Changes in vision, including blurred sight, flashing lights, or double vision, may be among the earliest indicators of multiple sclerosis (MS), an incurable autoimmune disease that affects the central nervous system. A 2025 study indicated that visits to neurology and ophthalmology specialists can increase eight to nine years before an MS diagnosis.
Multiple sclerosis damages myelin, the protective sheath around nerves, particularly in the brain and spinal cord. This damage can also affect the optic nerves, which are heavily coated in myelin and thus particularly vulnerable. Damage to the optic nerves causes optic neuritis, a condition that can lead to symptoms such as eye pain, blurred vision, blind spots, washed-out colors, and flashing lights. While optic neuritis often resolves on its own within a few weeks, it can be the first sign of MS.
Sasha Clark, 28, experienced significant vision changes in January 2018. Initially dismissing it as a migraine, she found that closing one eye improved her limited vision. Within two weeks, her condition worsened, impacting her coordination, balance, and causing extreme fatigue. After two months, she was diagnosed with MS.
"MS doesn’t always start with obvious mobility problems. For some people, vision changes or problems with fine motor skills can be among the first signs," Clark said. She advises others to trust their instincts and seek medical attention if they feel something is not right.
Besides optic neuritis, MS can also disrupt nerve pathways controlling eye movements, leading to double vision, difficulty reading, or distorted straight lines. These visual disturbances are often accompanied by other MS symptoms like unsteadiness or nausea, as the brain areas controlling eye movement are near those affecting balance and coordination.
Another less common visual symptom is oscillopsia, where surroundings appear to bounce while walking due to the brain's inability to stabilize visual information. These visual symptoms typically evolve over days, persist for a period, and then begin to improve, especially with prompt MS treatment.
Researchers are working to identify individuals at higher risk of developing MS by studying the period before a diagnosis or clinical onset of typical symptoms. This research aims to combine insights from vision changes with other data to potentially identify at-risk individuals earlier.