What Causes Vision Loss from Uveitis
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 vision loss.
High eye pressure and glaucoma
Inflammation caused by uveitis can cause pressure in the eye to go up. This is called ocular hypertension. In addition, long-term steroid use may cause 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 going to the eye doctor and following your treatment plan as directed.
Cataracts are a clouding of the eye’s lens. Eye doctors can remove the eye’s natural lens and replace it with a special artificial 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. In addition, long term use of corticosteroids for the treatment of uveitis can also increase the risk of developing cataracts.
Cystoid macular edema (CME)
This is a complication more commonly seen in intermediate uveitis, posterior uveitis, and panuveitis. CME is 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. It can cause decreased vision which may lead to permanent vision loss.
Damage to the Vitreous
This is a complication seen in intermediate uveitis, posterior uveitis, and panuveitis. The vitreous is the clear gel-like substance that fills 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.
This is a possible complication of posterior uveitis and panuveitis. Uveitis can increase the risk of developing a detached retina which will require immediate surgery to prevent blindness. As we age, the vitreous may shrink and pull away from the retina. This is called a vitreous detachment. Sometimes, the retina can pull off as the vitreous detaches. This is called a retinal detachment. Floaters or flashes of light may be signs of vitreous detachment or a retinal detachment.