Scleritis is a serious inflammatory

disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

that affects the white outer coating of the eye, known as the sclera. The disease is often contracted through association with other diseases of the body, such as granulomatosis with polyangiitis or rheumatoid arthritis. There are three types of scleritis: diffuse scleritis (the most common), nodular scleritis, and necrotizing scleritis (the most severe). Scleritis may be the first symptom of onset of

connective tissue disease A connective tissue disease (collagenosis) is any disease that has the connective tissues of the body as a target of pathology. Connective tissue is any type of biological tissue with an extensive extracellular matrix that supports, binds togeth ...

. Episcleritis is inflammation of the

episclera The episclera is the outermost layer of the sclera (the white of the eye).Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company, 1990. It is composed of loose, fibrous, elastic tissue and attac ...

, a less serious condition that seldom develops into scleritis.

Signs and symptoms

Symptoms of scleritis include: *Redness of the sclera and conjunctiva, sometimes changing to a

purple Purple is any of a variety of colors with hue between red and blue. In the RGB color model used in computer and television screens, purples are produced by mixing red and blue light. In the RYB color model historically used by painters, ...

hue *Severe ocular pain, which may radiate to the temple or jaw. The pain is often described as deep or boring. *

Photophobia Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of ...

and

tearing Tearing is the act of breaking apart a material by force, without the aid of a cutting tool. A tear in a piece of paper, fabric, or some other similar object may be the result of the intentional effort with one's bare hands, or be accidental. U ...

*Decrease in visual acuity, possibly leading to blindness The pain of episcleritis is less severe than in scleritis. In hyperemia, there is a visible increase in the blood flow to the sclera (

hyperaemia Hyperaemia (also hyperemia) is the increase of blood flow to different tissues in the body. It can have medical implications but is also a regulatory response, allowing change in blood supply to different tissues through vasodilation. Clinically, ...

), which accounts for the redness of the eye. Unlike in conjunctivitis, this redness will not move with gentle pressure to the conjunctiva.

Complications

Secondary keratitis or uveitis may occur with scleritis. The most severe complications are associated with necrotizing scleritis.

Pathophysiology

Most of the time, scleritis is not caused by an infectious agent. Histopathological changes are that of a chronic granulomatous disorder, characterized by fibrinoid necrosis, infiltration by polymorphonuclear cells, lymphocytes, plasma cells and macrophages. The granuloma is surrounded by multinucleated epitheloid giant cells and new vessels, some of which may show evidence of vasculitis.

Diagnosis

Scleritis is best detected by examining the sclera in daylight; retracting the lids helps determine the extent of involvement. Other aspects of the eye exam (i.e. visual acuity testing, slit lamp examination, etc.) may be normal. Scleritis may be differentiated from episcleritis by using

phenylephrine Phenylephrine is a medication primarily used as a decongestant, to dilate the pupil, to increase blood pressure, and to relieve hemorrhoids. In the United States, it was previously used orally as an over-the-counter decongestant to relieve nas ...

eye drops, which causes blanching of the blood vessels in episcleritis, but not in scleritis. Ancillary tests CT scans,

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves ...

s, and ultrasonographies can be helpful, but do not replace the physical examination.

Classification

Scleritis can be classified as anterior scleritis and posterior scleritis. Anterior scleritis is the most common variety, accounting for about 98% of the cases. It is of two types : Non-necrotising and necrotising. Non-necrotising scleritis is the most common, and is further classified into diffuse and nodular type based on morphology. Necrotising scleritis accounts for 13% of the cases. It can occur with or without inflammation.

Treatment

Medical

In mild to moderate cases of scleritis, non-steroidal anti-inflammatory drugs such as flurbiprofen, indomethacin or ibuprofen may be prescribed for pain relief. Systemic corticosteroids like prednisolone may be used if NSAIDs are inappropriate or scleritis is posterior or necrotizing. Periocular steroid injections may be used in non-necrotizing scleritis, but it is contraindicated in necrotizing disease. If disease control is inadequate with steroids alone, immunosuppressives (Eg: cyclophosphamide,

azathioprine Azathioprine (AZA), sold under the brand name Imuran, among others, is an immunosuppressive medication. It is used in rheumatoid arthritis, granulomatosis with polyangiitis, Crohn's disease, ulcerative colitis, and systemic lupus erythematosus, ...

, methotrexate) and/or immunomodulators may be considered for treatment. In infective scleritis, if infective agent is identified, topical or systemic

antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention o ...

may be prescribed.

Surgical Intervention

Surgery may be indicated if scleral perforation or excessive scleral thinning is present. Bandage contact lens or corneal glue may be used to repair damaged corneal tissue in the eye and preserve the patient's vision. If not treated, scleritis can cause blindness.

Epidemiology

Scleritis is not a common disease, although the exact prevalence and incidence are unknown. It is somewhat more common in women, and is most common in the fourth to sixth decades of life.

References

*Rosenbaum JT. The Eye and rheumatic diseases. In: Firestein GS, Budd RC, Harris ED Jr, ''et al.'', eds. Kelley's Textbook of Rheumatology. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 46. *Watson P. Diseases of the sclera and episclera. In: Tasman W, Jaeger EA, eds. Duane’s Ophthalmology. 15th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2009:chap 23.

External links

{{Eye pathology Disorders of sclera and cornea Inflammations Steroid-responsive inflammatory conditions