N-T asymmetry in tracking eye movements

1 April 2018 | Fiona Rowe (Prof) | EYE - Paediatrics, EYE - Strabismus

The current study aimed to quantify and compare the visual tracking responses of two sensory induced strabismic juvenile monkeys during monocular smooth pursuit, ocular following response and optokinetic nystagmus (OKN). Monkey 1 had esotropia and monkey 2 had exotropia. Both had dissociated vertical deviation (DVD) and fusion maldevelopment nystagmus. The main finding was that naso-temporal (N-T) asymmetry could be identified during all visual tracking eye movements with no significant difference in degree of asymmetry across the three tasks. There was no difference in onset latencies for nasal or temporal responses suggesting that directional asymmetry is not influenced by afferent processing delays. There was no difference in N-T gain ratios suggesting deficits arise in parts of the neural pathway common to all three tracking eye movements.