Episcleritis is inflammation of the episclera, which is the thin vascular outer coating of the eye wall, the sclera. Episclera lies underneath the more superficial layers of conjunctiva and other connective tissues. Unlike the more severe disease scleritis, episcleritis is a benign condition and is usually not associated with other systemic inflammatory diseases. The vessels that appear inflamed in either episcleritis or scleritis actually run through the episclera. It can appear in one section of or diffusely over the eye, or as a nodule of inflammation on the eye. It can occur in both eyes simultaneously, but more often occurs just in one, and almost never causes any permanent damage. Most often it is seen and treated by general ophthalmologists or even primary care physicians, unless the problem becomes more frequent or severe.
Redness is the main symptom of episcleritis. Patients will sometimes also complain of irritation or even burning. Symptoms can start and stop abruptly, and can recur often. Frank pain is not present and the eye should not be tender to the touch nor be significantly sensitive to light. Any of these symptoms suggest another disease process is taking place.
This is the most common point of confusion for most patients who have been afflicted by inflammation of the eye wall, and unfortunately, also for many eye care specialists who see these patients when their disease presents for the first time. Redness is common to both, but in episcleritis it involves the more superficial blood vessels in the conjunctiva and episclera, where as in scleritis it involves the deeper episcleral vessels. In episcleritis, this redness will mostly disappear when your ophthalmologist puts certain kinds of dilating eye drops in your eyes, but in scleritis, the deeper vessels will still appear red and inflamed despite use of these drops. Episcleritis is typically painless, or at best annoying. Pain and tenderness, however, are hallmarks of scleritis, especially pain that worsens with eye movement or radiates to different parts of the head, mimicking headache, sinus disease, or tooth ache. Bottom line: if the eye is significantly painful and red, it is probably something other than episcleritis.
Unfortunately, this is not known. It is thought to involve inflammation of the small vessels that run along the eye wall, a disease process known as microangiopathy, similar to scleritis. The level of inflammation present in episcleritis and the immunologic driving-force behind it are much less severe than in scleritis.
Episcleritis is usually not associated with any systemic disease. Only about 3 out of 10 people with episcleritis have an associated systemic disease. It can, however, present in a wide variety of conditions causing ocular surface inflammation, including connective tissue or vascular disease (such as lupus or rheumatoid arthritis), infection, rosacea, gout, or allergy. A work up is not always done for episcleritis unless it is more stubborn or severe.
Thankfully, episcleritis does not cause permanent damage to the eye. Rarely, it can be accompanied by mild inflammation of the peripheral cornea or inflammatory cells inside the eye. There are times, however, when a patient may later develop scleritis after first having episcleritis, and at that point vision threatening complications become a concern. Sadly, complications from episcleritis sometimes occur from treatment of episcleritis because of long term use of steroid eye drops.
Treatment of episcleritis is most often conservative. Observation without treatment may be all that is necessary for episcleritis that does not cause significant redness or irritation. Lubricating drops can help both soothe irritation as well as surface inflammation. More often a topical non-steroidal anti-inflammatory drug (NSAID) is used on a daily basis, either until symptoms resolve, or can be used safely long term in cases of recurrent episcleritis. Corticosteroid eye drops may help to relieve episcleritis but should never be relied on long term due to inevitable complications of cataracts and glaucoma. If episcleritis is particularly stubborn or severe, oral NSAID therapy can be used. Eye redness, irritation, or pain requiring treatment more aggressive than this should be reevaluated by a specialist for the presence of a more serious disease process, like scleritis.