Because the outside of the eye is in direct contact with the environment, it is susceptible to infections and injuries. There are also a number of hereditary diseases that can impact the outer eye. Common signs of external eye disease are redness, irritation, watering, and blurry vision.
Conjunctivitis is a very common external eye disease and is often referred to as pink eye. Conjunctivitis is an inflammation of the clear lining of the surface of the eye that causes red eyes, discomfort, and tearing. Conjunctivitis can be caused by viruses, bacteria, and allergic reactions, among other things. The appropriate treatment depends on the cause, and should be evaluated by an ophthalmologist.
Blepharitis (eyelid inflammation) is also a common external disease. Blepharitis can cause irritation, watering, red eyes, itching, and predispose patients to develop styes and chalazia (styes that do not go away). Blepharitis can be caused by bacteria or other organisms, but is often due the way that the normal glands of the eyelid produce oil. Because of this, patients often need to have an individualized treatment plan to control their inflammation.
Episcleritis and Scleritis
Other common conditions include inflammation of the sclera (the tough white outer layer of the eye) and inflammation of the episclera (the lining between the sclera and the conjunctiva).
Episcleritis typically causes redness and irritation and can be treated with drops or a mild anti-inflammatory pill such as ibuprofen. Scleritis is a more severe condition that causes redness, deep pain, blurred vision, or even permanent injury to the eye. Scleritis can be caused by an underlying medical condition such as rheumatoid arthritis or lupus. Due to this, a full medical evaluation with blood work is usually necessary for scleritis. Treatment for scleritis varies and may include drops and/or oral anti-inflammatory medication such as prednisone. If it is caused by a medical condition, then that disease should be addressed as well.
A common external eye injury is a corneal abrasion, or damage to the thin outer layer of the cornea. It is usually caused by a scratch from a tool, twig, fingernail, contact lens, or some other object. A severely dry eye can also cause an abrasion. Symptoms include pain, blurred vision, redness, light sensitivity, and watering. Most corneal abrasions heal quickly and are usually treated with antibiotic eye drops or ointment. All abrasions should be evaluated by an ophthalmologist to determine the cause.