Double Vision Could Signal Stroke, Warns Leading Eye Surgeon
Experiencing double vision is frequently dismissed as a consequence of fatigue or stress, but it could be a critical warning sign of a stroke, according to a prominent eye surgeon. Medically termed diplopia, double vision involves perceiving two images when viewing a single object, as defined by the NHS, and it can impact either one or both eyes.
Urgent Medical Assessment Required
Dr Nadeem Ali, Consultant Squint and Double Vision Surgeon at the London Squint Clinic, emphasises that double vision is commonly associated with brain tumours but can also signal a stroke. He states, 'When someone develops double vision out of the blue, particularly if they have never experienced it before, that always warrants urgent assessment.'
If double vision occurs alongside facial drooping, limb weakness, slurred speech, difficulty walking, or severe dizziness, it must be treated as a medical emergency. A sudden, severe headache accompanying double vision is another significant red flag.
'Painful double vision, especially with a new or intense headache, can indicate acute inflammation, infection, or a bleed,' Dr Ali explains. 'That is not something to wait out at home.'
Understanding Stroke Types and Vision Impact
There are two primary types of stroke. Ischemic strokes, which constitute 80 percent of cases, occur when a blockage in a blood vessel impedes blood flow to part of the brain. The second type, hemorrhagic strokes, are rarer and happen when a blood vessel bursts, flooding brain areas with excessive blood while depriving others of adequate supply.
Dr Ali notes that double vision can also signal a transient ischaemic attack (TIA), often called a 'mini-stroke'. A TIA involves a temporary disruption of blood flow to the brain, causing sudden, stroke-like symptoms that typically last minutes to an hour but resolve within 24 hours. TIAs frequently precede a stroke, making observation and medical attention crucial.
Vision Problems as Stroke Complications
According to the RNIB, vision problems are common complications of stroke because it can affect nerves and brain regions involved in the visual pathway, responsible for processing and interpreting visual information. The charity identifies main eye issues post-stroke, including:
- Visual field loss
- Eye movement problems
- Visual processing problems
Individuals may also struggle with judging depth and movement, recognising objects and people, and experience visual hallucinations.
Other Potential Causes and Importance of Early Intervention
While double vision does not always indicate a stroke, Dr Ali urges people to take the condition seriously. 'The nerves that control eye movement originate in the brain. If one stops working properly, we must establish why.'
If symptoms develop gradually without other issues, double vision might stem from loss of eye control. Diplopia occurs when eyes are misaligned, potentially due to problems with eye muscles, controlling nerves, or the brain. 'In adults and children, particularly when it appears suddenly, we never just put it down to simple eye strain,' he adds.
People often attribute it to screen strain or tiredness, but true double vision is abnormal and should not be ignored. In cases of glioblastoma, a rare and aggressive brain cancer, double vision is a common symptom, typically caused by increased brain pressure from swelling or tumour pressure on eye movement nerves.
Other causes include diabetes, multiple sclerosis, thyroid issues, or eye strain from excessive close-up work. Regardless of the cause, early intervention allows doctors to rule out serious conditions promptly and begin appropriate treatment, such as prism lenses, medication, or surgery.
Dr Ali concludes, 'The key message is simple: if you suddenly start seeing double, particularly with other symptoms, seek medical advice immediately. It is always safer to be checked than to miss something serious.'
