In 2007, the International Dry Eye Workshop (DEWS)¹ revised its definition of dry eye disease. The new definition — “Dry eye is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface.” — reflects an improved understanding of the condition. The addition of the word “multifactorial” is relevant not only to treatment but also to diagnosis, because dry eye manifests differently among patients. Therefore, as clinicians, we need to be on the lookout for several signs and symptoms. New diagnostic tools, in conjunction with those that were previously available, are a big help. They enhance our ability to diagnose dry eye efficiently and precisely. They can also help motivate patients to be active participants in their treatments, driving home the point that dry eye is a medical condition.

USE EVERY DIAGNOSTIC TOOL AVAILABLE

Another addition to the DEWS definition of dry eye, “visual disturbance,” makes perfect sense to those of us who’ve noticed it early in a patient’s visit, at the phoropter. Some patients have trouble deciding which lens is better until they purposefully blink, which alerts me right away that we’re likely to uncover other symptoms and signs of dry eye. To identify dry eye in our practice, we use all of the available means of diagnosis.

• Case history and questionnaire: Eliciting dry eye-related complaints begins with a thorough case history, including questions about contact lens wear and artificial tear use. A significant number of contact lens patients report some kind of compensating behavior, such as rubbing their eyes or removing the lenses before the end of the day, and many think that’s normal. We know that it doesn’t have to be. In addition, before patients see a doctor in our practice, they complete a SPEED questionnaire, which typically takes less than a minute. When we see a score of six or above, it’s another indication that we’ll be exploring dry eye further.
• Slit lamp examination: Frothing near the lower lid margin is a sign of dry eye (Figure 1A). Vital dye staining (Figure 1B) is part of our workup as well. It’s important to use two stains, either lissamine green and/or rose bengal and/or fluorescein strips. Don’t rely on the fluorescein drop to check IOP because it tends to flood the cornea rather than staining the problem areas. In my experience, rose bengal shows up better on the cornea, and lissamine green shows up better on the conjunctiva. At the slit lamp, we also evaluate the meibomian glands (Figure 1C). We express each one of them to see if the oil is healthy, i.e., clear and smooth looking, or problematic, with a look more like toothpaste. A capped gland is a sure sign of dry eye disease.



• Advanced testing: Our dry eye workup includes two point-of-care tests, the TearLab Osmolarity System (TearLab) and InflammaDry (RPS), as well as dynamic ocular surface imaging. The osmolarity test is CLIA-waived, but to be reimbursed for it, a CLIA Certificate of Waiver is required, though not difficult to obtain. Osmolarity is measured using a tiny sample of tears. Results have been shown to be a reliable metric for diagnosing and classifying dry eye disease.² Osmolarity values exceeding 308 mOsms/L are indicative of dry eye. In addition, the greater the inter-eye variability, the more likely disease is present.

InflammaDry is also a CLIA-waived test. Results are obtained in 10 minutes and are easy to interpret. A red line is positive (>40 ng/ml of MMP-9) and a blue line is negative. Results provide a quantifiable value representing the amount of matrix metalloproteinase-9 (MMP-9) in the tears. MMPs are proteolytic enzymes produced by stressed epithelial cells on the ocular surface, and MMP-9 is a marker for inflammation. The test has been shown to significantly and positively correlate with corneal fluorescein staining scores and abnormal superficial corneal epithelia as seen with confocal microscopy.³

Several ocular imaging devices can be used to diagnose dry eye, including the Keratograph 5M (Oculus) corneal topographer, the LipiView II Interferometer and LipiScan (both from TearScience). These instruments noninvasively assess parameters, such as tear break-up time, the lipid layer of the tear film, blink rate, and meibomian gland structure.

DRY EYE DISEASE DOESN’T DISCRIMINATE

Finding the patients in our practices who would benefit from dry eye treatment — they’re definitely there — also requires us to realize that anyone can be affected. Dry eye is no longer just an older person’s problem. Younger people are suffering, too. Because we’re living in a digital era, constantly looking at screens, we’re just not blinking as often. The decreased blink rate increases tear film evaporation, which leads to discomfort and likely progression of disease.

Our contact lens wearers should also be an area of focus. It’s widely accepted that approximately 16% of contact lens users permanently discontinue wear,⁴ and some studies and surveys find an even higher percentage.^5-7 Regardless of the number of dropouts, the primary reason for discontinued wear is without fail dryness and/or discomfort. A secondary reason is usually found to be poor quality of vision. Given the many advances in lens materials and designs in recent years, one wonders why we still see high dropout numbers, not to mention the affect it has on a practice’s bottom line. I think it speaks directly to dry eye.

To help all of our patients struggling with dry eye to get relief from their symptoms, and to restore the health of the ocular surface, we have to start with diagnosis. That means listening to our patients’ complaints, digging deeper to find the cause of the complaints, closely evaluating the ocular surface, and using all of the available resources in the process.

REFERENCES

1. The definition and classification of dry eye disease: report of the Definition and Classification Subcommittee of the International Dry Eye WorkShop (2007). Ocul Surf. 2007;5(2):75-92.
2. Lemp MA, Bron AJ, Baudouin C, et al. Tear osmolarity in the diagnosis and management of dry eye disease. Am J Ophthalmol. 2011;151(5):792-798.
3. Chotikavanich S, de Paiva CS, Li DeQ, et al. Production and activity of matrix metalloproteinase-9 on the ocular surface increase in dysfunctional tear syndrome. Invest Ophthalmol Vis Sci. 2009;50(7):3203-3209.
4. Nichols JJ. 2010 annual report on dry eye diseases. Contact Lens Spectrum; July 2010.
5. Richdale K, Sinnott LT, Skadahl E, Nichols JJ. Frequency of and factors associated with contact lens dissatisfaction and discontinuation. Cornea. 2007;26(2):168-174.
6. Giannoni AG, Nichols JJ. 2012 annual report on dry eye diseases. Contact Lens Spectrum; July 2012.
7. Pritchard N, Fonn D, Brazeau D. Discontinuation of contact lens wear: a survey. Int Contact Lens Clin. 1999;26(6):157-162.

Dr. Schaeffer is in practice at Schaeffer Eye Center, a comprehensive primary eyecare practice with 17 locations throughout Alabama.