Vestibular Adaptations Of Vestibulo Ocular Reflex
Published on: 2018/07/21
Dr. Harshita Yadav
Vestibular-Ocular Reflex (VOR)
It is the reflex activity produced by the movement of the eyes in the opposite direction in order of response to the movement of the head in a particular direction.
The movement of the head is detected by the motion sensors through central neuronal pathways which lead to conjugate eye movement in the same degree and velocity so that the external world image remains stable on the fovea.
Healthcare, Vestibulo ocular reflex, Ophthalmology
Vestibulo ocular reflex (VOR) is the reflex that causes eye movement with respect to the activation of the vestibular system. The main function of this reflex is to stabilize the image on the retina during the head movement. For instance, if the head moves to the left side, the eye moves to the right. Patients with vestibulo ocular dysfunction may find it difficult to read.
Symptoms of vestibulo ocular reflex dysfunction
One of the common complaints of people with VOR is that they have problems with focusing on an object or the object is moving or revolving around them. Some common symptoms are,
- Oscillopsia – Jiggling or bouncing visual field
- Diplopia – double vision
However, the problem seems to disappear when the head is still.
Vestibulo ocular reflex nystagmus & other impacts due to VOR dysfunction
- Patients with impaired VOR may have nystagmus. Nystagmus is an excessive to and fro movement of the eyes.
- Apart from the above-mentioned symptoms, they may have photosensitivity, difficulty with moving objects, fluorescent lights or flickering lights. They may also have difficulty with high contrast patterns.
- Difficulty in reading text on the computer. This is because of the sensitivity to the flickering screen and scrolling pages.
- They may have difficulty with peripheral vision. The information from the peripheral vision is vital for orientation and sense of balance. Patients with impaired VOR may have visual flickers which they may perceive as a bird flying past.
Diagnosis of VOR
Eye examination tests and electronystagmography (ENG) can help to evaluate impaired VOR. In ENG, the eye movements are recorded in these tests using small electrodes place around the eyes. It can also be performed using videonystagmography (VNG) where a video camera mounted on a pair of goggles is used. These tests are carried out by trained specialists and they consider various factors such as medications and health conditions, sleep disorders, migraine or depression.
Read more – Vestibular adaptations of Vestibulo-ocular reflex by Dr. Harshita Yadav. In this article, Dr. Harshita discusses the various conditions of VOR with the help of illustrations.
Treatment for VOR
The treatment may involve surgery, optometric therapies, and medication. Patients with chronic vestibular reflex disorder need exercises which may help to reduce the impact of VOR impairment on the vision. The exercises mainly involve coordinating head-eye movements, stimulating the symptoms of dizziness and improving body balance by improving fitness.