Conjunctivitis

Conjunctivitis (inflammation of the conjunctiva) is a very common disease that causes inflammation and swelling in the tissues that line the inner lids and front of the eye. This condition is often seen in contact lens wearers, but can also be found in patients who suffer from allergies and bacterial or viral infections. Conjuctivitis can take on a variety of different forms, depending on the severity of symptoms. The example above illustrates a form of conjunctivitis called Giant Papillary Conjunctivits.

Signs and Symptoms

The most common sign of conjunctivitis is a surface disruption of the inner eyelids. On lid eversion, the conjunctival tissue will appear injected (blood vessel dilation) and inflammed. In more advanced cases, the inner lid will have a cobblestone appearance. This cobblestone effect is the result of papillary formations (inflammed tissue and swollen vessels that give rise to "bumps") that have developed in response to antigens. Other symptoms may include...

· Hyperemia of the conjunctival blood vessels (vessel engorgement)
· Corneal epithelium disruption
· Excessive tearing, purulent discharge, redness, itching, and foreign-body sensation
· Photophobia (light-sensitivity)
· Contact lens intolerance, with blurred vision after insertion

Photo of
Severe Papillary Conjunctivitis

In soft lens wearers, conjunctivits may develop as soon as three weeks, or take as long as four years to manifest. In rigid lens wearers, it typically appears after 14 months.

Causes

A critical issue in formulating strategies to treat or prevent conjunctivitis is to determine the specific causative antigens involved in each particular case.

Contact Lenses

Protein deposition on the surface of a contact lens is the most common precursor for developing conjunctivitis. However, protein on lenses of patients with conjunctivitis is indistinguishable from protein on lenses of patients without conjunctivitis. The antigenic stimulus could also be one of a number of other potential lens contaminants, such as lipids, calcium and mucus. Microorganisms such as bacteria (and bacterial endotoxins) may also trigger the problem.

The type of plastic used to fabricate the contact lens may have an antigenic role. In order to reduce the incidence of contact lens induced conjunctivitis, many manufacturers now provide lens materials that are more resistant to protein, lipid, and calcium build-up collected from the tear film.

Early generation preservatives such as thimerosal and benzalkonium chloride are known to have a causative role in the development of conjunctivitis. For sensitive eyes, it is recommended that preservative-free lens care systems be used.

Mechanical trauma

Papillary conjunctivitis of an apparently identical form to that induced by contact lenses has been observed in patients who do not wear contact lenses but whose tarsal conjunctivae have been exposed to various types of mechanical trauma, such as:

· Plastic ocular prostheses
· Extruded scleral buckle (following retinal detachment repair)
· Excessive cyanoacrylate glue used to close a perforated cornea
· Protruding nylon sutures (following corneal or lid surgery)
· Rigid contact lens embedded in upper fornix
· Elevated corneal deposits
· Epithelialised corneal foreign body (membranous growth over embedded foreign body)

Allergies

People can develop seasonal, perennial and food allergies at any age. Allergic reactions are triggered by the body's immune system to protect the eyes from injury. The immune system mistakes usually harmless substances (such as pollens) for harmful foreign intruders (such as bacteria) and over-reacts, producing allergy symptoms ranging from mild to severe. The result can be considerable discomfort, tissue damage and sometimes impaired vision. To read more on how the body responds to allergens,

Treatment

Treatment options fall into four categories:

Contact lens alterations

All soft lenses develop deposits over time. Most of these deposits can be removed by daily surfactant cleaning, but some deposits such as protein gradually build up regardless. Protein removal systems may slow the rate of protein build-up but they do not prevent it. If protein accumulation on the lens surface is determined to be the cause, effective lens-related strategies include...

· Changing to a lens material that resists protein build-up
· Changing to a lens material that deposits less protein
· Changing to a rigid lens or biocompatible material
· Replacing lenses more frequently

Cessation of lens wear will usually result in an effective cure, but such an option is generally met with little enthusiasm by patients. In more severe cases (grade 3 or 4), ceasing lens wear for a brief period of one week will enhance the prospect of success of subsequent treatment. Similarly, a reduction in wearing time in the early phase of treatment will optimize the prospect for recovery.

A rigorous approach to protein removal may alleviate contact lens induced conjunctivitis. The introduction of protein removal systems into the regimen of those patients that do not use them, or an increase in frequency of usage (e.g. from weekly to bi-weekly or even daily) may be beneficial. This applies to both soft and rigid lens wearers.

If preservatives in contact lens solutions are thought to be of actiological significance in a particular patient, then the employment of preservative-free systems (some hydrogen peroxide solutions fall into this category) may alleviate the condition.

Improving ocular hygiene

Improvements to ocular hygiene begin with improvements to personal hygiene. Thus, routine thorough hand washing prior to lens handling and regular face washing should mitigate against developing conjunctivitis. Twice per day warm compresses, followed by lid scrubs will help to remove and express lid margin debris and bacteria.

Minimizing exposure

A first step in treating eye allergies is to minimize exposure to known irritants. Here are a few things that you can do inside your home....

· Air filtering
· Humidity regulation (to reduce mold and mildew)
· Avoid perfumes, harsh detergents, and carpet deodorizes

Pharmaceutical agents

A variety of medications have been advocated for the treatment of conjunctivitis and the provision of symptomatic relief. Agents that act by stabilizing mast cell membranes, thus preventing the release of inflammatory mediators such as histamine, are helpful in the treatment of allergic conjunctivitis.

In severe cases of conjunctivitis, topical steroids aid in the reduction of papillary hypertrophy and injection associated with the condition. Unfortunately, long term therapy with most topical steroids is contraindicated due to potential side effects such as increased IOP and posterior sub-capsular cataract formation.

Sources

* Portions of text obtained from the Manual of Ocular Diagnosis and Therapy. Pavan-Langston, M.D., Little, Brown and Company, 1991.