dry eye

Dry Eye Management: Your 10 Step

Approach to Making the Correct Diagnosis

BY SCOT MORRIS, O.D., F.A.A.O.
Conifer, Colo.

Why is it important to make the correct diagnosis?

The implications of making an incorrect diagnosis in any disease, much less diseases more common to our practices, are widespread. Now, consider the costs. Incorrect diagnosis typically leads to an incorrect or incomplete treatment regimen, which can lead to:

► temporary or even permanent anatomical and functional changes that may worsen the disease state.

► increased financial demands on the patient, third-party managed care and even your practice. Couldn't you better utilize your practice time and energy in other areas, or on other patients?

► a loss of esteem or respect from the patient, which may ultimately negatively impact the reputation or health of your practice, your community, or, on a much larger scale, your profession.

► a lost patient, which is a lost opportunity to make a difference in this patient's life. Remember: That's why we went to school all those years.

Making the right diagnosis can be a daunting task. The answers aren't always as obvious as "you are a -2.00 sphere, and glasses will allow you to see road signs again."

Regardless of the ocular surface disease (OSD) you're dealing with, the same general diagnostic protocol applies.

Here, I discuss this protocol.

STEP 1: Listen

The patient history typically tells most of what you need to know. Patients tell you their symptoms, what makes them feel better and what they expect from you in terms of care.

Pay specific attention to their chief complaint as it relates to their daily visual function. It takes active listening and a series of well-thought-out questions — covering such areas as environmental factors, time of day and severity of symptoms — to develop a targeted approach to the rest of your clinical exam.

For example, a patient who reports that his eyes are "glued shut" in the morning and suffers from frequent tearing when exposed to moving air from such sources as wind or ventilation systems most likely has evaporative disease second-ary to meibomian gland dysfunction. (Etiology: poor or absent lipid secretion leads to poor lubrication and increased evaporation, which may lead to subsequent reflex tearing.)

Simply listening to patients and thinking about what disease conditions may be causing their symptoms is extremely helpful in designing the rest of your clinical exam.

STEP 2: Think systemic

In addition to the obvious systemic medications, such as oral antihistamines, beta-blockers and diuretics, which cause decreased secretions throughout the body, ask about the patients' overall health.

For instance, how is her immune and hormone status? Does she have any inflammatory diseases? Does the patient have any systemic allergies or a history of ocular trauma or surgery? What are her nutritional habits, and does she take any nutritional supplements?

The eye is just one end organ influenced by the overall health of the rest of the body. Therefore, our job is to not just to be the eye doctor, but doctor as well. Ocular diagnosis may be one of many related systemic manifestations of some larger disease process, such as diabetes. Think about what is going on with the person as a whole, and develop treatment strategies based on their systemic health. (Find a list of common medications that cause dry eye and common systemic conditions associated with dry at www. optometric.com/arti cle.aspx?article=100509.)

STEP 3: Slow down

Don't rush to examine the details before you look at the big picture. Assess what else you see before you use your slit lamp.

Factors to consider:

► Does the patient have facial abnormalities, such as rosacea, that could lead to dry eye?

► How often does he blink (without you asking him not to blink)? Does he blink abnormally? What is his normal blink rate during conversation?

► Do his eyelids close completely? What is his lid and punctal apposition? Could any of these features suggest tear evaporative issues, poor lipid deposition or improper tear drainage?

► How do his lid margins and conjunctivae look? Significant hyperemia is usually related to inflammatory issues.

STEP 4: Work the same way

Develop a strategy, and perform your diagnosis the same way every time. This will prevent you from missing small details that are key to the diagnosis.

Consider:

► Lids. Most forms of OSD involve the lid margin. Do you see seborrheic blepharitis, bacterial blepharitis or both? Do you see signs of acute or chronic inflammation? These observations may help guide your treatment strategy.

► Palpebral and bulbar conjunctiva. How much hyperemia do you see? Do you see follicles or papillary changes suggestive of inflammatory disease? Is the condition acute or chronic? Because allergies are just a component of inflammation, treatment won't really differ that much from other forms of OSD, except for the scale or level at which you need to treat.

► Cornea. Observe (without stain). Do you see erosions, elevations, depressions, dystrophies, etc., that can affect the way the tear film flows across the cornea?

STEP 5: Stain(s)

Now stain. First use lissamine green, and wait a minute or two before you observe the cornea. This stain takes time to color mucin and membranes. Look for patterns. A band-like pattern across the inferior third of the cornea usually means either incomplete blink or a closure issue (which you should have already noted). Staining at four o'clock and eight o'clock are related to lid margin disease.

Now, repeat this same process with sodium fluorescein (not Fluress [fluorescein sodium/benoxinate hydrochloride]) and look under the blue filter. Remember that dry eye, like all OSDs, affect more than just the cornea. Examine the conjunctiva and lid margin along the gray line. The intrapalpebral conjunctiva typically shows lissamine staining earliest in the disease.

STEP 6: Think balance and stability

The tear film is a complex and intricate balance of many components including secreted fluid, ions, proteins, glycoproteins, and lipids that lubricates and protects the ocular surface. Any imbalance can be a key sign of a specific problem.

Several methods of tear film stability testing exist. Interpretation of tests may be beyond the scope of this article, but if the blink rate is less frequent than the tear break-up time (TBUT), the patient is symptomatic. Note that any of these issues can lead to a faulty TBUT:

► a heavy or contaminated lipid layer.

► insufficient aqueous-mucin gel layer leading to contact of the lipid and the ocular surface.

► an ocular surface with faulty or absent glycocalyx.

STEP 7: Assess tear volume

If the patient's Schirmer's test score is greater than 5mm, and he is non-symptomatic, then move on. If it's less than five, the patient probably has dry eye. The general principle is: If the score is low, it's usually always low (<5 mm).

STEP 8: Check aqueous outflow

Though fairly uncommon, don't overlook aqueous outflow disorders. In cases of epiphora, for instance, evaluate the patency of the punctum as well as both the upper and lower canaliculi. To check for patency, you may need to use the Jones test or irrigation.

STEP 9: Observe the meibum

The lipid-based substance known as the meibum is largely responsible for the rate of tear evaporation. The lipid also serves as a vehicle for many types of inflammatory mediators. Do you see atrophies, clogged or misshaped glands? Can you express meibum? What's its appearance? Can you grade meibum viscosity and clarity based on established grading criteria? Are your findings consistent with systemic and other ocular findings?

STEP 10. Put it all together.

Now put everything you have observed together, and look for patterns, so you can prescribe the best treatment. Do your observations fit with the patient's symptoms? If not, ask him more questions.

Remember: If you can't identify the cause of symptoms and develop a game plan to resolve them, your patient is likely to become someone else's patient.

Making the correct diagnosis regarding ocular surface disease (OSD) is challenging, requires patience, observation, a little discipline and an open mind that is eager to learn. By implementing the aforementioned 10 step protocol, you may avoid the aforementioned pitfalls associated with an incorrect or incomplete treatment regimen. OM

Dr. Morris practices at Eye Consultants of Colorado in Conifer, Colo. He's the founder of Morris Education & Consulting Associates, a professional continuing education and consulting firm. e-mail him at smorris@eyeconsultantsofco.com.