recordings offer a robust and interpretable measure of oculomotor function, and may serve as adjunctive biomarkers for disease monitoring and treatment evaluation. The integration of VOG into clinical assessment provides qualitative and quantitative insights into eye movement control in A-T.