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štvrtok 15. decembra 2011

The Patient's Guide to Dry Eye Syndrome: Meibomian Gland Dysfunction

One of the most common types of dry eye I see is a direct result of clogging of the tear glands that line the upper and lower eyelids.  This type of dry eye is more common in younger patients and men than other etiologies.  If you are having dryness and also experiencing:

  • itching, redness, or irritation along your lash line
  • small white/yellow bumps along your lid
  • recurrent styes
  • thick, hazy tear film intermittently between blinks
  • suffer from rosacea
then Meibomian Gland Dysfunction (or also called blepharitis!) is likely the culprit.  Let's take a closer look at the anatomy of the lid to understand what is going on.

The meibomian glands are sebaceous (or oily secretion) glands that run vertically through the eyelids.  Their opening is just inner to the eyelashes.  The function of these  glands is to secrete the oily "top coat" of the tears, that helps prevent the tears from evaporating off the eye.  When the oily secretion is clogged inside the gland, the tear film is missing proper components and thus dries up very quickly, causing dry eye symptoms.  If the glands are actually clogged and capped, their yellow dome-like contents may be visible along your lids when you look in the mirror.  
Clogged Meibomian Glands: also called impacted or inspissated glands, or posterior blepharitis
CAUSES: Meiboiman gland dysfunction or blepharitis (inflammation along the eyelids) can be caused by dry skin or crusting along the lashline, poor gland secretion (typical with rosacea), staph bacteria (that normally is on our skin but can sometimes flare up), or hormone changes that affect the make-up of the glands and their secretions.
BLEPHARITIS: Scaly, crusty debris called "collarettes" hook onto the eyelashes, causing irritation, inflammation, a spike in staph bacteria count, and clogged meibomian glands!  You wouldn't be able to see it in the mirror, so make sure when you clean your lids, you massage or gently rub along the lashes to get rid of this debris!
TREATMENTS:
  • Warm compresses (typically with a warm washcloth) for 2-5 minutes with gentle massage along the lid and lash line
  • eyelid cleansers like: Ocusoft Foaming Eyelid Cleanser, or Sterilid lid scrubs
  • Pulsed treatment with prescription drops like Azasite or Besivance to improve gland secretion (I typically dose twice daily for 2 weeks and then once daily for 2 weeks to see improvements)
  • Oral Doxycycline (especially effective with rosacea or acne component).  I typically dose 20 mg of Doxy Hyclate twice daily for 2 weeks, then once daily for two weeks.  50 mg generic doxy with the same dosage is another common prescription.  Note: Doxy can cause rashes and severe sunburns!
  • For severe disease some doctors are using new techniques like meibomian gland probing or the Lipiflow device
OCUSOFT FOAMING LID CLEANSER: I love this stuff and prescribe it quite frequently!  Much better  than the old baby shampoo treatment 
OTHER THINGS TO KNOW: 
  • Your doctor may measure something called the "Tear Break Up Time" when discussing dryness.  Remember, poor gland secretion causes the tears to evaporate quickly.  If your tears are evaporating off the surface of your eye (or "breaking up") before 10 seconds, then you have clinically significant dry eye.
  • Your doctor may apply pressure to your eyelids to see if your meibomian glands are properly secreting.  The gland should secrete every time you blink, so there should be a noticeable, clear secretion when the doctor presses against your lids.  With MGD, the secretion may be a thick, white color like toothpaste.  Sometimes the gland is so clogged, no secretion at all comes out! If that is the case, your glands may be sclerosed closed, typically causing very severe dryness
  • If you have meibomian gland dysfunction, you may have a lot of depositing and haziness with your contact lenses.  Newer, more oxygen permeable contact lenses are made with a material called Silicone Hydrogel that in most patients improves comfort, in addition to being healthier for the eye. Biofinity and Air Optix Aqua are two examples of lenses in this category.  Silicone hydrogel is good for dryness in that it is hydrophobic, so should theoretically draw less water from the eye.  However, this also means that it attracts lipids, so clogged gland secretions stick to the material like glue.  If you are having these issues, you may have to be refit into an older hydrogel material like Proclear for comfort.  Dailies are a great solution because the lenses won't have enough time to deposit before you throw them away!

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