TouchDx® introduces the OKN+ for the iPhone, a diagnostic application used in the neurosciences to evaluate eye movements. Our application allows for the replacement of the Optokinetic Nystagmus (OKN) Test drum and ribbon .Optokinetic nystagmus (both horizontal and vertical) is a normal physiological response. OKN testing is very useful in detecting subtle abnormalities or asymmetries in saccadic or smooth pursuit eye movements. The test may also be used in the evaluation of physiological and non-physiological blindness.
Classically OKN is elicited by moving a thick ribbon containing parallel red and white stripes either horizontally or vertically in front of the eyes. Two alternating eye movement patterns are observed. The first involves a slow phase towards the direction of stripe movement (mediated by the ipsilateral posterior cortex and connections to the vestibular nuclei and the cerebellum (flocculonodular lobe) projections to the paramedian pontine reticular formation (PPRF) and abducens nuclei). Second, the fast phase is observed with the eyes moving back to midline (mediated by the frontal eye fields projecting to the contralateral PPRF). Alterations in either the slow or fast phases may be localized to the pathways described above.
As part of the OKN+ suite TouchDx® includes the Red Desaturation (RD) Test, a diagnostic application used in ophthalmology and the neurosciences to assess for optic nerve or chiasmal pathology.
The phenomenon of red desaturation is recognized as an early indicator of neurological field deficits and optic nerve injury. Red desaturation may occur disproportionately to retention of visual acuity and form perception.
Instructions for use:
Test optokinetic nystagmus (OKN) by holding the iPhone screen with parallel stripes in front of the patient's eyes and asking them to watch the stripes go by. Normally, rhythmic eye movements called nystagmus occur consisting of an alternating slow phase with slow pursuit movements in the direction of strip movement, and a rapid phase with quick refixations back to midline.
Red Desaturation Test for optic nerve or chiasmal injury. In a well-lit examination room, the examiner covers one of the patient’s eyes with an occluder. The patient is then shown the iPhone screen and asked if it appears red in color. The contralateral eye is then occluded and process repeated allowing for the patient to determine if a difference exists in the richness of the red color between the left and right eye. The affected eye is identified by the one in which the red color is less bright and less rich in color.
- OKN+ can determine optokinetic nystagmus, an extremely sensitive, and reproducible test of brain function. When used properly it can provide information on the integrative state of each cerebellum individually, each parietal lobe individually, and each frontal lobe individually.
- OKN+ is always at your fingertips and does not need to be washed or sanitized!
- OKN+ is a convenient and an easily portable diagnostic tool that can be used to help assess a variety of visual deficits and optic nerve injury.
- OKN+ has clinical utility in a variety of medical disciplines including Neurology, Neuro-Opthamology, Opthamology and Optometry?