CORNEAL DISEASES and ULCER – Causes and Risk Factors, Clinical Manifestations and Management
CORNEAL DISEASES and ULCER – Causes and Risk Factors, Clinical Manifestations and Management
CORNEAL DISEASES
KERATITIS
Keratitis is an inflammation or infection of the cornea, the front part of the eye. It can be superficial or deep, acute or chronic.
a. Keratitis has multiple causes, one of which is an infection from bacteria (staphylococcus aureus and Pseudomonas aeruginosa), virus (herpes simplex, herpes zoster and adeno virus) and intense ultraviolet radiation exposure, colonization of gram negative bacteria on contact lenses and upper respiratory infection, involving cold sores.
b. Superficial keratitis involves the epithelium and superficial layers of the cornea. After healing, this form of keratitis does not generally leave a scar
Deep keratitis involves deeper layers of the cornea, and the natural course leaves a scare upon healing that impairs vision if one or near the visual axis.
CLINICAL MANIFESTATIONS
- Pain
- Redness
- Blepharospasm
- Foreign body sensation
- Photophobia
- Increased tearing
- Difficulty opening eye
MANAGEMENT
Treatment includes administration of antibiotic eye drops every 30 minutes around the clock for the first few days, then every 1-2 hours and eye patched for 24 hours. Systemic antibiotics may be administered. Local application of atropine sulphate 1% ointment twice daily. Cycloplegic drugs are administered to reduce pain caused by ciliary spasm. In addition, contact lens wearers are typically advised to discontinue contact lens wear and discarding contaminated contact lenses and contact lens cases. Steroid containing medications should not be used for bacterial infections, as they may exacerbate the disease and lead to severe corneal ulceration and corneal perforation. Penetrating keratoplasty is indicated for corneal scarring and must be performed when the herpetic disease has been inactive for many years.
CORNEAL ULCER
A corneal ulcer, or ulcerative keratitis, or eyesore is an inflammatory or more seriously, infective condition of the cornea involving disruption of its epithelial layer with involvement of the corneal stroma. It is a common condition in humans particularly in the tropics and the agrarian societies. In developing countries, children afflicted by Vitamin A deficiency are at high risk for corneal ulcer and may become blind in both eyes, which may persist lifelong.
CAUSES AND RISK FACTORS
- Corneal ulcers are a common human eye disease. They are caused by trauma, particularly with vegetable matter, as also chemical injury, contact lenses and infections.
- Eye conditions can cause corneal ulcers, such as entropion, distichiae, corneal dystrophy, and keratoconjunctivitis sicca (dry eye)
- Bacterial infections: Staphylococcus aureus, Streptococcus viridians, Pseudomonas, E.coli, Enterococci, and many other bacteria cause corneal ulcers and are common in people who wear contact lenses.
- Viral infections: Viral keratitis causes corneal ulceration. It is caused most commonly by Herpes simplex, Herpes Zoster, varicella virus and adenoviruses.
- Fungal Infections: It is caused by Aspergillus sp., Fusarium sp., Candida sp., as also Rhizopus, Mucor, and other fungi can cause corneal ulcers.
- Tiny tears to the corneal surface may become infected and lead to corneal ulcers
- Disorders that affect the eyelid and prevent your eye from closing completely, such as Bell’s palsy, can dry your cornea and make it more vulnerable to ulcers.
- Chemical burns or other caustic (damaging) solution splashes can injure the cornea and lead to corneal ulceration
- People who wear contact lenses are at an increased risk of corneal ulcers. Contact lenses may damage your cornea in many ways: scratches on the edge of your contact lens can scrape the cornea’s surface and make it more vulnerable to bacterial infections and wearing lenses for extended periods of time can also block oxygen to the cornea, making it more susceptible to infections.
CLINICAL MANIFESTATIONS
- Red eye
- Pain in the eye
- Feeling that something is in eye
- Lacrimation
- Pus or thick discharge draining from your eye
- Headache and blurring of vision
- Photophobia
- Pain when looking at bright lights
- Swollen eyelids
- Vision loss
- A white or gray round spot on the cornea that is visible with the naked eye if the ulcer is large.
MANAGEMENT
Proper diagnosis is essential for optimal treatment. Bacterial corneal ulcer requires intensive fortified antibiotic therapy to treat the infection. Fungal corneal ulcers require intensive application of topical anti-fungal agents. Viral corneal ulceration caused by herpes virus may respond to antiviral like topical acyclovir ointment instilled at least five times a day. Alongside, supportive therapy like pain medications are given, including topical cycloplegics like atropine or homatropine to dilate the pupil and thereby stop spasms of the ciliary muscle. Superficial ulcers may heal in less than a week. Deep ulcers and descemetoceles may require conjunctival grafts or conjunctival flaps, soft contact lenses, or corneal transplant. Proper nutrition, including protein intake and vitamin C are usually advised. In cases of keratomalacia, where the corneal ulceration is due to a deficiency of vitamin A, supplementation of the vitamin A by oral or intramuscular route is given. Drugs that are usually contraindicated in corneal ulcer are topical corticosteroids and anesthetics - these should not be used on any type of corneal ulcer because they prevent healing, may lead to super infection with fungi and other bacteria and will often make the condition much worse. Hospitalization may be required if the ulcer is severe.
PREVENTION
- Wear eye protection when exposed to small particles that can enter your eye
- If you have dry eyes or if your eyelids do not close completely, use artificial teardrops to keep your eyes lubricated
- If you wear contact lenses, be extremely careful about the way you clean and wear your lenses.
- Store the lenses in disinfecting solutions overnight
- Always wash your hands before handling the lenses. Never use saliva to lubricate your lenses because your mouth contains bacteria that can harm your cornea.
- Remove your lenses from your eyes every evening and carefully clean them. Never use tap water to clean the lenses
- Apply cool compresses to the affected eye. Do not touch or rub your eye with your fingers
- Remove your lenses whenever your eyes are irritated and leave them out until your eyes feel better. Never sleep with your contact lenses in your eyes.
- Limit spread of infection by washing your hands often and drying them with a clean towel.
- Regularly clean your contact lens case