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Most practitioners start with patient history when diagnosing dry eye
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A: Start with history
Eric E. Schmidt, OD: Diagnostic tests for ocular surface disease are not only valuable to help detect the presence of the condition, but also for determining the severity of the disease. These tests are clinically useful in helping the doctor differentiate between the types and causes of dry eye and in determining the effectiveness of therapy.
Initially, I like to use a patient questionnaire. This gives me insight into the patient’s complaints and helps alert me to the presence of the disease.
---Fluorescein imaging allows the practitioner to determine the amount and severity of staining of the cornea and conjunctiva, while also providing a clear image of the height of the lacrimal lake.
Next, I stain the eyes with a sodium fluorescein (NaFl) strip and look for staining of the cornea and conjunctiva, making note of both the presence and severity of the staining. The NaFl dye also allows me to easily visualize the height of the lacrimal lake. I also feel it is important to discern the tear break-up time to determine if the condition is evaporative in nature.
I use the phenol red thread or Schirmer’s test to give me an estimate of tear production. These two tests are more useful for determining the efficacy of treatment than for diagnostic purposes.
Finally, I instill rose bengal stain to assess the magnitude of necrosis and inflammation on the ocular surface.
After therapy has been initiated, each of these tests should be repeated on each visit so I can see whether the treatment is improving these objective findings.
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Eric E. Schmidt, OD, is director of the Bladen Eye Center, where he specializes in the treatment of ocular disease. He can be reached at PO Box 2589, Elizabethtown, NC 28337; (910) 862-4258; fax: (910) 862-2057; e-mail: Kenziekate@aol.com. Dr. Schmidt has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
A: Start with history
Barbara Caffery, OD, MS: Like many other chronic diseases of the eye, the diagnosis of dry eye requires multiple testing and clinical judgment. The most important and first diagnostic test is the history. Most clinicians rely on a questionnaire to ascertain which symptoms are present, how severe they are, how long they have been present, the presence of dryness of other mucous membranes, which circumstances exacerbate the symptoms and what brings relief.
The most common questionnaire used to date is the McMonnies questionnaire. It can be graded and scored to help in the diagnosis. Several groups are attempting to create derivative questionnaires that may be better at diagnosing mild to moderate dry eye. The McMonnies questionnaire tends to be better at determining moderate to severe dry eye.
If the dryness is associated with dry mouth, the practitioner must be suspicious of the possibility of a systemic origin, such as Sjögren’s syndrome. Further questions should include the family history of autoimmune disease and the presence of joint pain and fatigue.
The objective testing should begin with an observation of the ocular surface and the tear film using the biomicroscope with very low light. Look for debris in the tear film and for the general quality of the blink.
A Schirmer’s test is performed next without anesthetic. Findings of less than 5 mm wetting after 5 minutes can indicate dry eye.
Next, add fluorescein in as standard a method as possible. Wet a fluorescein strip with nonpreserved saline and apply a small amount to the inferior tarsal conjunctiva. Allow the patient to blink normally, and return to the slit lamp. Using a cobalt blue filter and yellow wratten filter, observe any staining of the cornea, and record the findings on a diagram. The healthy cornea stains very little. Next, measure the tear break-up time by having the patient blink once, and record the time of the first break-up. Tear break-up times of less than 10 seconds are considered suspect.
--- Lissamine green staining does not cause stinging for the patient, but requires quick observation after insertion.
The condition of the conjunctiva can be observed using one of two vital stains: rose bengal or lissamine green. Both must be used in liquid form to obtain good results. Rose bengal is more readily available but does cause considerable discomfort in patients with dry eye. Lissamine green does not cause stinging but must be observed quickly after insertion. Both are observed with white light. A normal conjunctiva does not stain with either dye.
Finally, the condition of the lids must be observed. The presence of lash cuffing or flaking should be recorded. The meibomian glands should be expressed and the percentage of functional glands and the quality of the secretions should be observed.
Following this disciplined and comprehensive work-up, the practitioner should be able to confirm or deny the diagnosis of dry eye. The degree of dryness can be determined by the severity of symptoms and the condition of the cornea and conjunctiva as determined by vital staining. Finally, the cause of dryness may be suggested. For example, patients with rather normal ocular surfaces and Schirmer’s tests but with blepharitis and meibomian gland dysfunction likely have lid-related ocular surface disease. Patients with low Schirmer’s tests, dry mouth and a history of autoimmune disease more likely have Sjögren’s syndrome.
- Barbara Caffery, OD, MS, is in private practice. She can be reached at 77 Bloor St. W, Ste. 1409, Toronto, Ontario, Canada M5S 1M2; (416) 961-6671; fax: (416) 961-7958; e-mail: Bcaffery@RUISSO.org. Dr. Caffery has no direct financial interest in the products mentioned in this article, nor is she a paid consultant for any companies mentioned.
A: Start with history
Jeffrey P. Gilbard, MD: As an eye becomes dry, the tear film loses water and tear film osmolarity increases (first milestone). This increase in osmolarity dehydrates the eye surface and causes symptoms. The first morphological change is a decrease in conjunctival goblet cells and a desquamation of conjunctival epithelial cells (second milestone). Only much later in the natural history of dry eye disease do corneas begin to desquamate (third milestone). When the superficial corneal cells are lost, the remaining corneal cells lack cell surface glycoproteins (fourth milestone).
Diagnostic tests directed at the earliest milestones of disease are the most sensitive. For this reason, the history is the most sensitive “diagnostic test.” Patients with dry eye complain of sandy-gritty irritation or dryness that gets worse as the day goes on. Additional features of the history are chronicity, symptoms for greater than 6 months and gradual onset. Tear osmolarity measurement provides useful quantification if it is available. The purpose of the exam is to determine the cause of dry eye: decreased tear production (lacrimal gland disease or decreased corneal sensation) or increased evaporation (meibomian gland dysfunction or large palpebral fissure width).
- Jeffrey P. Gilbard, MD, is the medical director of the Cornea & Vision Correction Center, is clinical assistant professor at Harvard Medical School and is founder and chief executive officer of Advanced Vision Research. He can be reached at Advanced Vision Research, 7 Alfred St., Ste. 330, Woburn, MA 01801; (781) 932-8327; fax: (781) 935-5075; e-mail: info@theratears.com. Dr. Gilbard has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
A: Start with history
Arthur B. Epstein, OD: Dry eye is diagnosed as much by patient symptoms as clinical findings. Hence, the first and most important part of a diagnostic work-up is a detailed clinical history. For insurance and medicolegal reasons, it is important to obtain objective findings of this largely subjective disorder. Corroborative findings are especially important if punctal occlusion is contemplated.
Testing for dry eye ranges from the simple to the overly sophisticated. Surprisingly, I find the simplest tests the most valuable. Because most dry eye has an evaporative component, I always examine the lids first. Signs of meibomian gland inspissation and lid inflammation are highly suggestive. Rose bengal staining patterns are useful for identifying the cause of dry eye. Exposure zone staining occurs in the intrapalpebral area and corresponds to aqueous or mucin deficiency. Inferior staining, sometimes below the lower lid margin, is associated with meibomian gland dysfunction and is caused by the pooling of bacterial toxins and abnormal meibum. Lissamine green is a recently introduced rose bengal substitute that causes less discomfort.
Although much maligned, Schirmer’s testing with and without anesthesia is an important documentary test and should be performed on every dry eye patient. It objectively corroborates patient symptoms and also provides a baseline for future comparison.
Finally, because symptoms are so important in this disorder, it is important to remember the success of any therapy is best judged by patient response.
- Arthur B. Epstein, OD, is director of the contact lens service of North Shore University Hospital at the New York University School of Medicine and is an adjunct assistant professor at the North Shore University College of Optometry. He can be reached at North Shore Contact Lens and Vision Consultants, P.C., 1025 Northern Blvd., Ste. 94, Roslyn, NY 11576, (516) 627-4090; fax: (516) 627-4169; artepstein@ibm.net. Dr. Epstein has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
A: Tear lake exam
William D. Mathers, MD: Tests for dry eye can be divided into two categories: those that are available to most clinicians (tear lake, rose bengal, fluorescein washout, and Schirmer’s test) and those that are more difficult and used primarily for research (osmolarity, fluorophotometry, evaporation and impression cytology). Examination of the tear lake, an underused method of assessing tear volume, should be performed without slit-lamp illumination.
Rose bengal stain is not specific for dry eye and is highly variable. Fluorescein washout will give a rough estimate of tear flow, but reflex tearing is hard to avoid and makes the test difficult to interpret. Schirmer’s without anesthestic tests reserve capacity of the lacrimal system with a reasonably standard stimulus and is quite reliable for estimating reduced capacity if performed carefully. Schirmer’s test with anesthestic is not generally useful because it does not measure basal tear flow, but rather the hybrid stimulations resulting from the lid margin, lashes and partially anesthetized conjunctiva. Although all four of these tests can be used easily in any clinic setting, I particularly recommend evaluation of the tear lake and Schirmer’s test without anesthestic.
Osmolarity is the single best tear for dry eye and is much easier to perform now that an easy-to-use instrument is commercially available from Norwood, Mass.-based Advanced Instruments Inc. Fluorophotometric tear flow is highly accurate and is not difficult to perform, but the instrument is expensive. Evaporation is used only by research laboratories, because the equipment is not available commercially. Impression cytology can be performed easily, but its interpretation remains difficult.
Therefore, I would recommend that a tear lake examination and Schirmer’s without anesthetic be performed routinely. Other tests can be added, depending upon the interest and expertise of the clinician.
- William D. Mathers, MD, can be reached at Oregon Health Sciences University, 3375 SW Terwilliger Blvd., Portland, OR 97201-4197; (503) 494-3000; fax: (503) 494-3929; e-mail: mathersw@ohsu.edu. Dr. Mathers has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
A: Start with history
John L. Schachet, OD: We begin by taking a good history using a symptom checklist as well as a documented history taken by our technicians and reviewed by one of our doctors. Next, we perform a careful corneal and conjunctival biomicroscopic examination with and without fluorescein, looking at the tear break-up time and evaluating the tear meniscus. Then, we perform a phenol red thread test followed by a lissamine green or rose bengal test. Finally, we perform a collagen test, whereby we plug all four puncta and evaluate the need for further punctal/lacrimal occlusion over the following 10 to 14 days.
- John L. Schachet, OD, is in private practice and is a former adjunct professor at the Southern California College of Optometry. He can be reached at Eyecare Consultants, 8586 E. Arapahoe Rd., Ste. 100, Englewood, CO 80112; (303) 771-4221; fax: (303) 721-7759; e-mail: Jschachet@aol.com. Dr. Schachet has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
A: Combination of tests
Michael A. Lemp, MD: The diagnosis of dry eye depends not on one test but on a combination of tests. The most commonly available clinical tests that are helpful in making this diagnosis are as follows:
- A Schirmer’s test without anesthetic. Results of 5 mm or less at 5 minutes without anesthetic in both eyes suggest an aqueous tear deficiency. Serially consistent results less than 5 mm are highly suggestive of this diagnosis.
- Rose bengal staining of the ocular surface.
- Fluorescein staining of the cornea.
- Tear film break-up without anesthetic. Results of less than 10 seconds suggest an unstable tear film.
- Careful examination of the meibomian gland orifices of the lids with careful pressure approximately 1 mm away from the orifices. It should be possible to express clear meibomian fluid from the majority of these orifices. If the fluid is turbid, coagulated or not expressible, this is suggestive of meibomian gland dysfunction (evaporative dry eye), which is a very common condition.
- Michael A. Lemp, MD, is the clinical professor of ophthalmology at Georgetown University. He can be reached at the University Ophthalmic Consultants of Washington, 4910 Massachusetts Ave., NW, Ste. 210, Washington, DC 20016; (202) 686-6800; fax: (202) 686-6668. Dr. Lemp has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
A: Start with history
Albert M. Morier, OD: The first test is a good case history with a sensitive ear to a patient’s complaints to identify those who are at the highest risk for dry eye. This includes systemic conditions, age, contact lens wear, medications and computer usage. I will then do a slit-lamp evaluation and use a narrow beam of dim light (so as not to instigate tearing) to evaluate the height of the tear meniscus on the lower lid.
I will look on the cornea with white light and fluorescein for epithelial defects and tear break-up times. I will inspect the lids so as not to miss blepharitis and meibomianitis, which may be the real cause of the patient’s symptoms. I then perform a phenol red thread test for a fast 15-second evaluation of aqueous deficiency. If this shows a normal result, I may choose to do a Schirmer’s test (Type II, with anesthestic). Both of these tests have high false-negative results, so duplication is a good idea.
The ultimate test is to use collagen inserts and gauge the patient’s response. I usually place two or three inserts in each of the inferior puncta for full blockage and tell the patient that this may only last for 2 to 3 days but may last up to 5 days. These collagen inserts should be a little snug when you place them. The patient is advised to notice any improvement in comfort or increased wearing time of his or her contact lenses.
- Albert M. Morier, OD, is an instructor of clinical ophthalmology at Albany Medical College. He can be reached at the Lion’s Eye Institute, 35 Hackett Blvd; Albany, NY 12208; (518) 355-0956; e-mail: amorier1@nycap.rr.com. Dr. Morier has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.