Navigating the "Vale of Tears"

Clinicians verify that a one-drop-fits-all approach won't work for dry eye.

BY RENÉ LUTHE, SENIOR ASSOCIATE EDITOR

With so many dry eye drops currently on the U.S. market, it seems that there must be an ideal drop out there for every variety of dry eye sufferer. While that may be true, it leaves the physician with the task of shepherding patients through the process of choosing and using artificial tears to find a solution that works best for each individual. Below, several dry eye specialists explain what factors they weigh in finding their patient's perfect (dry eye) match.

A Real Problem

Dry eye is a disease that physicians still underestimate — both in its prevalence and in its impact on patients' quality of life, according to Joseph F. Mussolini, M.D., a clinical instructor and assistant surgeon at Philadelphia's Wills Eye Hospital and surgical director of the Campus Eye Ambulatory Surgery Center in Hamilton, N.J.

"When I give lectures and tell doctors that dry eye really affects the patient's quality of life, they look at me like, ‘You're kidding me,’" he says. "But a study from 2003 found that patients rated dry eye's impact on their quality of life as comparable to that of cardiac angina.¹ That's a huge statement! Cardiac angina gets people running to the ER. But they thought dry eye affected their lives as much."

Penny Asbell, M.D., professor of ophthalmology at Mount Sinai School of Medicine and Director, Cornea Services and Refractive Surgery Center in New York City, agrees that doctors typically grossly underestimate the impact of dry eye on patients' lives. "I like to explain it to my peers as a little bit like back pain," she explains. "We don't see when someone has back pain — they usually look normal, but they are unhappy. And any of us who have ever had back pain, or had friends or family who have had it, know how much chronic pain can interfere with the daily activities and quality of life. And that's what dry eye disease is: a form of chronic pain."

It's All in the Diagnosis

To diagnose dry eye, according to Dr. Mussolini, the physician must actively look for it rather than rely on patients to initiate the discussion. He says that patients have often become so accustomed to a degree of irritation and redness that they no longer consider it a real problem. Upon entering the examination room, he asks each patient how his or her eyes feel, regardless of their stated reason for the visit.

"They look at me rather confused, and I ask, ‘Are your eyes itchy, do they have a foreign-body sensation?’ Listen to the response to the question. They may be at the practice for something as simple as a refraction but might answer, ‘You know, my eyes have been really scratchy. They have this gritty feeling.’"

Then comes the more formal diagnostics. Dr. Mussolini first checks tear film break-up time. "If it's breaking up below the 7-second threshold, you know they have some dryness on the ocular surface," he says.

Calvin W. Roberts, M.D., clinical professor of ophthalmology at Weill Medical College of Cornell University in New York, prefers lissamine green staining over Schirmer strips. "Some people like to do Schirmer's, although I haven't found it all that helpful," he says. "But I love the lissamine green, love looking at the staining pattern. That's really going to tell me where the cause of the problem is."

Karl Stonecipher, M.D., director of Laser and Refractive Surgery at the Laser Center in Greensboro, N.C., notes that some severe dry eye patients may have prominent signs but few symptoms. "They will have very prominent lissamine staining, and the cornea ‘lights up’ with fluorescein." But if they've undergone cataract or refractive surgery that affects the architecture of the nerve plexus, "these patients may not pick up on the dry eye."

The most significant factor in choosing a dry eye drop for a patient is determining the cause, according to Dr. Roberts.

James McCulley, M.D., professor and chairman of the Department of Ophthalmology at the University of Texas Southwestern Medical School in Dallas, agrees with that approach. "If it's a primary, underlying inflammatory disease like Sjögren's, I will initially treat the inflammatory process," he says. "If it is a severe dry eye that has a significant secondary inflammation because normal physiology has been compromised, I will also initially attack the inflammatory process while treating the underlying ocular surface drying. If, however, it is a non-inflammatory induced and not significantly inflamed expression of disease at the time, I'll target the underlying causative factors directly and not inflammation."

Dr. Roberts warns that much dry eye is really blepharitis. For these patients, physicians need to address their Meibomian glands that are pumping out abnormal secretions with either hot compresses or a thorough cleaning of the surface of the eyelids and lashes. "That, in combination with the tears, is going to dilute out the abnormal secretions," he says.

Dr. Roberts finds that lacrimal gland dysfunction, usually an inflammatory type, is the most common cause of dry eye in the patients he sees. These patients, he says, will also need more than artificial tears eventually, and it is important to tell them so. "Tears are a great first-line therapy, but for most people, dry eye is a progressive disease, so they start out with tears and eventually work up to need something more," says Dr. Roberts. "The drops are palliative, not therapeutic."

Experimentation is Required

Understanding that fact, of course, doesn't make it any easier to find the best dry eye drop for each patient, according to these clinicians. "There's no such thing as the ‘right tear for everyone,’ broadly speaking," says Dr. McCulley.

"Even with all the science, there's still a fair amount of trial and error in choosing a dry eye drop." agrees Dr. Roberts. "There are certain tears that certain people are going to find more comfortable than others. You have to take the time to figure out what the problem is. You can't avoid that," he says.

Dr. Asbell agrees, pointing out that differences in the viscosity of the various artificial tears and other traits that affect their ability to wet the ocular surface make some products more suitable for particular patients than others.

Dr. McCulley speculates that patient tolerance is partially related to the pH of their own tears and the pH of the drop. "If they match, great; if they are significantly different, patients tend to have symptoms of irritation."

The Preservative Factor

When it comes to the question of the presence of preservatives in dry eye drops, it seems that the individual patient's chemistry is again the deciding factor. Dr. McCulley says that many of the preservatives used in U.S. products are mild, but that even they can affect some patients.

However, Dr. McCulley points out that even preservative-free tears can have drawbacks. For one thing, they often come in smaller vials, making them potentially more difficult to manage. "And they are allegedly for one-time use, so it's more expensive," he says. "If patients don't follow the product label and try to use it more than once, then they have to be very careful about how that vial is handled between uses — not to get it overheated, not to get it contaminated."

Let the Tears Flow Freely

The most overlooked issue, Dr. McCulley believes, is hammering home to the patient the message that they should not wait until their eyes feel dry to use artificial tears. The most significant problem he finds with artificial tear replacement palliative therapy is that patients do wait until they feel a dry spot to use the tears. "By then," he says, "the horse is out of the barn. Now you have a dry spot and it tends to self-perpetuate." If the physician does not drive this point home, Dr. Mussolini warns, patients will quickly "fall off the wagon."

"If you don't spend time on patient education, sometimes the patients will use the drops for a day or two and then come back 2 weeks later and say the drops didn't really work," he says. "In our minds, we know exactly what we're saying, but you have to make sure the patient really understands." Make it clear that the patient should use their artificial tears regularly enough that he or she never feels the need for them, says Dr. McCulley.

Don't Rely on Drops Alone

However, it is crucial to make patients understand that they should not simply rely on artificial tears, or any other medication, to fix the problem of dry eye. Small changes in their environments can also ameliorate their symptoms. Dr. McCulley explains to patients that they need to avoid situations of low humidity, such as are found in desert environments, in the mountains, on airplanes and even those created by air currents from heating or air-conditioning units blowing across their faces.

Dr. Mussolini advises patients to lower the angle of their computer screens. "That decreases their palpebral fissure and minimizes exposure," he says.

Another point to educate patients on is simply the need for sufficient blinking. It's not just people who work on computers who may not blink frequently enough, Dr. McCulley points out, but anyone who engages in a great deal of close work.

Dr. Mussolini concurs. "Reading a book, watching movies — studies have shown that you blink less," he says. "We need to educate patients that as they're doing these things, they need to make an effort to blink a little more."

In addition to addressing the environment, some clinicians enlist the aid of neutraceuticals. Dr. McCulley says that he sometimes recommends that patients take an Omega-3 fatty acid supplement. "There's a lot of anecdotal information that suggests that Omega-3s are helpful. We have done a study with one of the commercial preparations and found strong trends that did not reach statistical significance suggesting efficacy," he explains.

Dr. Mussolini agrees that neutraceuticals can be valuable in alleviating dry eye, possibly when the patient has reached the moderate-to-severe stage of the disease. "Some good studies have shown that Omega-3 supplements have high amounts of gamma-linoleic acid, the precursor to prostaglandin E1, which helps to regulate the function of the lacrimal gland." Options for moderate to severe dry eye are limited and drops alone may be insufficient (see sidebar).

Offering Relief

While physicians may still be limited in how much relief they can provide to their dry eye patients, dry eye specialists maintain that they can do a lot by acknowledging that patients have a real problem and being willing to work with them to find the best treatment. "As I'm washing my hands or flipping through their chart, I'm asking the patient how their eyes feel, to make the diagnosis," explains Dr. Mussolini. "Are they gritty, sandy, any blurring or tearing? It's a simple question, and only takes a few seconds to ask."

And worthwhile, considering dry eye's ramifications for patients. "It is clearly associated with fluctuating vision," says Dr. Asbell. "People are blinking all the time, their quality of vision breaks down as the tear film breaks down over the ocular surface. So these are significant problems from a patient's perspective. It affects their ability to read, to do work, some of them to the point where they ask for disability from their job."

Artificial tears, Dr. Mussolini maintains, can help. "They are the mainstay of management across the full spectrum of dry eye disease." OM

Reference

1. Schiffman RM, Walt JG, Jacobsen G, Doyle JJ, Lebovics G, Sumner W. Utility assessment among patients with dry eye disease. Ophthalmology. 2003; 110(7):1412-1419.