Differentiating Dry Eye Types
This summer, a monumental study of dry eye disease was published in The Ocular Surface—TFOS DEWS II. In the previous Clinical Pearl, we summarized findings from its Diagnostic Methodology Report. This week, we’ll discuss how to most effectively determine dry eye disease type.
Last time, we discussed dry eye testing recommendations specified in the TFOS DEWS II Diagnostic Methodology Report.1 This included triaging questions, risk factors, a validated questionnaire, non-invasive tear film break-up time, osmolarity testing and ocular surface staining. Using these tools, you’ll be able to diagnose most cases of dry eye disease. However, the next step is to determine whether the patient has aqueous-deficient dry eye, evaporative dry eye or both.
Certain diagnostic tests are more helpful than others, when determining dry eye type. For example, decreased tear volume (meniscus height <0.2mm) is indicative of aqueous-deficient dry eye, whereas the presence of meibomian gland dysfunction or a deficient lipid layer is indicative of evaporative dry eye. Other indications of evaporative dry eye include lid margin drop-out, gland loss or displacement, abnormal or difficult expression, gland obstruction and vascularity.
Another diagnostic option that could help differentiate dry eye type is fluorescein or lissamine green staining. Fluorescein staining, for example, can be an accurate indicator of late-stage disease. Thus, it’s often best to pair this approach with one of the more specific tests outlined above.
1. Wolffsohn JS, Arita R, Chalmers R, et al. TFOS DEWS II Diagnostic Methodology report. Ocul Surf. 2017 Jul;15(3):539-74.