What Is Scleritis?
Scleritis is a disorder in which the outer surface of the eye becomes severely inflamed. The sclera is the outer protective layer of the eye. In scleritis, the scleral tissue becomes inflamed and red. The condition can be very painful.
Scleritis is believed to be the result of the body’s immune system overreacting. The types of scleritis are divided by the position where inflammation is taking place: anterior (front) or posterior (rear). Most individuals feel severe pain with the condition, but there are exceptions.
Treatment is a step-ladder approach beginning with the least risk and moving on as the condition worsens. Outlook depends upon the type of scleritis. In necrotizing scleritis, which is the most dangerous type, complete or partial vision loss is common.
Risk Factors of Scleritis
Scleritis may occur in any age group. Women have twice the risk of men for developing the disease. There is no particular prevalence for the disease in a specific race or geographic area.
There are certain diseases that have an increase in the incidence of scleritis:
- Wegener’s disease: up to seven percent of patients will develop scleritis; also called Wegener’s granulomatosis, it involves inflammation of the blood vessels (Galor & Thorne, 2007)
- rheumatoid arthritis (RA): autoimmune disorder causing inflammation of the joints
- inflammatory bowel disease (IBD): disease that causes digestive symptoms resulting from inflammation of the bowel
Cause of Scleritis
The T cells of the immune system are theorized to 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. In scleritis, they are believed to begin attacking the eye’s own scleral cells.
Classification of Scleritis
Doctors use what is called the Watson and Hayreh classification to distinguish different types of scleritis (Gaylor & Thorne, 2007). 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.
Subtypes of anterior scleritis include:
- diffuse anterior scleritis: most common form of scleritis
- nodular anterior scleritis: second most common form of scleritis
- necrotizing anterior scleritis with inflammation: most serious form of anterior scleritis
- necrotizing anterior scleritis (without inflammation): rarest form of anterior scleritis
Posterior scleritis is the more difficult form to diagnose. 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.
Symptoms of Scleritis
Pain which responds poorly to painkillers is the predominant symptom of those with scleritis. Eye movements are only likely to make the pain worse. The pain may spread throughout the entire face.
Up to 20 percent of patients suffer little to no pain. (Galor & Thorne, 2007) The reasons this may occur include:
- milder case of scleritis
- patients on immunosuppressive medications prior to symptoms beginning (their body is already keeping the suppressing the T cells from overreaction)
- scleromalacia perforans (a rare complication of advanced rheumatoid arthritis, or RA)
Symptoms of posterior scleritis include:
- deep-seated headaches
- pain upon eye movement
- double vision
Other symptoms may include:
- decreased vision
- photophobia (sensitive to light)
Diagnosis of Scleritis
Detailed clinical history, examination, and laboratory evaluations are used in diagnosis.
Doctors may ask questions regarding a patient’s history of systemic conditions (RA, Wegener’s granulomatosis, IBD), as well as the history of trauma or surgery to the eye.
The different diagnoses for scleritis include:
- episcleritis (inflammation of superficial vessels in the outer most layer of the clear or episclera)
- blepharitis (inflammation of the outer eye lid)
- viral/bacteria conjunctivitis (inflammation of the eye by bacteria or virus)
The following tests can help make a diagnosis:
- ultrasonography: looks for changes occurring in or around the sclera
- complete blood count: checks for sign of infection and immune system activity
- sclera biopsy: removal of sclera tissue for microscopic examination
Treatment of Scleritis
Treatment of scleritis focuses on fighting the inflammation before it can cause permanent damage. The treatment follows an upward-step approach. If the first step in medication fails, then the second is used and so forth.
Medications for the treatment of scleritis include:
- nonsteroidal anti-inflammatory drugs (NSAIDs) (most often used in nodular anterior scleritis)
- oral glucocorticoids (preferred choice for posterior scleritis)
- immunosuppressive drugs with oral glucocorticoids (preferred for the most dangerous form, necrotizing scleritis)
Outlook of Scleritis
Cases of sclerititis are capable of causing significant eye damage. The disorder is not uncommon for causing partial to complete vision loss. When vision loss does occur, it is normally from a result of necrotizing scleritis.