The sclera is the protective outer layer of the eye. Scleritis is a disorder in which the sclera becomes severely inflamed and red. The condition can be very painful.
Scleritis is believed to be the result of the body’s immune system overreacting. Which type of scleritis you have depends on the location of the inflammation. Anterior scleritis occurs in the front of the eye, and posterior scleritis occurs in the back of the eye. Most people feel severe pain with the condition, but there are exceptions.
Treatment begins with the lowest risk option and progresses to riskier options as the condition worsens. Your outlook depends on the type of scleritis. In necrotizing scleritis, which is the most dangerous type, complete or partial vision loss is common.
Severe eye pain that responds poorly to painkillers is the main symptom of scleritis. Eye movements are likely to make the pain worse. The pain may spread throughout the entire face.
Some people experience little to no pain from scleritis. This may be because they have:
- a milder case of scleritis
- scleromalacia perforans, which is a rare complication of advanced rheumatoid arthritis, or RA
- a history of using immunosuppressive medications before their symptoms began
The symptoms of posterior scleritis include:
- deep-seated headaches
- pain caused by eye movement
- double vision
Other symptoms may include:
- lacrimation, or excessive tearing
- decreased vision
- photophobia, or sensitivity to light
There are theories that the immune system’s T cells cause scleritis. The immune system is a network of organs, tissues, and circulating cells that work together to stop bacteria and viruses from causing illness. T cells work to destroy incoming pathogens, which are organisms that can cause disease or illness. In scleritis, they’re believed to begin attacking the eye’s own scleral cells.
Scleritis may occur at any age. Women have twice the risk as men for developing it. There’s no specific race or area of the world where this disease is more common.
You have an increased chance of developing scleritis if you have:
- Wegener’s disease (Wegener’s granulomatosis), which is an uncommon disorder that involves inflammation of the blood vessels
- rheumatoid arthritis (RA), which is an autoimmune disorder causing inflammation of the joints
- inflammatory bowel disease (IBD), which is a disease that causes digestive symptoms due to inflammation of the bowel
Doctors use what’s called the Watson and Hayreh classification to distinguish the different types of scleritis. Classification is based upon whether the disease is affecting the anterior or posterior of the sclera. The anterior forms are most likely to have an underlying illness as part of their cause.
The subtypes of anterior scleritis include:
- diffuse anterior scleritis, which is the most common form of scleritis
- nodular anterior scleritis, which is second most common form of scleritis
- necrotizing anterior scleritis with inflammation, which is the most serious form of anterior scleritis
- necrotizing anterior scleritis without inflammation, which is the rarest form of anterior scleritis
Posterior scleritis is more difficult to diagnose. In this type, the sclera inflammation is harder to detect because it has variable symptoms, including many that mimic other disorders. Symptoms include severe irritation of the eye and eye pain.
Your doctor will review a detailed medical history, perform an examination, and perform laboratory evaluations to diagnose scleritis.
Your doctor may ask questions about your history of systemic conditions, such as whether you’ve had RA, Wegener’s granulomatosis, or IBD They may also ask if you’ve had a history of trauma or surgery to the eye.
Other conditions that have symptoms similar to scleritis include:
- episcleritis, which is an inflammation of superficial vessels in the outermost layer of the eye (episclera)
- blepharitis, which is an inflammation of the outer eye lid
- viral conjunctivitis, which is an inflammation of the eye caused by a virus
- bacterial conjunctivitis, which is an inflammation of the eye caused by bacteria
The following tests can help your doctor make a diagnosis:
- They can use ultrasonography to look for changes occurring in or around the sclera.
- They can get a complete blood count to check for signs of infection and immune system activity.
- They can take biopsy of your sclera, which involves removing tissue of the sclera so that it can be examined under a microscope.
Treatment of scleritis focuses on fighting the inflammation before it can cause permanent damage. The treatment follows a stepladder approach. If the first step in medication fails, then the second is used and so forth.
Medications used to treat scleritis include the following:
- Nonsteroidal anti-inflammatory drugs are most often used in nodular anterior scleritis.
- Oral glucocorticoids are the preferred choice for posterior scleritis.
- Immunosuppressive drugs with oral glucocorticoids are preferred for the most dangerous form, which is necrotizing scleritis.
Scleritis can cause significant eye damage. This disorder can also result in partial to complete vision loss. When vision loss does occur, it’s usually the result of necrotizing scleritis.