Temporary Blindness

23/04/2025

Temporary blindness, also referred to as transient visual loss (TVL), can be an alarming symptom to the patient and may be challenging to the treating ophthalmologist.

TVL may be a manifestation of an underlying ophthalmic or systemic disease. Causes are diverse and may include life-threatening conditions like diseases affecting the neck vessels or the heart or relatively benign conditions like migraines. Proper evaluation of patients presenting with this symptom is mandatory to find the underlying cause and manage it appropriately. 

Etiology

TVL is more common in adults than in children, may affect one eye (monocular) or both eyes (binocular) and it may last from seconds to hours. When TVL is monocular, the lesion may be at the level of the eye or optic nerve, causes may include a dislodged blood clot originating form the internal carotic artery in the neck  or the heart local thrombosis of the blood vessels of the retina or optic nerve, vascular spasms or retinal migraines among others.

Binocular TVL usually originates from brain lesions and may be caused by certain types of epilepsy, complex migraines, increased brain fluid pressure and optic nerve swelling, Decreased blood flow to the optic nerve, retina or brain, etc.

Other causes of TVL include glaucoma, orbital tumors and inflammation (giant cell arteritis)

Presentation and exam

Symptoms may be variable depending on the underlying cause of the disease. A proper history regarding timing, pattern, provoking factors, and associated symptoms can often provide a clue to the cause of the episode.

In case of emboli, loss of vision is sudden and painless; the patient may describe a dark curtain falling or raising in one eye. In some cases, visual loss may be described as cloudiness of vision in one eye.

In cases of giant cell arteritis (which an inflammation of the temporal artery), visual loss is usually of short duration (2 to 4 minutes), may change depending on posture, may recur many times, and may be associated with flashes of light. There may be associated features like headaches, jaw claudication, scalp tenderness, fever, etc

Patients with heart failure or low blood pressure may present with temporary blindness which is typically bilateral and frequently accompanied by lightheadedness and confusion.

Retinal migraine patients may complain of flashing lights, shining visual defect or partial visual loss associated with headaches. Visual loss in those cases is transient, lasting 5 to 20 minutes, and may recur several times during the day.

Management and treatment

Even if vision loss was transient and resolved, it is advisable to visit your doctor as soon as possible. It is very important to distinguish whether the episode of TVL is due to a high-risk cause or a low-risk cause. Your physician will take a detailed history of the episode and about your general condition. He will later perform a full ophthalmological exam. As patients with TVL caused by a vascular underlying disease may be at a higher risk of stroke, they require cardiac and systemic evaluation which may include assessment of hypertension, diabetes mellitus, and dyslipidemia as well as imaging studies such as carotid doppler ultrasound, angiography, and cardiac echocardiography to localize the source of the blood clot Other studies may be required depending on the suspected etiology.

Treatment will be directed towards the underlying cause. In cases where the diagnosis is uncertain, adequate follow-up care is important. Children with unexplained transient visual disturbances should be closely monitored.