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Optic nerve and double vision problems

We see with the brain as much as with the eyes. The optic nerve carries signals from each eye to the brain, the brain builds the picture, and a set of nerves and muscles keeps the two eyes moving together so that we see one clear image. When something goes wrong along this path, the eyes themselves may look healthy, yet vision blurs, fades or doubles. Finding the cause often needs an eye examination and other doctors working together. ReNew Vision does the eye side of this care, and the eye doctor tells you when other doctors or tests are needed.

What problems are seen?

• Double vision (diplopia), sudden or gradual.
• Optic neuritis: inflammation of the optic nerve, usually in young adults.
• Sudden vision loss from the optic nerve, such as a stroke of the optic nerve in older adults.
• Swollen optic nerves from raised pressure inside the head.
• Weakness of the nerves that move the eyes, often linked with diabetes or high blood pressure.
• Thyroid eye disease affecting the eye muscles.
• Drooping lids and double vision that vary through the day, which can be a sign of myasthenia.
• Loss of part of the field of vision from a problem in the brain, for example after a stroke.
• Unequal pupils that are new.

When is it an emergency?

Some of these problems are signs of serious illness and cannot wait for an OPD appointment. Get help at once, day or night, if you have:

• sudden double vision with weakness or numbness of the face, arm or leg, slurred speech, confusion or difficulty walking. These can be signs of a stroke. Call 108 for an ambulance and go to the nearest hospital emergency department straight away.
• sudden double vision with a drooping eyelid, a widened pupil or a severe headache. This can be a sign of a bulging blood vessel (aneurysm) in the brain. Go to the nearest hospital emergency department at once.
• sudden loss of vision in one or both eyes, even if it comes back.
• new headache, pain on chewing, a tender scalp and blurred vision in someone over about 50. This can be inflammation of the arteries, which can cause blindness in both eyes if not treated quickly.
• a severe headache with vomiting and blurred vision.

Emergency eye care at ReNew Vision is available 24 hours; see eye emergency. If stroke signs are present, or you are far from Vasco, go to the nearest hospital emergency department first.

What happens at the eye examination here?

1. Your history: when the problem started, whether it came on suddenly, whether it changes through the day, and your general health, including diabetes, blood pressure, thyroid problems and recent illness.
2. Vision and colour vision in each eye. Faded colours in one eye can be a sign of an optic nerve problem.
3. Pupils: how they react to light, which can show whether an optic nerve is working normally.
4. Eye movements and alignment: the eyes are tested in each direction, and covered one at a time, to measure any squint.
5. Eyelids: drooping, and whether it changes.
6. Eye pressure.
7. The optic nerve, examined at the back of the eye, often after dilating drops.

Some tests are not done at ReNew Vision: visual field testing, scans of the optic nerve (such as OCT) and brain scans (MRI or CT). If you need one of these, or blood tests, the eye doctor explains why and what the next step is, and the results are reviewed with you.

Double vision

The first question is whether the double vision is in one eye or comes from the two eyes together. Cover one eye, then the other. If the doubling disappears when either eye is covered, the eyes are not lining up, and the cause is often in the nerves, muscles or brain. If it stays in one eye with the other covered, the cause is usually in that eye itself, such as a cataract, dry eye or a problem with the cornea or spectacles. Both kinds need an eye check; the first kind, when sudden, needs it the same day. Read sudden double vision: causes and when it is an emergency.

Optic nerve problems

Optic neuritis

Optic neuritis is inflammation of the optic nerve. It usually affects one eye of a young adult: vision blurs or dims over a few days, colours look washed out, and the eye aches, especially on moving it. Many people recover much of their vision over the following weeks and months. Optic neuritis can be linked with conditions such as multiple sclerosis, so it is usually looked after together with a neurologist, and a brain scan is often advised.

Stroke of the optic nerve

In older adults, the blood supply to the optic nerve can fail suddenly, often noticed on waking as a loss of the upper or lower half of the vision in one eye. Diabetes, high blood pressure and sleep apnoea are linked with it. In people over about 50 with headache or scalp tenderness, inflammation of the arteries must be ruled out the same day.

Swollen optic nerves

Raised pressure inside the head can make both optic nerves swell. Signs include headaches, brief greying-out of vision, and sometimes double vision. The cause must be found, usually with a brain scan, and treatment is shared with a neurologist or physician.

Medicines and nutrition

Some medicines, including some medicines used for tuberculosis, can affect the optic nerve. If you are on TB treatment and notice blurred vision or faded colours, tell your doctor at once. A lack of some vitamins, sometimes with heavy drinking or tobacco use, can also damage both optic nerves slowly.

Glaucoma

Glaucoma is also a disease of the optic nerve, usually linked with eye pressure. It is covered on glaucoma check-up and treatment.

Working with other doctors

Many optic nerve and eye-movement problems are signs of something happening elsewhere in the body: in the brain, the blood vessels, the thyroid or the immune system. The eye examination often gives the first clue. When you need a neurologist, a physician, a thyroid doctor or a brain scan, the eye doctor writes a referral with the eye findings, tells you how urgent it is, and continues your eye care here. A long-standing squint that causes double vision may be helped by squint surgery, which is done at ReNew Vision; see squint surgery.

How do I book?

• Where: ReNew Vision Eye Hospital, 2nd floor, Pai Hospital building, Vaddem Merces Road, Vaddem, Vasco da Gama, Goa 403802. See timings and directions.
• When: Eye OPD Monday to Saturday, 4 pm to 7 pm. Sunday OPD closed. Emergency eye care: 24 hours.
• Call or WhatsApp: 072489 88039.
• Bring: your spectacles, a list of your medicines, recent sugar, BP and thyroid reports, any scan reports, and someone to take you home. Do not drive if you are seeing double.

Optic nerve and double vision guides

Questions patients ask

Is double vision an emergency?

New, sudden double vision should be seen the same day. If it comes with weakness, numbness, slurred speech, confusion, a drooping eyelid or a severe headache, call 108 and go to the nearest hospital emergency department at once.

Do I need a brain scan for double vision?

Not always. It depends on the cause the eye examination points to, your age and other symptoms. The eye doctor tells you whether a scan is needed, how urgently, and what the next step is.

What is optic neuritis?

Inflammation of the optic nerve, usually in one eye of a young adult. Vision blurs or dims over a few days, colours look washed out and the eye aches on moving. Many people recover much of their vision; a neurologist is usually involved too.

Can thyroid problems cause double vision?

Yes. Thyroid eye disease can swell and stiffen the muscles that move the eyes, causing double vision, staring or bulging eyes and irritation. It is looked after together with your thyroid doctor.

Is a visual field test done at ReNew Vision?

No. If you need a visual field test, the eye doctor will tell you and explain the next step, and can go through the results with you at ReNew Vision.

This page is general eye-health information, not personal medical advice. Your eye doctor advises you after examining your eyes.