Article Date: 8/1/2005

LENS DRYNESS
Use Your Ears to Identify Lens Related Dryness
Help retain contact lens wearers by "listening" to their symptoms.
By Robin L. Chalmers, OD, and Carolyn G. Begley, OD, MS

Dryness and discomfort with contact lenses affect nearly half of all soft lens wearers. The large number of dry eye sufferers wearing soft lenses, estimated at 16 million in the United States alone, should be strong motivation for eyecare practitioners to re-examine their approach to diagnosing and treating the problems of their symptomatic contact lens patients.

Symptomatic lens patients not only have a negative experience, but are at higher risk of limiting their wearing time and abandoning lens wear altogether. Reports show that most patients who discontinue contact lens wear are in their mid-20s when they begin lens wear and stop within the first two years of wear. You lose your chair-time investment with a patient who soon discontinues lens wear because you've ignored or glossed over his comfort problems.

Through the past decade we've researched the measurement of ocular surface symptoms and developed methods to elicit them in dry eye patients and contact lens wearers alike. Our research has re

shaped our thinking on how eyecare practitioners should approach mild to moderate dry eye and contact lens-related dryness. Here we'll outline findings that support reasons to better diagnose contact lens-related dryness and that point to effective treatment strategies.

Why Bother with Lens Dryness?

In 1998, with the help of a collaborative research team, we studied more than 1,000 unselected clinical patients presenting for eye care in six clinical centers in North America. We also distributed the newly developed Dry Eye Questionnaire and Contact Lens Dry Eye Questionnaires (DEQ and CLDEQ) to patients presenting for all types of eye care to establish population norms for ocular surface symptoms.

Surveying patients who are not selected for their dry eye diagnosis is the best method to determine the breadth and seriousness of the problem of ocular dryness in the population overall, as well as to establish normal symptoms reported by patients who don't suffer from dry eyes. It's possible to compare these symptom norms to symptoms among groups of patients who have various types of dry eye to see if their symptoms alone distinguish them from patients who don't have dry eye diagnoses. Although they're not a group who have a dry eye diagnosis per se, we studied contact lens wearers as a distinct group to compare to non-lens wearers.

The DEQ and CLDEQ questionnaires thoroughly query a number of habitual ocular surface symptoms, contact lens wearing history and habits, along with other lifestyle factors that may influence dryness symptoms. First, we establish the frequency of each symptom. If patients report that symptom, then we gather the intensity at the beginning and end of the day. At the end of the survey, we ask patients whether they had a practitioner- or a self-diagnosis of dry eye as a global indicator of their condition. Research shows that practitioners often underestimate patients' perception of their dry eye condition in both contact lens wearers and non-wearers alike. Nearly 40 percent more contact lens wearers described themselves as having dry eye (17.7 percent) compared to those told that they had dry eye by their practitioner. Patients who self-diagnose but aren't given a practitioner diagnosis represent patients whose needs are not being met by their eyecare providers.

Among the 1,054 subjects we surveyed were 367 current contact lens wearers and 181 former lens wearers (26 percent of those who weren't currently wearing lenses). The former lens wearers cited dryness and late-day discomfort as their top two reasons for discontinuing lens wear. As shown in Table 1, four of the top five reasons relate to ocular surface sensations rather than inconvenience, cost or other reasons unrelated to lens comfort. These results agree with researchers from the University of Waterloo who found that 50 percent of patients cited discomfort or dryness as the rea

son for discontinuation. They also reported that patients who discontinued lens wear had a reduced wearing time compared to successful wearers. A more recent UK study concurred, finding that 51 percent of the subjects cited discomfort as the principal reason for giving up contact lens wear.

How Patients Cope with Symptoms

Our study of unselected patients showed that compared to non-wearers, the contact lens wearers reported significantly more frequent and intense symptoms, particularly discomfort and late-day dryness. In another section of the questionnaire, we asked about symptoms when contact lens wearers weren't wearing their lenses and found that lens removal greatly relieved these patients' symptoms: no surprise to the clinicians on the team. Frequent to constant dryness was reported by 26.8 percent of subjects while wearing lenses and only 6.2 percent without their lenses in place. Fifty-five percent of the contact lens wearers also reported symptoms that were triggered by environmental factors of smoke, smog, air conditioning or central heating, much higher than among the non-wearers. Contact lens wearers avoid these environments if their lenses exacerbate their dryness.

Thus, the clinical picture for lens-related dryness comprises a majority of patients whose eyes are fairly free of symptoms without lenses but become quite symptomatic during contact lens wear. Typical contact lens wearers manage their dryness symptoms primarily by removing their lenses (55.8 percent), using contact lens rewetting drops (47.1 percent) or artificial tears (14.8 percent). Patients who reported that they remove lenses cited dryness as the most common reason. Removing lenses did relieve symptoms; 47.4 percent of patients who practiced this coping strategy reported it was completely effective. Alternatively, rewetting drops were rated as giving complete relief by 22.3 percent and artificial tears by only 4.7 percent of those who used them. There is definitely room to improve the effectiveness of treatment for contact lens-related dryness.

How can we predict or avoid contact lens-related dryness in our contact lens patients? First we must understand the varied factors that can influence or cause sensations of dryness on the ocular surface, with or without contact lenses.

TABLE 1 - Top Five Reasons for Lens Dropouts

REASON  % IMPORTANT/ VERY IMPORTANT
Eyes felt dry 42.5%
Late-day discomfort  40.3%
Lenses felt scratchy/irritating 37.6%
Wearing lenses too much trouble 35.9%
Lenses uncomfortable all day    30.4%

Factors that Influence Dryness

Contact lens wearers in the new millennium lead lives that include many work or lifestyle factors that may negatively impact contact lens comfort. As a group, contact lens wearers are growing older, wear lenses for long wearing days, may live or work in challenging arid environments and use more over-the-counter (OTC) medications with drying side effects than in previous decades. Most likely they commute longer distances to work, drink more coffee and other caffeinated beverages, fly more frequently and spend many more hours in front of computer screens than did patients in the 1980s and 1990s. All these factors may drive dryness sensations in contact lens wearers. As outdoor air becomes more polluted, indoor air quality deteriorates even though it's more highly conditioned. Patients' eyes are bombarded with factors that may make their ocular surface less than ideal for contact lens wear.

Table 2 shows the self-reported use of medications with drying side effects among contact lens wearers from our 1998 study. Since that time, a number of widely used drugs have come on the prescription or OTC market, including loratadine (Claritin) for the self-prescribed treatment of allergies. OTC antihistamines and similar compounds have drying effects on the ocular surface, causing increased symptoms. These drugs used by millions of patients represented a global market of more than $3.3 billion in 2001, according to IMS Health's World Review. Often a full-time wearer has no choice but to seasonally use oral antihistamines even though they may exacerbate dryness symptoms. The use of anti-depression medications is also on the rise among adults. The IMS Health's World Review states that anti-depression medications account for the third largest class of medications sold, amounting to $13.4 billion, with a growth of 18 percent over the previous year. In addition, older contact lens wearers, many of whom are now well past their 40s but dedicated to contact lens wear, are more likely to use a plethora of pharmaceutical agents to treat conditions related to advancing age.

The amount of time contact lens patients spend using computer screens has also increased dramatically over the past few years. Staring at computer screens reduces the blink rate, resulting in surface drying of lenses and the discomfort sequelae that follow. In our study of unselected patients, we found that 26.4 percent of contact lens wearers used a computer for more than six hours each day while at work, in addition to their recreational computer use. The penetration of home computers, mobile personal data devices and cell phones with input or text screens has grown exponentially in the past few years in the US market. For example, the proportion of US households with a home computer rose from 52 percent to 62 percent from 2002 to 2003, according to Nielsen/NetRatings. Time spent on recreational computer use likely rose proportionally.

The Practitioner's Best Strategy

Because of changes in these lifestyle factors that may reduce a patient's chance of success with contact lenses, we propose that practitioners begin a more active, probing discussion about ocular surface symptoms as part of their routine case history for new and current contact lens wearers.

To illustrate how to conduct a more problem-oriented, revealing case history, let's examine an analogous problem in vision care: presbyopia. If a 40-year-old emmetropic patient presents for examination without any vision complaints, how many eyecare practitioners would miss the opportunity to counsel the patient on the impending change in his near vision? Very few of us would. Because practitioners are well-equipped with both knowledge of the process of presbyopia and tools with which to treat it (even if no treatment is required at the moment), practitioners will usually discuss the condition because patients will benefit from knowing what's about to happen to their vision. The patient's knowledge will reduce worry and stimulate him to seek treatment when his declining near vision becomes bothersome.

Similarly, if practitioners familiarize themselves with knowledge about contact lens-related dryness and are familiar with effective options with which to treat those contact lens wearers (more lubricious lens materials, non-toxic care systems, tear replacements) then they'll likely be more willing to initiate a guided discussion about dryness symptoms with their contact lens patients.

Nowadays soft lens materials on or coming to the market have physical properties that relieve or reduce symptoms of dryness in many contact lens wearers. Practitioners can now treat symptoms that may have posed a stubborn, intransient problem in the past, reinforcing the value of routine eye care to the patient. Now is the time for practitioners to revamp their diagnostic skills with regard to contact lens-related dryness.

TABLE 2 - Self-Reported Medication Use

MEDICATION % OF CL WEARERS
Oral antihistamine 35.6%
Oral contraceptives 15.2% (of females)
Depression medication 6.4%
Thyroid medication 3.9%

 

Listening for Symptoms

Paradoxically, contact lens wearers who report frequent or intense symptoms of dryness don't look like patients who have pathological dry eye. Often they don't even have a rapidly drying lens surface between blinks as measured by non-invasive tear break-up times. A thorough, routine contact lens examination will reveal that most symptomatic contact lens patients have an adequate supply of tears, no frank inflammation and don't exhibit significant signs of ocular surface damage that would be present in even moderate dry eye patients who don't wear lenses. Standard clinical tests to diagnose pathological dry eye such as the Schirmer test, tear prism height and degree of corneal fluorescein staining don't correlate well with symptoms in dry eye sufferers. Because contact lens-related dryness is a problem with few clinical signs, the clinician must query and listen for, rather than look for, contact lens-associated dryness among their existing contact lens wearers. When clinical signs are within normal limits, symptoms that exceed the norm must be considered the "sign" of contact lens-related dryness.

Researchers who have studied the most-often-used "tests" for diagnosing dry eye found that the case history was most often used by experts in the dry eye field and by practitioners in a variety of health care settings. The case history to elicit symptoms, however, wasn't standardized or easily quantified as to whether the symptoms were normal or abnormal, complicating the diagnostic effort. We propose using a short series of questions to open the discussion about contact lens-related dryness. The answers will help determine whether patients could benefit from a treatment plan directed at reducing dryness symptoms.

Our sample questions include querying the typical number of hours of comfortable lens wear compared to the number of hours patients actually wear lenses each day. A disagreement of more than two hours (total hours worn minus comfortable hours worn) indicates a patient who is struggling to wear lenses toward the end of the wearing day. We also suggest probing on late-day symptom intensity because patients who globally described themselves as having dry eyes often reported these symptoms, even though their practitioners didn't diagnose them as having dry eyes.

Fine-Tuning Your Thinking

Many symptomatic contact lens patients present for eye care with eyes that appear normal but are causing symptoms of discomfort and dryness, especially late in the day. You can treat these patients with lenses designed to reduce dryness symptoms and careful choices of lens care. With new thinking and simple questions, you can begin to tune your contact lens exams and product recommendations and use all the tools available to help your patients who have contact len-related dryness symptoms.

Patients will certainly notice the extra care and are likely to remain in lens wear for much longer.

For references, visit www.clspectrum.com/references.asp and click on document #117.

Dr. Chalmers is an Adjunct Professor at Indiana University School of Optometry and an independent Clinical Trial Consultant. A University of California School of Optometry graduate with 20 years in contact lens research, she has worked for the past decade primarily on contact lens complications and measurement of ocular surface symptoms.

Dr. Begley is an associate professor at the Indiana University School of Optometry and is also a member of the Graduate Faculty.

 


Contact Lens Spectrum, Issue: August 2005