What Causes Dry Eye?

Ever wonder what causes dry eye?  It is estimated that 85-95% of all dry eye is actually related to Meibomian Gland Dysfunction.  So what are Meibomian Glands, and what causes them to be dysfunctional?  Meibomian glands are long, narrow glands that line your eyelids and produce the oily component of your tear film.  In our society, many of us simply don’t blink our eyes enough for the  Meibomian glands to function properly.  This is due to the screen-driven nature of our current existence, and our brain’s resulting FOMO, telling us not to blink or to blink less completely.  Many LASIK patients also suffer from dry eye as corneal nerves are severed during the procedure, thus the eyes are less sensitive to dryness and don’t signal the brain to blink enough.  To dive deeper into why this is important, let’s examine the anatomy of the tear film. 



Your tear film is actually comprised of three layers.  The thickest, middle layer of the tear film is watery and produced by the lacrimal gland. Each eye has one lacrimal gland that resides in the upper, outer portion of the eye socket.  The lacrimal gland also produces the volume of tears that occur when your eyes water from allergies or crying.  The mucin layer of the tear film lies closet to the eyeball itself, and is produced mainly by cells in the clear outer covering of the white part of the eye known as the conjunctiva.  The mucin layer makes the watery layer comfortable on the front surface of the eye.  The outer lipid layer, or oily layer of the tear film interfaces with the atmosphere. If there is not enough oil in the outer layer of the tear film, the tears evaporate off the eyes as soon as they are produced.  This most  often results in dry, gritty, sandy eyes, foreign body sensation, poor vision, and/or reduced contact lens tolerance.  Sometimes an annoying watery eye can result, as the eye struggles to keep moist by producing extra watery component of the tear film to compensate for the lost oils. This extra water often runs down the outside corner of the eye resulting in red, irritated skin.



We know that eyes require 100 nanometers of oil in the tear film to be comfortable and prevent evaporative dry eye.  During a dry eye evaluation, we actually measure the amount of oil in your tear film. We also measure and image your blinking, as well as the quality of oil in your tear film.  We image the Meibomian glands themselves, assessing their health and looking for atrophy, or drop out of the glands.  So what can be done about Meibomian Gland Dysfunction?



At Vision Source RIO we offer two in-office procedures.  Lipiflow places activators on the inside and outside of the eyelid itself.  The upper and lower lids are heated to the temperature of a warm shower in order to melt the clogged meibum, or oil, that backs up in Meibomian glands that aren’t functioning properly.  Then the meibum is gently massaged out of the eyes through the inflation and deflation of small pillows located within the activators themselves. Through a series of additional “homework” steps listed below, good quality meibum is produced and patients are re-taught the appropriate way to blink.  For many patients, this solves their dry eye issues.  However, some patients also have a rosacea component to their dry eye.  When this occurs, irritated dilated blood vessels choke off the Meibomian glands and prevent them from properly flowing.  In addition, many rosacea patients also have demodex, an overgrowth of normal flora mites on the eyelids themselves.  The demodex are also destructive to the meibomian glands. IPL, or Intense Pulsed Light therapy, is required in a series to tame the demodex overgrowth and treat the diseased blood vessels.  Through a combination of Lipiflow and IPL, plus the additional homework of moist heat mask, sleeping with a mask at night, omega 3 supplementation, increased water consumption, and limitation of caffeine and alcohol, most dry eye patients can experience relief.



Some other forms of dry eye may be due to inflammation, corneal damage, pterygium, or even Sjogren’s Syndrome.  These patients may require steroid eye drops, copious amounts of artificial tears, bandage contact lenses, amniotic membrane therapy, and/or autologous serum which is derived from a blood donation by the patient.  


Each patient’s dry eye results from a unique combination of factors, so treatment must be tailored to the situation and symptoms of each patient.  To find out which treatment may be appropriate for you or a loved one, make an appointment with Dr. Planitz today.


Dr. Planitz is an Optometric Physician specializing in the treatment of dry eye.