Meibomian gland dysfunction is a widespread contributor to dry eye syndrome. It is alternatively called MGD, meibomitis, and posterior blepharitis. MGD is a complex condition, but it generally involves swelling in the meibomian glands of the eyelid, which produce the lipids (meibome) that comprise the outer layer of the tear film. The infection may be caused by a clog on the gland outlet at the eyelid margin.
The clog, in turn, may be caused by an eyelid enlargement from allergies or anterior blepharitis (in the front of the eyelid). MGD may also develop from hormonal changes, or dietary customs that affect the thickness of the lipids. Sometimes, the extrusions may seem deeply creamy and viscous, or even toothpaste-like; at other times, a compact fatty ball may coagulate at the entrance, sealing it. Another variation of the dysfunction may be through heavy production of lipids inflaming the eyes, although no blockage of the glands occurs.
The consequence is that because of the dysfunction, the glands extrude low-quality lipids. There may be an excess of or a lack of oil; the oil may be too viscous or too light. The consequence is that there is little stability in the tear film and drying out happens at abnormal rates.
Symptoms and Associated Conditions
The symptoms of the disease ordinarily look like those observed with dry eye in general: burning sensation in the eye, grittiness, foreign body sensation, heightened sensitivity to light, and crusting along the lid margins. The lid margins appear swollen and inflamed and the inner rim of the eyelid may be dented because of scarring.
Meibomitis ordinarily arises together with inadequacy of aqueous tears. When this happens, chances are you will have particularly severe dry eye symptoms. Approximately 60 per cent of Sjögren’s syndrome patients (who have aqueous tear insufficiency) have been found to also have MGD. Other skin disorders like rosacea and seborrheic dermatitis – which frequently inflict blepharitis – are also linked with meibomian gland dysfunction. These intertwined diseases should also be addressed during the treatment of meibomian gland dysfunction.
The possibility of developing MGD appears to increase with age. It may be that the meibomian glands progressively wear down in their functioning, or that age-related alterations in the eyelids may contribute to impaired blink mechanisms. What has been noticed is that normal eyelids in seniors show many of the changes in structure and form observed in meibomitis.
MGD is also linked with long-term contact lens use. Contact lenses speed up the tear evaporation rate. This can lead to contact lens intolerance and make more severe the condition in people whose tear films are already damaged to begin with. Similarly, MGD is also generally noted in patients with giant papillary conjunctivitis (GPC) and chalazion (plural, chalazia; a lump that remains after a sty on the eyelid heals).
MGD, being a rather complex disease, has many possible causes. In any person, the condition may start from one or more of these causes. Your physician will have to keep these in mind as the treatment program proceeds.
The first priority in treatment is to reduce inflammation on the eye surface, in order to drain off the damage from bacterial activity on the eyelid rim, enhance lipid function, and provide relief from the accompanying dry eye symptoms.
Topical steroids can be recommended to manage inflammation, although this is not normally resorted to to avoid the high risk of side effects. But more recent formulations, such as loteprednol, do not carry such risk and are reasonably effective at bringing down inflammation. Specially formulated topical cyclosporine, such as cyclosporine emulsion in a castor oil base, has also been tried successfully to minimise eye surface inflammation.
Essential fatty acids, particularly omega-3 fatty acids, have been mentioned in many informal accounts with the capacity to decrease dry eye symptoms, probably because of their well-established anti-inflammatory properties. Their anti-inflammatory action has also been noted to benefit meibomian gland disease.
Lid scrubs can be quite helpful. Cleaning the eyelid margin helps dislodge bacteria and their toxins, as well as clears meibomian gland ducts. Overzealous cleansing can cause irritation, however, and should be avoided. Punctal plugs, artificial tears (without preservatives), and tear stimulants also deliver relief.