strategic skill builders
Keeping the Eye Quiet
See how to best determine the cause of a contact lens wearer's symptoms and how to manage them.
BY JEFFREY C. KROHN, O.D., F.A.A.O.
In this modern era of disposable lenses, successful contact lens wear poses fewer threats than it used to. The world we live in, however, still presents a challenge and significant threats remain in the areas of toxic responses and allergic responses of the eye to airborne substances. It's important to correctly assess the cause of a patient's symptoms. I'll walk you through what I think is the best way to make this determination.
INTERVIEW YOUR PATIENTS
Patients who present with a response to an environmental substance typically offer up certain
symptomatology. While itching is the most likely reported symptom of a patient who has allergic tendencies, you shouldn't ignore other symptoms of ocular surface irritation. However, the "triad of redness, itching and foreign body sensation" is highly suspicious of an allergic condition.
If a patient reports a positive ocular irritation, then determine whether the symptom is unilateral or bilateral, if it's constant or intermittent, if it occurs with or without contact lens wear and whether it follows any other pattern. Document the presence of other associated symptoms such as puffiness, watering, redness or discharge and explore the details of these symptoms.
Because we're concerned about keeping the eye quiet, the wise clinician will know plenty about the contact lens wearing experience. Ask patients who wear rigid lenses about the frequency of lens "polishing" and replacement. Ask hydrogel lens wearers about the frequency of lens replacement and the average "life span" of a pair of lenses. Both types of wearers would benefit from discussing their lens care and wearing patterns with you. Compliance patterns of each individual vary and the time spent discovering each patient's pattern of noncompliance is time well spent. It's wise to document the average length of time each patient leaves his lenses on his eyes, the average number of days each week (or month) he wears the lenses, whether he wears them overnight at all and exactly how he takes care (or doesn't take care) of the lenses.
You should also explore the environment in which a patient spends his time. Those who smoke, or are exposed to second-hand smoke, may experience reduced contact lens success. A practitioner might misdiagnose those who live or work in an unfriendly environment with an allergic condition when the problem is actually toxic. Other lifestyle factors that contribute to dryness of the ocular surface will certainly contribute to the problems of a contact lens wearer who has a predisposition to allergies.
TAKE A CLOSER LOOK
Examination of the skin may reveal signs of eczema or dryness. For example, the nose may reveal rosacea or the scales of seborrhea. Scales and flakes of the scalp and hair are also more prevalent in someone who has an atopic profile.
Erythema to the outer surface of the upper lids is a sign of contact dermatitis from airborne particles. Redness to the exterior of the lower lids can indicate dermatitis from substances put on the eye such as eye drops (prescription or over the counter), cosmetics or lens solutions.
The allergic shiner -- a darkening to the skin in the lower lid region -- "is a common sign in the atopic patient." A slightly invasive screening test involves scratching the skin with the fingernail. Unlike the normal patient, who responds with a delayed erythema to the skin, the atopic individual may respond with whitening to the skin of the area scratched. This "white
dermato-graphism" occurs because of a greater-than-average edematous response that obscures the capillary dilation. Itching of the eyelids rather than the eye might not be related to a true allergic response. You should rule out lice among the eyelids, meibomian gland stagnation/infection, blepharitis and dermatitis.
RULE OUT SIMILAR CONDITIONS
When history suggests a possible allergic condition, conduct a complete dry eye work up as a first step because ocular surface disease and dry eye syndrome are often confused with an allergic response. Evaluation of the lids, tear film quantity and quality and fluorescein staining are an absolute bare minimum. I can't stress enough the importance of evaluating the lids, as you can provide relief to the majority of patients who experience contact lens wearing discomfort with lid hygiene and/or therapy. Lash debris, erythema and induration of the eyelid margins and the quality and quantity of the meibomian gland expression are important pieces of the puzzle that you should gather for each patient. Examination of the external canthus should rule out the possibility of angular
blepharoconjunctivitis. Because Moraxella feeds on dead epithelial cells, blepharoconjunctivitis is more prominent in dry eye and ocular surface disease than it is in allergic conditions.
REDUCE POSSIBLE CULPRITS
The bulbar conjunctiva typically shows pink, diffuse erythema in response to an allergic response. Again, the edematous response may be excessive and thus obscure the true redness. Patients may also self treat themselves with vasoconstrictors, leading them to look better than they feel. Careful optic-section evaluation of the bulbar conjunctiva should reveal chemosis in a true allergic response.
Unlike infectious conjunctivitis, the conjunctival response is often greater in the exposed interpalpebral area, rather than in the organism-preferred
fornix. Typically you'll see little staining of the bulbar conjunctiva in an allergic response. Edema, however, is often easier to detect with fluorescein and a barrier filter, which eliminates background "noise" reflecting off of the sclera.
Evaluation of the palpebral conjunctiva will further reduce the number of possible conditions responsible for the patient's symptoms. Because of the tight connection of the upper palpebral conjunctiva with the tarsal plate, an erythema without any obscuring edema (papillae) is present in any inflammatory response. The unique, large (>3mm) and flattened cobblestone papillae typical of vernal keratoconjunctivitis
(VKC) are well described as is its proper management. Also large, the papillae from giant papillary conjunctivitis (GPC) have a more parabolic shape, typically showing white degenerative apices. Although there is some confusion over the exact mechanism in GPC, a mechanical rather than allergic etiology is finding increased support.
Because the inferior palpebral conjunctiva has plenty of lymphatic channels and is loose and spacious enough for a pronounced edematous response, it will respond differently than the superior tissue. As described previously in "white
dermatographism," the edema and collection in the lymphatic channels of the inferior palpebral conjunctiva (follicles) obscures the
erythema. Evaluation of the palpebral conjunctiva with the cobalt blue and barrier filter combination will not only elicit areas of damaged cells, but will also facilitate papillae appreciation and allow detection of small strands of mucus.
Allergic conditions rarely affect the cornea so any punctate epithelial keratitis
(PEK) should put you on guard. If PEK is present, ocular surface disease, medicamentosa or Staphylococcal exotoxin hypersensitivity is a more likely diagnosis (or is concurrent). The appearance of Trantas Dots in the limbal region indicate a VKC response and a corneal "shield" ulcer is possible. Also, the presence of subepithelial infiltrates should point you to another etiology. Because anterior basement membrane dystrophy could present with similar symptoms, it's important to carefully evaluate this corneal layer to rule it out.
KEEPING THE EYE QUIET
You should maintain a primary goal of achieving a well-hydrated eye and contact lens surface. Here are some tips for getting inflamed, allergic eyes under control:
Lubrication provides enhanced removal of ocular irritants from the surface of the lens. Without lens wear, the tears provide a defense against the allergic inflammatory cascade. Unfortunately, contact lenses disrupt the tear film characteristics and also replace the cornea as the most anterior "non-tear" surface. As lenses age, the formation of true surface deposits decrease the hydrophilic properties of the material and lead to increased dryness. Even in the case of daily disposable lenses, pellicle immediately forms on the lens surface.
Although using lubrication during lens wear can prove cumbersome and may seem impractical for some patients, you should always consider it early on in your therapy decision. The use of punctal occlusion is a bit more problematic (see "What About Punctal Plugs? pg. 66).
In the past, conventional wisdom pointed to the use of preserved artificial tears when dosage was
q.i.d. or less, switching to unpreserved compounds if dosage was more frequent. With the introduction of "softer" preservatives, this approach is less critical. Some of these products haven't been tested or approved for use concurrently with contact lenses and you should inform patients of this fact. As in the past, avoid the use of products that contain benzalkonium chloride because it has been shown to cause epithelial erosion to the cornea with repetitive use.
|WHAT ABOUT PUNCTAL PLUGS?
At the University of California School of Optometry's 75th Anniversary Program (a.k.a.
BobFest), Dr. Gerald Lowther reported some interesting findings related to punctal occlusion.
When researchers inserted a collagen plug in only one punctum and convinced the patient that the procedure was bilateral, symptoms reduced in both eyes.
Patients who have bilateral silicone plugs showed a marked improvement in symptoms one week later. After five weeks, the improvement was barely improved from baseline.
Patients without dry eye syndrome were plugged. Epiphora occurred immediately, however it was decreased four to five days later and disappeared after one week.
These observations have led to the hypothesis that there is a "feedback" mechanism present that keeps the production of tears at a certain level. Occluding the puncta may temporarily increase the tear volume, only to be followed by a decrease in production so that the tear volume returns to it's "pre-plugged" level. How pervasive this response is and whether it occurs to a different extent in normals compared to true aqueous deficient patients has yet to be shown.
Also, the "cesspool" affect, which Drs. Lou Catania and Art Epstein discuss, is worth considering. Punctal plugs do retain the components of the tears on the surface of the eye longer and in cases of true dryness without inflammation, this is helpful. Also, when compounds are added to the eye that require long contact time, occlusion is beneficial. However, in true inflammatory conditions, you should encourage the elimination of those compounds in the tears, which might prolong the irritation. Avoid punctal occlusion in true allergic reactions in deference to true treatment of the condition.
Lid hygiene. As well as enhancing the balance and quality of the tear film, lid hygiene will remove irritants and waste products present in the "collecting region" (i.e., the lacrimal lake) of the eye. In my opinion, all contact lens patients would enjoy increased comfort, clarity and ocular health if they practiced eyelid hygiene.
Using mast cell stabilizers. Theoretically, for patients who report symptoms extremely suggestive of allergic conjunctivitis, you should treat them with mast cell stabilizers before objective signs appear. Realistically, these patients don't present in our office until the eye is already responding.
Because most mast cell stabilizers were developed to treat active conditions (e.g., vernal conjunctivitis), they're not approved for use during contact lens wear. Also, many were developed as oral or nasal medications and not primarily as topical formulations. There is also controversy about what type of mast cells truly respond in ocular allergies and what type of medications have truly been shown to stabilize mast cells present in the human conjunctiva.
It's possible that some mast cell stabilizers are effective because of their activity as an ocular lubricant rather than as a true therapy. Also, if you prescribe the medications at a
q.i.d. dosage, then there's the potential of an iatrogenic irritation from preservative absorption into the lenses
(BAK is used in almost all mast cell stabilizers). Consider b.i.d. dosage (one drop before inserting the lenses and a second drop after removing the lenses). Two agents are designated on their package insert as both an antihistamine and mast cell stabilizer
(olopatadine [Patanol] and ketotifen [Zaditor]). The use of these agents on a before-and-after contact lens wear basis is becoming a popular prescribing strategy.
Discontinue lens wear. As well as removing a "landing site" for allergens, deprivation acts as a provocative test for other potential causes (solution intolerance, corneal exhaustion, etc.). In cases where total deprivation is impractical or unlikely, use a trial course of daily disposable lenses for most patients.
Use cold compresses.
Application of a cold pack to the closed eyelids has been a treatment mainstay of ocular irritation from allergies for years and can bring relief to even the most severe presentations. The use of crushed ice, fluid-filled masks and even frozen vegetables have been suggested to create a good cold compress.
Prescribe antihistamines. Ophthalmic preparations such as levocabastine
(Livostin), emastadine (Emadine) and azelastine (Optivar) have indications for the relief of itching as a topical antihistamine. Use of these preparations gives you a choice in minimizing this main symptom of allergies. However, all of these agents contain BAK as their preservative -- which makes it problematic for contact lens wearers to use them during wear. Hence we need to weigh the benefits and risks of each component of a prescription for patients who wear contact lenses.
IMPROVE THE ENVIRONMENT
Many toxic and allergic reactions stem from the environments in which a patient spends the majority of his time. Therefore it's important to eliminate allergens, reduce toxins and improve humidity.
Allergic reactions are best handled by eliminating the offending particulate. Relocation to an arctic climate may reduce the signs and symptoms of allergic eye disease, but most patients wouldn't seriously consider such a move. Instead, encourage patients to think about patterns associated with symptom occurrence, both in respect to timing and location. Articles of clothing, cosmetics, soaps, animals and latex are just a few of the potential offenders. Patients who awake with allergic conjunctival symptoms may consider a change in the type of pillow they use. In stubborn cases, advise the patient to consult with an allergist.
Poor circulation, improper humidity and crowding factors, which combine to form "sick building syndrome," may affect a patient's environment. Backman and Haghighat studied ocular irritation and sick building syndrome and found that dry eyes and ocular discomfort (both common symptoms in allergies) showed good correlation to the syndrome. Air travel within the office, along with the use of video display terminals has been suggested as contributing to contact lens intolerance. It's prudent to encourage fresh air circulation, fewer individuals per room and evaluation of building ventilation systems.
Improve humidity. Environ-mental humidity has been shown to increase the thickness of the tear lipid layer. Along with the other changes that contact lenses cause to the dynamic of the ocular surface, remember that patients who give up their spectacles are also giving up a "windbreak" and a minor humidification chamber. You can suggest traditional humidification techniques when appropriate.
While we'll never eliminate the possibility of the reaction of the ocular tissue to irritants and allergens, we need to be ready and able to assist our patients in quieting down the uncomfortable signs and symptoms of allergic eye disease. We should also strive to identify those patients who might be likely "responders" and treat them before the fact to prevent a reaction and keep their eye quiet.
Dr. Krohn is a partner in a group practice in Fresno, Calif. He's also a fellow of the American Academy of Optometry and is a diplomate of the Academy's Section on Cornea and Contact Lenses. Dr. Krohn has also lectured and published on numerous topics.
Optometric Management, Issue: April 2003