Multiple sclerosis (MS) is a chronic inflammatory disease that affects the central nervous system. It damages the myelin sheath that protects nerve fibers in the brain, optic nerves and spinal cord. This damage slows down or blocks messages between the brain and body, leading to symptoms such as numbness, weakness, fatigue, vision problems and impaired coordination. There is no single test that can diagnose MS. Doctors use a combination of tests and exams to help rule out other possible diseases and narrow in on a MS diagnosis. One test that is often used during the diagnostic process is an eye exam. Let’s take a closer look at how an eye exam can provide clues about MS.
What happens during an eye exam?
A standard eye exam involves several tests designed to evaluate visual acuity and eye health. Some of the common components include:
- Visual acuity test: This involves reading letters on an eye chart to test sharpness of vision.
- Retinal exam: The doctor will dilate the pupils with eye drops and then examine the back of the eye using an ophthalmoscope.
- Eye muscle movement evaluation: The doctor will ask you to follow a visual target such as a penlight as it moves in different directions to observe eye muscle coordination.
- Color vision test: This checks the ability to distinguish between certain colors.
Additional tests that may be performed during an eye exam for MS evaluation include:
- Visual field testing: This checks each eye’s full field of vision to identify any blind spots or areas of diminished vision.
- Optical coherence tomography (OCT): This imaging test looks at the thickness of the retinal nerve fiber layer.
- Visual evoked potentials: Electrodes measure how quickly visual signals are transmitted from the retina to the brain.
How can an eye exam detect signs of MS?
An eye examination can sometimes reveal changes that are characteristic of MS. Some of the potential indicators include:
Optic neuritis
Optic neuritis is inflammation of the optic nerve that can cause pain and vision loss in one eye. It occurs in about 1 in 4 people with MS, often early in the disease. Optic neuritis can be diagnosed during an eye exam.
Abnormal retinal exam
A dilated eye exam may show pallor or reduced blood flow in the optic nerve. Retinal nerve fiber layer thinning or swelling could also be visible. These signs can indicate optic nerve damage due to MS.
Vision problems
People with MS often experience visual disturbances including blurred or double vision, contrast sensitivity loss, and problems with depth perception or color desaturation. Testing visual acuity and visual fields can help detect these issues.
Nystagmus
This causes involuntary eye movements or shaking. It suggests a problem with the optic nerve, brainstem or cerebellum – all areas impacted by MS.
Reduced visual evoked potential speed
The slowed transmission of visual signals from eye to brain measured on visual evoked potential testing can indicate demyelination of optic nerve fibers caused by MS.
What other findings suggest MS?
While eye examination findings can provide important clues, other test results are also needed to diagnose MS. Additional symptoms and MRI imaging tests that may point towards MS include:
Neurologic symptoms
MS causes an array of neurologic symptoms that tend to wax and wane over time. These include:
- Numbness or weakness in one or more limbs
- Electric shock sensations with neck movement
- Tremor
- Unsteady gait
- Dizziness or vertigo
- Fatigue
- Bladder dysfunction
- Cognitive changes
Brain and spinal cord lesions
MRI scans of the brain and spinal cord in people with MS often show areas of demyelination (lesions or plaques) in white matter. Specific patterns of lesion location can help support an MS diagnosis.
Conclusion
While an eye exam alone can’t definitively diagnose MS, it plays an important role by checking for optic nerve damage and vision problems commonly caused by MS. When eye exam findings are combined clinical symptoms and MRI imaging, the information can help doctors determine whether MS is the underlying cause. Catching MS early is beneficial for starting treatment quickly to limit future disability. So don’t neglect regular eye exams, as they can sometimes provide the first hint that MS may be developing.