Stephen M. Cohen, OD

Dry eye is commonly characterized as a self-perpetuating cycle of tear film instability and ocular surface desiccation. Biological or environmental factors may lead to destabilization of one or more of the tear film’s primary components — lipids, aqueous, mucins — or the thin glycocalyx layer. The result is a more-rapid-than-normal tear film break-up time (TFBUT); areas of the tear film may evaporate before the replenishing blink, leaving the surface of the eye unprotected. Through prolonged contact with air and environmental particulate matter, ocular surface cells may become desiccated and die. The glycocalyx, which is a natural meshwork of mucins and other particles that is essentially the glue between the hydrophobic corneal epithelium and the tear film, cannot do its job if surface cells are damaged. Ultimately, the ability of the tear film to adhere to the corneal epithelium is compromised, increasing the rate of TFBUT and intensifying surface exposure.

Dry eye syndrome, also known as ocular surface disease (OSD), affects as many as 60 million Americans. Many patients with dry eye syndrome remain undiagnosed and untreated, and many others treat their condition with less-than-optimal over-the-counter drops. In a busy eye care practice it can be difficult to accurately diagnose this disease.