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Vestibular disorders frequently disrupt vision because the vestibular and visual systems must work in harmony to stabilize our gaze. When the vestibulo‑ocular reflex (VOR) is impaired, everyday head movements can cause objects to appear blurry, bouncy, or even spinning—a phenomenon known as oscillopsia—or lead to double vision; these issues often ease when the head is held still. Traditional eye exams, performed with the head at rest, may miss these symptoms since the eyes themselves may be healthy; rather, the challenge lies in how the visual system interacts with balance centers. To properly address these vision problems, a neuro‑optometric rehabilitation assessment, focusing on ocular motor control, focusing, tracking, and binocular coordination is often recommended, especially when visual issues may provoke or worsen vestibular symptoms.
Vestibular disorders often cause difficulty with vision because the vestibular and visual systems work together to stabilize vision.
The ‘eye ear’ connection is known as the vestibulo-ocular reflex (VOR). The VOR plays a critical role in maintaining eye stability during head motion. This is known as gaze stability. The VOR also sends signals to the postural muscles of the trunk, arms, and legs, which help us maintain our balance.
A disrupted or impaired VOR can result in abnormal vestibular nystagmus, a reflexive motion in which the eyes appear to jerk in one direction and then slowly reset in the opposite direction.
The visual and vestibular systems send signals back and forth to inform our brains about our movement in space. When a person has a vestibular disorder, the inner ear sends abnormal signals to the muscles that control eye movement. This can cause a slight misalignment of the eyes. It is essential to address these misalignments to achieve optimal symptom reduction.
The inner ear includes a unique type of sensory hair cell that responds to head motion. When the head rotates, the hair cells move, and this triggers the firing rate in the vestibular nerve, which sends this signal to the brain, eyes, and postural muscles.
In the absence of motion, both inner ears are sending a signal to the brain. The amount of signal from the left and right ears should be similar. Typically, this signal becomes asymmetric when the head rotates to one side. For example, when the head turns toward the right, the firing rate from the right vestibular nerve increases while the firing rate from the left vestibular nerve decreases. The brain interprets the difference in firing rate as a rotation (or motion) of the head. This information is used to provide stability to the eyes and postural muscles during head motion, helping us maintain balance. Therefore, if the vestibular system is not working correctly in one ear (or both), then the brain does not receive correct information about head motion from the vestibular nerves, which results in symptoms such as vertigo, imbalance, or oscillopsia (jumping vision).
It is common for patients with vestibular disorders to experience significant visual complaints, such as focusing on an object or perceiving that objects are moving from side to side or revolving around them (vertigo). Their visual field may jiggle or bounce during head motion (oscillopsia), or they may have double vision (diplopia). The eyes often feel tired and strained.
Many patients with a vestibular disorder may also experience photosensitivity (discomfort in bright light) and other vision problems, such as intense discomfort with flickering lights, particularly from fluorescent lights or highly reflective surfaces. Environments with a combination of fluorescent lighting and busy patterns or moving objects are especially problematic, which is why shopping in large stores may be very difficult. Special tints can be prescribed to reduce these symptoms.
Reading text on a printed page can be difficult for people with an impaired VOR, because the small head motion destabilizes gaze. The result is words and letters that appear to oscillate and shift. Reading text on a computer monitor may be problematic due to heightened sensitivity to screen flickering or scrolling pages of text. Scrolling text is challenging due to the motion of the words and the increase in the number of eye movements that are needed to be performed.
Patients with vestibular disorders are acutely aware of any visual distortion. Therefore, consideration needs to be given to determine the appropriate type of lens correction to use. Frame selection and base curve of the lens are essential to minimize any distortion.
Individuals with vestibular disorders often experience a visual dependence, where the brain becomes reliant on vision to maintain balance due to unreliable signals from the inner ear. This may lead to symptoms when a person’s visual field is overwhelmed, for example, by busy patterns on wallpaper, or when they lack a point of fixation, such as in darkness or wide-open spaces. Typical comments from such patients include:
During a routine eye exam, in-depth testing of the binocular system is not typically done. Therefore, eye misalignments are often not detected. This is especially true when the misalignment only manifests with specific head movements. Consequently, it is recommended that patients consult with an optometrist who specializes in Neuro Optometric examinations and treatment.
The Neuro Visual Optometric evaluation assesses the visual, ocular motor, and focusing skills necessary for stabilizing the sensory-motor components of the vestibulo-ocular reflex (VOR).
The eyes are a window into the inner ear. Some laboratory tests used to diagnose a vestibular disorder involve evaluation of the vestibular system based on eye movements. For example, electronystagmography (ENG) is a battery of tests to measure brain and vestibular-originated eye movements. Included in the test battery is the measurement of nystagmus that may occur when the head is placed in certain positions or when one ear is stimulated with warm (or separately cold) water or air, known as the caloric test. The eye movements are recorded using small electrodes placed on the skin around the eyes or with a video camera mounted to a goggle frame (known as video-nystagmography or VNG). Rotation testing employs the same electrodes or goggles to measure the relationship between the velocity of the head and eyes during whole-body rotation.
The first approach to resolving most vision problems associated with visual-vestibular disorders is to eliminate ocular or functional visual issues, such as eye fixation and eye movement, focusing, and binocular teaming problems. An evaluation by an optometrist (OD) specifically trained to address the vestibular patient is necessary to diagnose and treat these problems.
Neuro-optometric treatments are an essential component of treatment, especially if an underlying focusing, ocular malalignment, visual acuity, or visual processing problem is suspected in addition to the vestibular disorder. Such optometric therapies may involve the use of corrective lenses, including prisms and spectacles, tints, and treatments to enhance vision and functional visual skills, such as fixation, eye movement, focusing, and eye teaming ability. It is crucial to address any visual problems, no matter how small, for vestibular rehabilitation therapy to be maximally effective.
Vestibular physical therapy incorporates exercises designed to improve gaze and gait stability, reduce head motion-induced dizziness, decrease fall risk, and enhance overall fitness.
Vestibular disorders can be disabling and thus tempt those affected to stay home and avoid head motion or visual stimulation. However, this will undermine the brain’s ability to adjust and recover. Treatment is most effective when visual and vestibular therapies are combined.
Authors: Michael C. Schubert, PT, PhD, Kenneth Ciuffreda, O.D., PhD, FCOVD-A, Allen H. Cohen, O.D., FCOVD, and Cheryl Berger Israeloff, OD
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