#dryeyes #meibomiangland The eyelid's roles are to protect the eye from foreign bodies and injuries and to lubricate the surface of the eye. To lubricate the eye, the eyelid does 2 things: spread the tears on the surface of the eye by blinking and supply the oily layer of the tears via the secretion of the meibomian glands. Therefore, conditions affecting the eyelid structure, blink mechanism and function of the meibomian glands can play a role in dry eye disease. Let's take a closer look at these conditions.
Malposition or incomplete closure of the eyelids can leave the eye exposed. In aging eyes, the lids can become less taut and droopy. A very loose upper eyelid, as seen in floppy eyelid syndrome, can evert during sleep and cause ocular surface dryness. In thyroid eye disease, the eyes bulge and may inhibit eyelid closure. Incomplete eyelid closure, also called lagophthalmos, can also happen after cosmetic surgery/injection or from nerve damage arising from an injury, stroke, or Bell's palsy. In some people, lagophthalmos occurs during sleep, which leads to trouble staying asleep or exacerbated dry eye symptoms upon waking.
The amount of light emanating from the eyelid area between the lashes checks for incomplete eyelid closure Source: https://www.reviewofoptometry.com/article/night-moves
Infrequent and incomplete blinking lead to inadequate lubrication of the ocular surface. A decreased blink rate leads to less secretion of the meibomian glands, which is responsible for producing the oily layer of tears to prevent it from evaporating too fast. Decreased blink rate can be seen Parkinson's disease, conditions affecting corneal sensitivity (ex. post-LASIK), and more commonly, in computer vision syndrome. With incomplete blinking, as seen in visual fatigue, dry eye happens because the lids don't completely close during a blink and are unable to secrete the meibum off the glands along the eyelid margins.
Finally, let's focus on the meibomian glands.
The meibomian glands are oil producing glands that line the rim of the eyelids. They function to keep the tears on the surface of the eye longer by preventing evaporation. When they become clogged or have poor meibum quality, dry eye results. In fact, it is estimated that 80% of dry eye disease is caused by meibomian gland dysfunction. MGD is associated with age, androgen deficiency, systemic conditions such as Sjogren's syndrome and psoriasis, isotretinoin use, eyelid tattooing, and contact lens wear.
Normal meibum has the consistency of olive oil, while this eyelid has cloudy and thick secretion.
Because the eyelids play an important role in lubricating the eyes, it is imperative to include the management of these eyelid conditions in a dry eye regimen when an eyelid problem is identified. The next post will focus on products in the market that are designed to treat dry eye disease. If you find this helpful, leave us a comment and you'll be entered to win a Bruder mask!
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