Head-Cancelled Virtual Reality for Ocular Cranial Nerve Palsies

OCNP Group Inclusion Criteria: * Presence of OCNP in one eye with 50% range-of-motion limitation or worse * Able to provide informed consent and will be able to fluently read and understand spoken English OCNP Group Exclusion Criteria: * Presence of bilateral OCNP * Range of motion better than 50% * Visual acuity worse than 20/100 in either eye * Greater than 4-line difference in visual acuity between the eyes, * Structural anomalies or sensory sensitivities (e.g. visual motion sensitivity) that would prevent them from wearing or tolerating a VR headset Participants will be excluded if they are unable to participate if inclusion criteria are not met. Normal Group Inclusion Criteria: * Absence of OCNP or other neurological or neuro-ophthalmic diseases * No strabismus * Have normal or near-normal vision with glasses or contact lenses. * Be able to provide informed consent and will be able to fluently read and understand spoken English Normal Group Exclusion Criteria: * Visual acuity worse than 20/100 in either eye * Greater than 4-line difference in visual acuity between the eyes * Structural anomalies or sensory sensitivities (e.g. visual motion sensitivity) that would prevent them from wearing or tolerating a VR headset * Known inability to tolerate visual testing of at least 20 minutes continuously.