Filamentary Keratitis

Dr Ben Wild

Overview

Dry eye represents a breakdown of the complex interplay between tear volume, tear film stability (evaporation), inflammation, and eyelid function. The lacrimal gland produces most of the watery (aqueous) portion of the tears responsible for oxygen transmission, removal of debris, and antimicrobial activity. The meibomian glands, located along the edges of the eyelids, produce the oil (lipid) portion of the tears responsible for protecting the aqueous portion from evaporation. Lastly, there is a mucous portion, found attached to the cornea and conjunctiva that helps in spreading the tears for lubrication.

Frontal view of a healthy cornea.

Filamentary keratitis refers to a common, advanced state, of dry eye whereby strands of epithelium, the outermost layer of the cornea, mucous, and cell debris form on the cornea. These strands tend to be strongly attached to the cornea. With each blink, the strands are pulled in one direction or another and cause considerable discomfort.

Frontal view of a cornea with filaments.

Signs and Symptoms

Signs

Red eyes, stringy discharge, low tear volume, filaments attached to the cornea.

Symptoms

Foreign body sensation, sometimes light sensitivity, dry eyes.

Causes and Risk Factors

Causes

Extreme dry eye from exposure of the eye, low tear volume, poor tear composition.

Risk Factors

Lagophthalmos (eyelids never shutting completely), autoimmune conditions (Rheumatoid arthritis, Sjogren’s, etc.), medications causing dry eyes, excessive contact lens use, cataract surgery, laser eye surgery, causes of neurotrophic keratitis.

Prevention and Treatment

Prevention

Supplement your tears with artificial tears if you are taking a medication or have an eye condition listed above. Maintain proper lid hygiene, maintain a diet rich in omega 3s, avoid smoking, avoid dehydration, take 20 second breaks every 20 minutes to blink when reading or on the computer.

Treatments (depending on the cause)

· Preservative free artificial tears.

· Alter medications.

· Remove filaments one by one.

· Hypertonic (salt) eye drops.

· Bandage contact lens to help with the pain.

· Mucolytic agents to break up the mucous strands.

· Cyclosporin drops for pain.

· Steroid drops to decrease inflammation.

· Punctal plugs to allow tears to stay on the eyes longer.

Prognosis

Filamentary keratitis, in most cases, is very manageable. With that being said, depending on the cause, there may be no cure. In most cases, filamentary keratitis will be only a minor inconvenience of comfort but in severe cases, can cause a lifetime of extreme discomfort, vision fluctuations, and ocular surface diseases.