The most common multiple sclerosis eye symptoms are blurry vision or decreased vision in one eye. This is caused by a condition called optic neuritis

Story by: David Steen Martin; Reviewed by Jocelyn H. McGuire, APRN on September 27, 2023

Blurred vision, eye pain, double vision and other eye conditions are common with multiple sclerosis (MS) and are often the first sign of the disease. The most common MS eye symptoms are blurry vision or decreased vision in one eye. This is caused by a condition called optic neuritis, which also can cause a graying of vision or a blurred or blind spot in the center of the field of vision, leaving an MS patient to rely on their peripheral vision.

Pain with eye movement typically occurs before or during vision loss or other symptoms, which tend to worsen for several days before improving.

“As an MS symptom, visual impairment is usually temporary and can be worsened by stress, fatigue, infection, certain medications or an increase in temperature,” said Jocelyn H. McGuire, APRN, a nurse practitioner at the Norton Neuroscience Institute Hussung Family Multiple Sclerosis Center. “Managing these external factors may improve the associated visual symptoms.”

How MS causes vision impairment

MS is an autoimmune disease that causes the body to mistakenly attack myelin, an insulating coating around nerves in the central nervous system, including the optic nerve. The brain itself and spinal cord also have myelin coating nerves.

Visual information is transmitted along the optic nerve to the brain. When myelin is damaged, inflammation results, and nerve signals from the eyes can be altered or stopped completely, causing vision loss.

Optic neuritis is often the first symptom of MS, but the condition alone does not necessarily mean someone has or will develop MS. Other potential causes of optic neuritis include other neuroimmune disorders like neuromyelitis optica spectrum disorder or MOG antibody disease as well as cytomegalovirus, Lyme disease and herpes. Optic neuritis affects about 70% of people with MS at some point in their lives. Most with optic neuritis experience a full or partial recovery of vision in four to 12 weeks.

Double vision and involuntary eye movement

MS also can result in other eye symptoms, including double vision (diplopia) and shaking or involuntary eye movement (nystagmus).

Unlike optic neuritis, which affects the optic nerve, MS damage in the brain causes double vision and involuntary eye movement. Diplopia results from weakness in the muscles controlling the eyes, causing double vision as the eyes move out of sync. Nystagmus causes a lack of muscle control.

So-called floaters, specks or spots that appear to float in front of everything, are another symptom common in MS patients, but MS may not be the cause. These appear during the normal course of aging when tiny strands of the gel-like fluid in the eyes stick together and cast a shadow on the retina at the back of the eye.

If floaters appear suddenly or are accompanied by light flashes or vision loss, they may signal an emergency that requires immediate attention from an eye specialist.

With MS eye symptoms, simply waiting for the inflammation to go down can be enough, especially if the symptoms occur as part of a relapse of the disease. For more severe attacks, a doctor may prescribe steroid treatments. Disease-modifying therapies can be used to address multiple sclerosis as a whole, including visual issues. An eye patch or yellow lenses also can help people cope with visual changes.

Because MS symptoms vary so much between individuals, everyone will experience vision issues differently. Those with MS should have regular evaluations by an ophthalmologist.