Meibomian gland dropout is the loss of specialized glands in the eyelids that produce oil for the tear film, which can lead to evaporative dry eye. “Dropout” refers to the disappearance of glands, while atrophy describes glands that are present but non-functional. This loss can occur in sections or along a gland’s entire length and is a sign of meibomian gland dysfunction (MGD).
The Role of Meibomian Glands
Meibomian glands are sebaceous glands located along the edges of the eyelids near the eyelashes, with approximately 25 to 40 in the upper lid and 20 to 30 in the lower. Each gland produces an oily substance called meibum, which is secreted through a duct that opens onto the lid margin.
The primary function of meibum is to form the outermost layer of the eye’s tear film, which also includes a middle aqueous (watery) layer and an inner mucus layer. This oily layer prevents the rapid evaporation of the watery component of tears. Much like a layer of oil on water, meibum stabilizes the tear film, keeping the eye’s surface lubricated and clear. The act of blinking helps spread this oil across the ocular surface.
Causes and Contributing Factors
The loss of meibomian glands results from the chronic blockage of their terminal ducts. This obstruction can be caused by hyperkeratinization, a process where cells produce excess keratin, or by meibum that becomes too thick to flow properly. Over time, this blockage leads to pressure buildup, atrophy from disuse, and the eventual dropout of the glands.
Several factors can increase the risk of developing this condition. These include:
- Advancing age, as gland function and meibum composition change over time, particularly after 40.
- Hormonal changes, such as a deficiency in androgens.
- Medical conditions like acne rosacea, psoriasis, Sjogren’s syndrome, and rheumatoid arthritis.
- Prolonged digital screen use, which leads to a reduced blink rate.
- Contact lens wear, which is associated with changes in meibomian gland structure.
- Improperly removed eye makeup, which can physically block gland openings.
Associated Symptoms and Diagnosis
Common symptoms include a gritty or sandy feeling in the eyes, burning, itching, and soreness. Vision may become blurry or fluctuate, and some people experience increased light sensitivity. Paradoxically, watery eyes can also be a symptom, as an unstable tear film can trigger reflex tears that lack the proper composition to lubricate the eye.
An eye care professional diagnoses the condition through a comprehensive exam. This includes examining the eyelids with a slit lamp and applying gentle pressure to assess the quality of expressed meibum. A tear breakup time (TBUT) test may also be performed, which uses dye to measure how long the tear film remains stable after a blink.
The most definitive diagnostic method is meibography. This imaging technique uses infrared light to capture high-resolution images of the meibomian glands. The images allow a clinician to directly see the gland structure, identifying areas of shortening, distortion, or complete dropout. This visual evidence helps confirm the diagnosis and assess the condition’s severity.
Management and Treatment Approaches
Lost meibomian glands cannot be regrown, but treatments can improve the function of remaining glands and manage symptoms. At-home care involves the regular application of warm compresses to the eyelids to help melt hardened oils. This is followed by gentle eyelid massage to help express the meibum, and consistent lid hygiene with specialized cleansers to remove debris.
Increasing omega-3 fatty acid intake through fish or flaxseed oil may reduce inflammation and improve meibum quality. Prescription medications may also be used. These can include topical antibiotics like azithromycin or oral antibiotics like doxycycline, which are prescribed for their anti-inflammatory properties rather than for fighting infection.
For more significant dysfunction, several in-office procedures are available.
Thermal Pulsation Systems
Systems like LipiFlow, iLux, and TearCare apply controlled heat and pressure to the eyelids. This process liquefies and removes blockages from the glands. A single treatment, such as a 12-minute LipiFlow session, can improve gland secretions for an extended period.
Intense Pulsed Light (IPL)
Originally used in dermatology, IPL uses specific wavelengths of light to reduce inflammation along the eyelid margin. This helps to unclog glands and stimulate healthier function. IPL often requires multiple sessions to achieve and maintain results.