Deciphering the Dry Eye Code

A framework for diagnostic and treatment protocols

The tear film is the most important refracting surface of the eye, and this is very important in our practice where we’ve performed more than 30,000 laser vision correction procedures and more than 20,000 cataract surgeries and have approximately 90% conversion to femtosecond laser-assisted cataract surgery and 53% conversion to premium IOLs. Our success is based on our active management of ocular surface disease, i.e., dry eye, along with astigmatism, macular pathology, posterior capsular opacification, and IOL calculations, all of which factor into our overall patient satisfaction.

Dry eye is a complex disease, but our understanding of it as a profession has been improving. As a result, it’s possible to distill what is currently known down to key points we can use to create and guide our diagnostic and treatment protocols.

Dry Eye Facts, Simplified

► Dry eye is a multifactorial disease accompanied by increased osmolarity of the tear film and inflammation of the ocular surface.¹

► The disease classification developed by the International Dry Eye Workshop (DEWS)¹ is a way to stage dry eye severity in the clinical setting. I think of it like this: Level 1 is conjunctival staining; Level 2 is corneal and conjunctival staining; Level 3 additionally involves filamentary signs on the cornea; and Level 4 additionally involves conjunctival scarring.

► Meibomian gland dysfunction (MGD), a progressive disease that can lead to meibomian gland atrophy,² is present in 86% of cases of dry eye.³

► Dry eye risk factors include the following:

• Age

• Female gender (postmenopause)

• Poor diet (low in omega-3 fatty acids, high in bad omega-6 fatty acids)

• Autoimmune disease (thyroid, lupus, rheumatoid arthritis, diabetes)

• Sjögren’s Syndrome

• Low blink rate (due to systemic disease, e.g., Parkinson’s, or digital device use)

• Medications (antihistamines, diuretics, antidepressants/antianxiety)

Mitchell A. Jackson, MD
Jacksoneye Lake Villa, Ill.

My Personal Approach

With the key dry eye facts and risk factors in mind, I approach the care of each patient in the following manner:

► Review patient questionnaire. We have our patients complete the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire. I’ve modified it to include allergy-related questions as a first step toward determining the precise causes of their symptoms.

► Analyze results of point-of-care diagnostic testing. There are many clinical measures for evaluating and monitoring dry eye, including:

• Tear secretion (Schirmer’s test)

• Corneal/conjunctival vital dye stains

• Tear breakup time

• Lipid layer imaging (LipiView, TearScience)

• Meibomian gland structure imaging (LipiView II/Dynamic Meibomian Imaging [DMI], Tear Science)

• Impression cytology (goblet cell analysis)

• Tear osmolarity (TearLab)

• MMP-9 activity (InflammaDry, RPS)

• Sjögren’s syndrome test (Sjö, Valeant)

• Ocular allergy testing (Doctor’s Allergy Formula, Bausch + Lomb)

I don’t have every available diagnostic test and device in my practice, but in addition to vital dye staining, I’ve found InflammaDry, TearLab osmolarity testing, LipiView, and Doctor’s Allergy Formula to be very useful in assessing the overall ocular surface status.

InflammaDry is a rapid point-of-care test. Our technicians have no problems performing it. The test identifies elevated levels of the inflammatory biomarker matrix metalloproteinase 9 (MMP-9) in the tear film with high sensitivity and specificity. Inflammation isn’t a factor in every patient’s dry eye, so it’s important to know when it is so we can treat it. A positive result is MMP-9 ≥ 40 ng/ml, and it indicates, based on the DEWS classification, at least Level 2 severity (See Figure 1). InflammaDry is a useful way to monitor the effects of treatment as well.

Figure 1: MMP-9 levels in the tear film help to identify dry eye severity.

Several studies have shown that a significant number of patients, including those coming in for cataract or refractive surgery, have signs of ocular surface disease but are asymptomatic.^4,5 It’s up to the doctor to look for the signs.

Tear osmolarity testing is an excellent predictor of disease severity.⁶ Two numbers are crucial in identifying abnormal osmolarity: 1) If the highest reading of the two eyes is >308 mOsm/L, it indicates loss of homeostasis and pathogenesis for ocular surface disease; and 2). An intereye difference of >8 mOsm/L is a hallmark of tear instability. It’s important that patients don’t use drops for at least 1 to 2 hours before the osmolarity test.

The LipiView II interferometer for detecting MGD is also part of our dry eye workup, and we’re in the process of implementing the new DMI capability. This instrument quantifies the lipid layer of the tear film with sub-micron precision and also shows if patients are partial blinkers, which we can help them to change. DMI improves assessment of gland structure. Seeing the degree of gland dropout is essential to knowing the extent of MGD progression so expectations can be set.

Finally, we also utilize the Doctor’s Allergy Formula point-of-care skin test, which takes the guesswork out of determining whether allergy is or isn’t playing a role in a patient’s ocular surface disease. Also, positive skin testing helps validate any prior authorization that is needed for prescribed topical antihistamine and/or steroid eye medications.

During a patient’s initial evaluation, I like to prescribe at least one treatment to move the health of the ocular surface in the right direction. I typically follow up 6 weeks later to see how he or she is doing, and tear osmolarity is my main objective test at that visit.

The tear film is the most important refracting surface of the eye.

► Prescribe, titrate treatment based on the diagnostic testing.

• For patients who need ocular allergy treatment, I prescribe an H1 receptor-specific topical medication, such as Lastacaft (alcaftadine ophthalmic solution 0.25%, Allergan) or Bepreve (bepotastine besilate ophthalmic solution 1.5%, Bausch + Lomb), which have a lower dry eye side effect than others that are non-specific.

• To lower tear osmolarity, I recommend a hypotonic artificial tear, such as Blink Tears (Abbott Medical Optics). Refresh Optive (Allergan), or TheraTears (Akorn).

• To control inflammation, I prescribe pulsed topical steroids or Restasis (cyclosporine ophthalmic emulsion 0.05%, Allergan), which inhibits T-cell activation and decreases MMP-9 activity.⁷ Restasis has also been shown, with continued use, to increase tear production regardless of when in the disease process it’s initiated.⁸ Topical lifitegrast (Shire) may also be available in the near future to control inflammation based on the recent OPUS-3 clinical studies.

• For MGD, I’ve found that warm compresses, lid scrubs, and low-dose doxycycline can be beneficial. We also use LipiFlow thermal pulsation therapy in our practice, the effects of which have been shown to last for up to 1 year.⁹

• I add nutritional supplementation where needed. While many good products are available, my preference is HydroEye (ScienceBased Health) due to the research behind it.¹⁰ Also, many patients prefer it and report that it does not have a fish taste.

Our attention to the ocular surface in this manner has been one of the most significant contributors to patient satisfaction in our busy surgical practice. ■

References