Q: A patient who has persistent filamentary keratitis following a severe head trauma has responded well to a bandage contact lens, but I dont want him to have to rely on a bandage lens forever. What are the alternatives?
A: To determine alternative treatments, first ascertain the underlying cause of the filamentary keratitis, says optometrist Arthur B. Epstein, of Rosyln, N.Y. Causes include superior limbic keratoconjunctivitis (SLK), recurrent corneal erosion, epitheliopathy due to aerosol or radiation keratitis, prolonged patching following cataract or other ocular surgery, bullous keratopathy, herpetic keratitis (both simplex and zoster), neurotrophic keratitis and systemic disorders such as diabetes and psoriasis.1
The head trauma leads me to believe that this patient has a neurotrophic cornea as a result of damage to the sensory corneal nerves, Dr. Epstein says. And, this damage has led to dry eye, which has caused the filamentary keratitis.
Another theory: Because of the head trauma, this patient is possibly in a vegetative state, which may have decreased his blink rate, causing dry eye, says optometrist Andrew S. Gurwood, of the Pennsylvania College of Optometry, in Elkins Park, Pa.
If dry eye is the cause, there are at least five alternative treatments to a bandage contact lens, namely:
Frequent use of artificial tears. These balance the tear films oil, water and mucin, precluding the mucin from locking onto the lid and pulling the epithelium off in strips, Dr. Gurwood says.
Dr. Epstein recommends Bion Tears (Alcon) or TheraTears (Advanced Vision Research) for use eight times a day. Both have no preservatives and are generally well tolerated. Patients can use other artificial tears as well, he says. He also suggests that patients use Systane (Alcon) as an initial and primary therapy because it helps resurface the cornea and may minimize the formation of filaments.
|Filamentary keratitis has several causes, including dry eye.|
The agent is effective, but there are three issues with it, Dr. Gurwood adds. It generally has to be formulated by a pharmacist, it generally has a foul smell, and the preservative causes it to turn pink after a couple of days, making patients think it is no longer safe to use.
Patients should apply the spray four times a day, he says.
Sodium chloride 5% ointment. Sodium chloride ointment or solution is a hypertonic preparation that uses the principle of osmosis to dehydrate the cornea, Dr. Gurwood says. It can reduce corneal edema, promote better healing by providing an environment that promotes proper interlocking of tissues in the cornea and can also augment the aqueous layer of the tear film.
Prescribe for use in the morning and at bedtime, he says.
Physical removal of the filaments. Instill a drop of anesthetic into the eye, and use jewelers forceps or a cotton-tipped applicator to remove the filaments. These come off as strands, Dr. Gurwood says.
One caveat: The issue with filamentary keratopathy is always the underlying cause, he says. Therefore, removing the filaments may arrest the acute discomfort, but its not the solution to the problem.
Botulinum injections to the orbicularis muscle. Prescribe this treatment for patients who have head trauma and do not respond to treatments, such as those mentioned above. I have had patients who underwent this procedure, and the keratitis did not recur, even after the effects of the toxin had worn off, says Oliver D. Schein, M.D., of Johns Hopkins University, in Baltimore. This response suggests that an abnormality in the interface between the lid or tarsus and the cornea may be the key here.
1. Sowka, JW, Gurwood AS, Kabat AG. Filamentary keratitis. In: Review of Optometry Handbook of Ocular Disease Management. 2002 Oct;139(Suppl):21A.