Marginal Keratitis

Dr Ben Wild

Overview

The eyelids are made up of various types of skin, muscle, glands, hair follicles and much more. Their purpose is to protect the eyes from dryness, bright lights and irritants. As with skin everywhere on the body, the eyelid skin harbors bacteria. If the wrong type of bacteria colonize the eyelids or if there is an overgrowth of the normal bacteria, the eyelids can cause harm to the eyes. This harm can involve the cornea, the clear outermost layer of the eye in front of the colored iris, and the conjunctiva, the clear layer over the white part of the eye otherwise know as the sclera.

Frontal view of a healthy eye.

Marginal keratitis refers to a hypersentivity reaction within the cornea to the bacteria on the eyelids and is seen as white dots, representing colonies of white blood cells, around the edge of the cornea in red eyes. If left untreated, these white blood cells can cause scarring, ulceration, and/or blood vessel growth into the cornea. It is usually associated with blepharitis and/or rosacea.

Frontal view of a an eye with marginal keratitis.

Signs and Symptoms

Signs

White dots around the edge of the cornea in a red eye.

Symptoms

Mild to moderate discomfort, redness, tearing.

Causes and Risk Factors

Causes

Allergic hypersensitivity reaction to toxins created by the bacteria on the eyelids.

Risk factors

Blepharitis, rosacea, eczema.

Prevention and Treatment

Prevention

Daily eyelid hygiene.

Treatments

· Antibiotic eye drops and ointment.

· Steroid eye drops.

· Oral tetracycline pills.

Prognosis

Most cases of marginal keratitis are very easily managed through the aforementioned treatments. Without treatment, marginal keratitis can resolve on its own but is much more likely to cause permanent scarring, ulceration, blood vessel growth into the cornea. The causes of these conditions can usually be managed with proper lid hygiene but in some cases, need continuous treatment.