Episcleritis and Scleritis : A Cause of Red Eye
Red eye is a common symtomps in everyday medical practice. As a physician, we must be able to differentiate between the various etiologies of red eye. As study indicate that more than 40% of eye problem in developing country have red eye as its clinical symptomps.(1)
Episcleritis is defined as inflammation that happened in the area of episclera. This area is positioned above the sclera. Episcleritis and scleritis is two of the more uncommon cause of red eye. In episcleritis and scleritis, the red eye symptoms are not accompanied by decrease of visual acuity in the patients. To understand more about this clinical disease. First, we must see the histology of the area followed by the clinical manifestation and also the treatment of this condition.
Histology of Sclera
Sclera is considered one of the layer of the eye beside coroid and also retina layer. Sclera is classified as “tunica fibrosa” with other eye layer: cornea in eye histology. This means that sclera is considered as having outermost position in the eye. This area of the eye has less vascular tissue compared to the more inner part of the eye which is named tunica vasculosa and retina.
Sclera is similar and have continous surface with the cornea. The difference between this two is the transparency between those two surfaces. Sclera have whitish color compared to the transparent cornea and its conjunctiva. Sclera have many layers inside it, the layers of sclera are:
- Epithelial layer
- Episcleral tisue (and blood vessels inside it)
- Stroma (this part contain a lot of collagen tissue and fibroblast)
- Suprachoroid lamina (which contain many melanocytes)
Etiology of Sclera and Episclera Inflammation
The most common etiology of sclera and episclera inflammation is allergy. This immune system problem is also usually linked into more systemic clinical disease such as rheumatoid artritis. These diseases usually are not usually found in young children and is more commonly found in one of the eye.
Clinical Manifestation of Sclera and Episclera Inflammation
Episcleritis usually have much more milder clinical manifestation compared to scleritis. The clinical manifestation usually encompassed:
The red eye experienced by the patients, is usually caused by the conjunctiva blood vessel blockage. The red eye symptoms usually found is localized in one area of the eye. The redeye symptoms are usually shared with conjunctivitis. To differentiate these two symptoms we usually see the tarsal part of the conjunctiva. In episcleritis, the tarsal side of the eyelid is usually not affected. There is usually no secrete and no pain in giving pressure to the eyeball.
Photophobia is symptoms that is usually found in episcleritic patients, however this clinical symptoms is not usually as often found as the red eye. Photophobia is caused by the disturbance in the regulation of iris. Iris is important in regulating the pupil dilatation/constriction.
Usually the clinical symptoms of scleritis is much more severe than episcleritis. This is caused by the different of size between sclera and episclera. However, the patient compalins include pain and tenderness with touching of the periorbital region. There are several types of scleritis: diffuse scleritis, nodular scleritis and necrotic scleritis. These types of scleritis each have different clinical manifestation.
Diagnosis of the Disease
Beside looking at the condition, objective test is usually done with clinical chemistry examination. Clinical chemistry examination usually find RF (rheumatoid factor) that is usually also found on rheumatoid arthritis. Other test is usually done by checking the complete blood count of the body.
If the condition is not treated well, it will create a condition called scleromalasia perforans in which the sclera will be perforated. If this condition happened, it will be very painful for the patient. In addition, keratitis sclerotic, uveitis, and cataract may also appear. These complications may create visual disturbance in the patients. The visual disturbance may have many complication for the life of the patients.
The treatment for this condition is using topical steroid to reduce the inflammation of the sclera or episclera. If the patient is allergic to steroid, doctor may also prescribe non-steroidal anti inflammatory topical drug such as Na-Diklofenak that may have fewer side effects compared to the steroid one.
1.Hall D, Guyton J. Guyton physiology for medical students. 3rd ed. Philadelphia: Elsevier; 2007.
2. Vaughan J. Opthamology for Medical Student and Resident. 2nd ed. Vancouver: McGraw Hill;2008. p.72-75
3.Kumar D. Robbins Basic Pathology. 7th ed. Philadelphia: Elsevier;2008. p210-222