From viewing and imaging meibomian glands to measuring tear osmolarity and MMP-9, here’s how to detect this chronic condition.
|The OCULUS Keratograph 5M captures images of
the glands so they can be shown to patients.
|The InflammaDry by RPS detects elevated levels of MMP-9. Patients who have elevated MMP-9 in their tears are more likely to respond to anti-inflammatory therapy.|
|The OCULUS JENVIS Dry Eye Report shows the
results of all the OCULUS Keratograph 5M dry eye
examination and other examinations.
If you go to any optometric meeting or pick up any optometric magazine you will see numerous presentations and articles surrounding dry eye. Why all the interest? The answer is easy . . . opportunity.
According to the Beaver Dam Offspring Study and other sources, approximately 30 million people in the U.S. report symptoms consistent with Dry Eye Disease. To put this in perspective, the National Eye Institute estimates 2 million people over the age of 40 have macular degeneration and 2.7 million have glaucoma.
Dry eye diagnosis starts with a thorough case history and can be further evaluated by using one of the statistically validated dry eye questionnaires that assess patient symptoms. These questionnaires provide a quantifiable assessment of dry eye symptom frequency and the impact of these symptoms on vision.
Other commonly used and readily available objective tests for documenting and assessing the severity of Dry Eye Disease include slit lamp evaluation of cornea and conjunctiva, tear film break-up time, Schirmer testing, vital dye staining with fluorescein, rose bengal and lissaminegreen, tear meniscus and lid evaluation.
Here’s a look at newer and more sophisticated technologies available to aid in the diagnosis of Dry Eye Disease and in educating our patients.
MEIBOMIAN GLAND EVALUATION/IMAGING
Visualization of the meibomian glands is not anything new. We have done this for years by simply flipping the lids and using a transilluminator to visualize the glands. Today, we have three commercially available instruments for viewing and imaging the meibomian glands: the OCULUS Keratograph 5M and the LipiView II and LipiScan from TearScience. These instruments allow us to capture images of the glands and then show them to patients. This educational benefit is invaluable when discussing the chronic progressive nature of Dry Eye Disease with our patients and in monitoring for progression. While both instruments allow imaging of the meibomian glands, they do have some differences.
The OCULUS 5M Keratograph is a multifunctional instrument that in addition to meibography also allows evaluation of the lipid layer of the tear film, measurement of the tear meniscus, non-invasive tear break-up time and automatically classifies conjunctival redness. Other functions include corneal topography, keratoconus detection, contact lens fitting and external photography.
Another unique feature of the OCULUS Keratograph 5M is the OCULUS JENVIS Dry Eye Report. This one-page summary shows the results of all the OCULUS Keratograph 5M dry eye examination as well as the results of other examinations such as osmolarity, blink rate and the OSDI Dry Eye Questionnaire.
TearScience has two instruments for imaging the meibomian glands. The LipiView II allows practitioners to measure lipid layer thickness, image meibomian gland structure and evaluate blink dynamics. The LipiScan is a scaled-down version designed for the sole purpose of imaging the meibomian glands. Both instruments boast dynamic meibomian imaging (DMI), which uses dynamic illumination and adaptive transillumination. Each technology generates its own independent image of the glands which is then processed, displayed and combined to provide visualization of the meibomian gland structure.
TearLab is an in-office point-of-care diagnostic test that measures tear osmolarity. The testing can be conducted by a technician and uses a small sample of tears to determine tear osmolarity. A tear osmolarity >316mOsm/L indicates mild Dry Eye Disease. A difference of >8 mOsm/L is also indicative of Dry Eye Disease.
When used in conjunction with other methods of clinical evaluation, measuring the osmolarity of human tears can aid in the diagnosis and management of patients suspected of having Dry Eye Disease. While tear osmolarity cannot differentiate between aqueous deficient or evaporative dry eye, it does provide an objective measure of Dry Eye Disease with an indication of the severity.
Matrix metalloproteinase 9 (MMP-9), an important inflammatory marker associated with ocular surface disease, is a proteolytic enzyme produced by stressed epithelial cells on the ocular surface and is found to be elevated in approximately half of patients with dry eye. Elevated MMP-9 levels highly correlate with clinical exam findings in patients with mild to severe Dry Eye Disease.
The InflammaDry by RPS detects elevated levels of MMP-9. The single-use test uses a small sample of human tears, takes less than a minute to complete and delivers results in ten minutes. A positive InflammaDry test result indicates that there is clinically significant inflammation of the ocular surface, with MMP-9 â‰¥ 40 ng/ml.
This testing can be very valuable in determining treatment modality. Patients who have elevated MMP-9 in their tears are more likely to respond to anti-inflammatory therapy, while patients without elevated MMP-9 are much more likely to benefit from supportive management with artificial tears or punctal occlusion.
Dry eye is reaching near epidemic proportions. Some of the new technologies can be a great adjunct to the case history and traditional diagnostic tools. Implementation of these new technologies can have a dramatic impact on our ability to educate, treat and manage our patients with Dry Eye Disease.
Carl H. Spear, OD, MBA, FAAO, and Katie Gilbert Spear, OD, MPH, have a multi-location group private practice in the Florida Panhandle.
|Dry Eye Questionnaires
Ocular Surface Disease Index (OSDI)
The OSDI analyzes patient responses across three different subscales: vision-related function, ocular symptoms and environmental triggers. The OSDI is effective in discriminating between normal, mild to moderate and severe Dry Eye Disease as defined by both physician’s assessment and a composite disease severity score.
Standard Patient Evaluation of Eye Dryness (SPEED)
5-Item Dry Eye Questionnaire (DEQ-5)