What Causes Vision Loss from Uveitis?

Uveitis is a common cause of vision loss and blindness in the United States and in the world. Uveitis may cause blurry and reduced vision. When treated, vision may recover. In some cases, mostly in intermediate uveitis, posterior uveitis and panuveitis, where inflammation is recurrent and chronic, damage to the eye can occur, particularly to the retina and optic nerve, and cause permanent visual loss.

Cystoid Macular Edema (CME) ► Cystoid Macular Edema (CME) ▼

This is a complication seen in intermediate uveitis, posterior uveitis, and panuveitis.

The leading cause of decreased vision which may lead to permanent visual loss is the development of CME – swelling of the macula which is the most sensitive part of the eye for vision needed for driving, reading and detailed work. If the swelling does not respond to treatment and is long standing, the sensitive cells under the fluid can eventually die. Other causes are swelling of the optic nerve. With the nerve swollen, messages from the retina cannot effectively get to the brain.

Damage to the Vitreous ► Damage to the Vitreous ▼

This is a complication seen in intermediate uveitis, posterior uveitis, and panuveitis.

Although less serious, inflammatory cells, cellular debris and/or blood can invade the vitreous humor, which makes it cloudy. The vitreous humor is the clear gel-like substance that fills the eye. Normally, the vitreous gel is clear. This allows light through to the back of the eye. Rarely, inflammation from uveitis lets debris get into the vitreous. This may include blood and scar tissue. At first, this debris may cause floaters or flashes of light. If serious, it may block vision. Eye doctors will generally try medicines, and if the eye does not respond, the eye surgeon can remove the cloudy vitreous and replace it with a clear fluid. This procedure is called a vitrectromy.

High Eye Pressure and Glaucoma ► High Eye Pressure and Glaucoma ▼

High Eye Pressure and Glaucoma

These are possible complications of anterior uveitis, intermediate uveitis, posterior uveitis and panuveitis.

Your eye produces a watery fluid called aqueous humor, which goes into the eye and drains out. When your eye is healthy, the fluid drains through a mesh-like pathway and into the bloodstream. Aqueous fluid is produced by the ciliary body. It flows through the pupil and behind the clear cornea. Finally, it drains away through the trabecular meshwork.

The flow of aqueous humor through the front of the eye is related to overall pressure inside the eye. Inflammation caused by uveitis can lower production of aqueous humor. Inflammation can also lead to build-up of debris in the trabecular meshwork, blocking the flow of aqueous humor. Additionally, inflammatory cells are sticky and can also lead to blockage.

These problems can cause pressure in the eye to go up. This is called ocular hypertension. If the drainage is fully blocked, the pressure will rise dramatically. Severe pain, blurred vision and nausea are signs of this problem. It requires emergency room treatment. If the drainage is partly blocked, the pressure will go up – but not enough for the individual to feel it. Treatment involves the prescription of pressure-lowering eye drops. If the pressure cannot be controlled with pressure-lowering drops, it can lead to permanent vision loss – this is called glaucoma. Side vision (peripheral vision) is affected first. Many people do not notice loss of side vision until much of it is gone, so it is important to have your side vision tested regularly. Treatment includes the use of multiple eye drops; if this still does not control the damage caused by increased pressure, the eye doctor will recommend filtration surgery to let fluid drain from the eye. Long-term corticosteroid use (a common treatment for anterior uveitis, intermediate uveitis, posterior uveitis and panuveitis) is also a risk factor in the development of secondary glaucoma. The use of steroids can increase the amount of fluid produced by the ciliary body, causing the pressure inside the eye to rise. As many as one fifth of people with uveitis can develop ocular hypertension. Some of these individuals will develop glaucoma. The best way to prevent vision loss from glaucoma is by getting your eyes checked regularly. If you have glaucoma, you will need to work closely with your eye doctor to make your treatment successful. Find out more about preventing vision loss from glaucoma.

Uveitis and Cataracts ► Uveitis and Cataracts ▼

This is a complication of anterior uveitis, intermediate uveitis, posterior uveitis and panuveitis.

Cataracts are a common complication of uveitis. Cataracts are a clouding of the eye’s lens. In less developed countries, this can be one of the most common causes of vision loss. In industrialized nations, however, cataract surgery is a commonly performed procedure. There are few surgical complications and very few people go blind from the condition.

Eye doctors can remove the eye’s natural lens and replace it with a special plastic lens. However, if the cataracts are related to uveitis, eye doctors may not be able to perform surgery until the inflammation caused by uveitis is brought under control. In most cases, eye doctors want the eye to be free of inflammation for at least three months before performing cataract surgery. Sometimes, the artificial lens put in place by an eye doctor during cataract surgery can irritate the eye and cause anterior uveitis.

Long term use of corticosteroids used to treat uveitis can also increase the risk of developing cataracts. The type of cataract developed by long-term corticosteroid use causes the most visual disturbance.

Find out more about cataracts and cataract surgery.

Uveitis and Retinal Detachment ► Uveitis and Retinal Detachment ▼

This is a possible complication of posterior uveitis and panuveitis.

Uveitis can affect the vitreous body, the clear, gel-like substance that fills the eyeball. As we age, the vitreous may shrink and pull away from the retina. Sometimes, the retina can tear as the vitreous pulls away. If there is a break in the retina, vitreous may enter the tear and pull the retina away from the eye, requiring immediate surgery to prevent blindness. Floaters or flashes of light may be signs of vitreous detachment, a retinal tear or a retinal detachment. It’s important to see your eye doctor for a complete eye exam if you notice any signs of eye problems. For uveitis patients, the retinal detachment complication rate is generally less than 5%.