Episcleritis is inflammation of the thin layer covering the white part of the eye and usually follows a mild course. Scleritis is a serious condition affecting deeper tissues that can cause severe pain and vision loss. Distinguishing between the two conditions is highly important for treatment planning.
Episcleritis is generally associated with allergies, infections, or connective tissue diseases. Mild redness, stinging, and pain are the most common symptoms. It often resolves on its own, but recurrent cases require evaluation by an ophthalmologist.
Scleritis may develop due to rheumatic diseases, autoimmune disorders, or infections. It causes severe pain, light sensitivity, and reduced vision. If left untreated, it may lead to permanent vision loss.
Topical eye drops are generally sufficient for episcleritis, while corticosteroids or immunosuppressive medications may be required for scleritis. Accurate diagnosis and early treatment are critical for preventing complications.
Episcleritis and scleritis are two different conditions caused by inflammation involving the scleral tissue on the outer part of the eye. Episcleritis is a mild and generally painless inflammation of the layer close to the surface of the sclera. Scleritis is a more serious and painful inflammation affecting the deeper layers. Scleritis is generally associated with connective tissue diseases and requires treatment, while episcleritis can often resolve spontaneously.
The eye consists of several layers. The outermost layer is the firm white layer known as the sclera. Immediately above the sclera is a thinner, highly vascular tissue called the episclera. Episcleritis is inflammation of this thin outer layer. Scleritis is inflammation of the deeper, firm white layer, which is the sclera itself. The layer in which the inflammation occurs completely changes the symptoms and treatment.
The episcleral layer is close to the surface and contains many small blood vessels. When these vessels become inflamed, they dilate and give the eye a bright red or pink appearance. These superficial vessels may constrict when a special eye drop containing phenylephrine is applied, reducing the redness. Scleritis affects the deeper sclera. Because the inflammation involves deeper blood vessels, the redness usually appears darker and more purplish. These deeper vessels do not constrict with phenylephrine drops.
Yes, the most common type of episcleritis is simple episcleritis. In this condition, redness and vascular congestion occur in the white part of the eye without a distinct swelling or nodule. The redness may affect only one section of the eye, known as sectoral episcleritis, or spread across a wider area, known as diffuse episcleritis. It generally begins suddenly and is usually accompanied by mild discomfort.
Nodular episcleritis is less common than the simple type. A small, raised lump called a nodule forms in the inflamed area. This nodule may be slightly tender to the touch. Compared with simple episcleritis, it may begin more gradually, last longer, and cause slightly greater discomfort. Nodular episcleritis is also somewhat more likely to be associated with another condition elsewhere in the body.
Most cases of scleritis, approximately 90%, affect the front part of the eye. This is called anterior scleritis. It is inflammation of the sclera in front of the points where the eye muscles attach to the white part of the eye. Anterior scleritis has several types, and the severity of the condition varies between them.
Diffuse anterior scleritis is the most common and generally mildest type of anterior scleritis. It accounts for approximately half of all scleritis cases. This type causes widespread redness and swelling in the white part of the eye. Pain may occur but is generally more manageable than in other types of scleritis. It carries a lower risk of threatening vision and usually responds well to treatment.
Nodular anterior scleritis accounts for approximately 15% to 40% of scleritis cases. In this type, one or more tender, red, firm nodules that do not move develop in the sclera. Pain is generally more pronounced than in the diffuse type. An important risk is that it may progress over time to the more serious necrotizing form of scleritis, which causes tissue damage. It also tends to recur frequently.
Necrotizing anterior scleritis is the most serious and dangerous form of scleritis. Severe, unbearable, boring pain is typical. This type causes significant tissue damage, thinning, and destruction, known as necrosis, in the sclera. The dark vascular layer beneath the thinned sclera, known as the choroid, may become visible. There is even a risk of perforation of the eyeball. It is generally associated with a serious underlying systemic disease, particularly vasculitis, and requires urgent, intensive treatment.
This is a very rare, specialized form of scleritis. Its most surprising feature is that, unlike other types of scleritis, severe pain is absent or minimal. It begins insidiously and progresses slowly, causing marked thinning of the sclera. The white part of the eye appears to melt away, exposing the tissues underneath. It occurs almost exclusively in women with long-standing, advanced rheumatoid arthritis. The absence of pain may delay diagnosis, but the condition is very serious.
Posterior scleritis is inflammation of the sclera at the back of the eyeball and is quite rare. The main difficulty is that the front of the eye may look completely normal and white. This makes diagnosis more difficult. However, patients generally experience pain that worsens with eye movements, blurred vision, or vision loss. Specialized imaging methods, particularly ocular ultrasonography, are essential for diagnosis.
In most cases of episcleritis, approximately two-thirds, no specific underlying cause can be identified. This is called idiopathic episcleritis. Inflammation occurs only in the episcleral layer of the eye without another problem elsewhere in the body. It is generally harmless and resolves spontaneously.
Yes, although uncommon, certain infections may trigger episcleritis. Infections such as shingles caused by herpes zoster, which produces a rash around the eye or on the face, herpes simplex, syphilis, tuberculosis, Lyme disease, or cat-scratch disease may sometimes cause episcleritis. However, these causes are much less common than idiopathic episcleritis.
The situation with scleritis is very different from episcleritis. More than half of scleritis cases are associated with a serious underlying systemic disease. Rheumatic diseases, connective tissue diseases, and vasculitis are particularly closely associated with scleritis. Sometimes scleritis may even be the first sign of the serious underlying condition. Therefore, when scleritis is diagnosed, the presence of an underlying disease must be investigated.
Infections may also cause scleritis, but this is less common than scleritis associated with autoimmune disease and accounts for approximately 5% to 10% of all cases. Bacteria, viruses, particularly the shingles virus, fungi, or parasites may cause scleritis. The risk of infection is particularly higher in scleritis that develops after eye surgery, known as surgically induced necrotizing scleritis (SINS). Distinguishing infectious scleritis from other types is extremely important because its treatment is completely different and immunosuppressive medications cannot be used.
Rheumatoid arthritis (RA) is an autoimmune joint disease that may be associated with both episcleritis and scleritis. However, the association is much stronger and more important for scleritis. Although episcleritis may sometimes occur in patients with RA, scleritis is one of the more serious ocular manifestations of the disease. Necrotizing scleritis and the painless form known as scleromalacia perforans are particularly associated with advanced RA. Patients with RA have a higher risk of developing scleritis than the general population.
Vasculitis refers to serious systemic diseases involving inflammation of the blood vessels. Conditions such as granulomatosis with polyangiitis (GPA) and polyarteritis nodosa (PAN) are strongly associated with scleritis. Scleritis may even be the first sign of these potentially life-threatening diseases. Scleritis associated with vasculitis is generally the most severe necrotizing form and requires urgent treatment. Episcleritis may also sometimes be associated with vasculitis, but this is less common than with scleritis.
In addition to rheumatoid arthritis and vasculitis, many other systemic diseases may be associated with episcleritis or scleritis. These include systemic lupus erythematosus (SLE), inflammatory bowel diseases such as Crohn's disease and ulcerative colitis, ankylosing spondylitis, psoriatic arthritis, Sjögren's syndrome, sarcoidosis, and gout. Infectious diseases such as tuberculosis and syphilis may also be associated, particularly with scleritis. These associations are more common and pronounced in scleritis.
Pain is one of the most important clues for distinguishing between these two conditions. Episcleritis generally causes no pain or only mild discomfort, stinging, aching, or tenderness. Severe pain is not expected. Scleritis is the opposite. It generally causes severe, deep, boring pain that feels as though it penetrates the eye and may spread to the head, face, or forehead. The pain may wake the person from sleep at night. The only exception is the painless type known as scleromalacia perforans.
Both conditions cause eye redness, but their appearance differs. In episcleritis, the redness is generally brighter and appears vivid red or pink. The superficial blood vessels become prominent. In scleritis, the inflammation is deeper, so the redness is generally darker, duller, purplish, or bluish red. The color and tone of the redness are important findings that the physician considers during differential diagnosis.
The effect on vision is another important difference. Episcleritis generally does not affect visual acuity. A person with an episcleritis flare usually continues to see clearly. Scleritis frequently impairs vision. Blurred vision or reduced visual acuity is a common symptom of scleritis. This indicates that scleritis may affect deeper structures that are important for vision, including the cornea, lens, retina, and optic nerve, and reflects the seriousness of the condition.
A detailed eye examination by a physician is essential for an accurate diagnosis. After listening to your symptoms, your physician will examine your eye using a special microscope called a slit lamp. This examination evaluates whether the inflammation is superficial or deep, the structure and color of the blood vessels, whether any nodules are present, whether other parts of the eye such as the cornea, intraocular fluid, and lens are affected, and the intraocular pressure. These findings play a critical role in distinguishing episcleritis from scleritis.
Phenylephrine is a substance that constricts blood vessels. Your physician may apply this drop to your eye during the examination. If the inflammation involves superficial blood vessels, as in episcleritis, these vessels constrict and the redness decreases markedly within 10 to 15 minutes, making the eye appear whiter. If the inflammation involves deeper blood vessels, as in scleritis, phenylephrine does not affect them and the redness persists. This simple test provides a valuable clue for distinguishing between the two conditions.
If you are experiencing a first episode of simple episcleritis, additional tests such as blood tests are generally unnecessary. However, if episcleritis recurs frequently or is nodular, certain blood tests may be requested because an underlying cause may be present. The situation is different with scleritis. Because more than half of scleritis cases are associated with a systemic disease, performing comprehensive blood tests to investigate or rule out an underlying disease such as a rheumatic condition or vasculitis is standard practice in almost everyone diagnosed with scleritis.
Imaging methods are not routinely used to diagnose anterior scleritis or episcleritis. However, imaging is very important if posterior scleritis is suspected or the diagnosis is uncertain. B-scan ultrasonography is particularly valuable for showing thickening of the posterior sclera, fluid accumulation around it, and possible complications such as retinal detachment. In rare cases, MRI or CT may also be used to confirm the diagnosis or rule out other conditions.
Conjunctivitis, also known as pink eye, is the most common cause of eye redness. However, it has several important differences from episcleritis and scleritis. Conjunctivitis generally causes crusting or watery discharge, while discharge is not typical in episcleritis or scleritis. Pain in conjunctivitis is generally experienced as stinging, burning, or itching, while the pain of scleritis is much more severe and deeper. The redness in episcleritis is generally more localized than in conjunctivitis.
Uveitis is inflammation of the uveal layer inside the eye, which includes the iris, ciliary body, and choroid. Scleritis is inflammation of the outer white part of the eye. In uveitis, the inflammation is inside the eye, and findings such as cells in the anterior chamber and deposits on the back of the cornea can be seen during the examination. In scleritis, the inflammation is located within the sclera itself. However, scleritis and uveitis may sometimes occur together. Pain and light sensitivity may occur with both conditions, but the examination findings differ.
Because episcleritis is generally a benign condition, treatment begins with simple measures. As most cases resolve on their own, observation alone may sometimes be sufficient. Applying a cold compress or using artificial tears recommended by your physician may provide relief. Keeping these drops in the refrigerator may create a cooling effect when they are applied. If the symptoms are mild, these supportive measures are generally sufficient.
If supportive treatment is insufficient or the symptoms are bothersome, your physician may recommend eye drops. The first option is generally anti-inflammatory drops containing an NSAID, such as diclofenac or ketorolac. If these are insufficient or the condition is more severe, corticosteroid eye drops may be used. Corticosteroid drops are more effective but may cause adverse effects such as elevated intraocular pressure. They must therefore be used under medical supervision and gradually tapered before being discontinued.
Oral medications are generally not the first choice for treating episcleritis. However, in persistent cases that do not respond to eye drops, particularly nodular episcleritis, your physician may prescribe oral NSAID anti-inflammatory medications such as ibuprofen or naproxen. Oral corticosteroids are very rarely required for episcleritis alone and are generally considered when another underlying systemic disease is present.
Because scleritis is much more serious than episcleritis and can potentially threaten vision, its treatment is also more intensive and must be managed by an ophthalmologist. Scleritis generally cannot be treated with eye drops alone because the inflammation is deeper. The aims of treatment are to control pain, suppress inflammation, prevent tissue damage, and treat any underlying disease. Treatment generally requires stronger medications used over a longer period.
Oral medications usually form the basis of scleritis treatment. High-dose NSAIDs such as indomethacin or naproxen are frequently used as first-line treatment. If these are insufficient or the scleritis is severe, particularly in necrotizing or posterior scleritis, treatment is changed to oral corticosteroids such as prednisone. Corticosteroids are generally started at a high dose and reduced very gradually as the condition responds. Careful monitoring is essential because of the adverse effects associated with long-term corticosteroid use.
Immunosuppressive medications play an important role in the treatment of scleritis. They are particularly needed in patients who do not respond to NSAIDs and corticosteroids, whose corticosteroid dose cannot be reduced, who experience frequent recurrences, or who have a serious underlying rheumatic condition such as RA or vasculitis. Medications such as methotrexate, azathioprine, and cyclophosphamide or newer biological agents such as TNF inhibitors and rituximab may be used. These treatments are generally managed jointly by an ophthalmologist and a rheumatologist.
If an infection is identified as the cause of scleritis, the treatment changes completely. Corticosteroids or immunosuppressive medications may worsen the infection in this situation. Treatment must target the microorganism causing the infection. Antibiotics are used for bacterial infections, antifungal medications for fungal infections, and antiviral medications for viral infections such as shingles. These medications may be administered as eye drops, orally, or sometimes intravenously, and treatment is generally prolonged.
Surgery is rarely required in the treatment of scleritis. However, in necrotizing scleritis, the most serious form, urgent surgery may be necessary to preserve the integrity of the eye if severe scleral thinning or perforation develops. A patch graft is sutured over the thinned area to reinforce the scleral wall. This is an essential intervention performed to preserve vision.
Both episcleritis and scleritis may recur. Treatment of scleritis is generally prolonged, and regular medication use and attendance at follow-up appointments are very important. Close monitoring is particularly necessary because of the potential adverse effects of corticosteroids and immunosuppressive medications. If an underlying systemic disease is present, treating it also plays a critical role in controlling scleritis. Good outcomes are possible in both conditions with early diagnosis and appropriate treatment, but scleritis requires more careful and persistent follow-up.
