An eyelid refers to skin that folds over the eye to protect it. It is made up of two segments, the upper and lower eyelid.
Also Known As
The eyelid contains no subcutaneous fat making it the thinnest skin layer of the body. The main structural components of the eyelid are the tarsal plates which are made of dense connective tissue. The tarsal plates comprise of Meibomian glands (30 in the upper eyelid and 20 in the lower) and eyelash follicles. The upper eyelid contains approximately 100 lashes while the lower one has about 50. In the inner surface of the eyelids lies the squamous epithelium.
Eyelids help to distribute the tear film across the ocular surface. They help in draining the tears from the eyes and protecting ocular surfaces. Inside the eyelid are glands responsible for the secretion of substances that help lubricate the ocular surface. Eyelids serve cosmetic purposes too.
Associated symptoms & disorders
Some of the diseases associated with eyelids include:
- Bell’s palsy results in the eyelid not being able to close. It is a nerve problem that affects facial muscles leading to partial paralysis on one side of the face.
- Black eye results from a facial or head injury which causes bruising around the eye. Even though black eye may not be severe and may heal on its own, it can be a sign of hyphema. Hyphema is bleeding in the eye which can affect the cornea or intraocular pressure and lead to loss of vision.
- Cellulitis infection affects the skin, the eyes, face, arm and other areas. Preseptal cellulitis affects eyelid tissue while the more serious orbital cellulitis leads to the swelling of the eye socket. This may affect vision because the swollen eyelid may keep the eye from moving.
- Eyelid coloboma is a condition in which a baby is born without normal tissue in or around the eye.
- Conjunctivitis refers to the irritation of the conjunctiva caused by an infection or allergic reaction. The eye becomes red and swollen, sometimes with a sticky discharge.
- Dry eye describes a condition where the eye fails to produce enough tears or the right type of ears.
- Eyelid spasms cause the twitching or sudden closing of the eyelid.
- Graves' disease affects muscles and tissue surrounding the eye. The eye is pushed forward while the the upper and lower eyelids are retracted.
- Capillary hemangiomas interferes with the normal development of the eye. It affects the eyelids, inside the socket or the surface of the eye.
- Shingles is caused by herpes zoster resulting in painful, red blisters. A rash develops on the upper and lower eyelids that may lead to redness, burning and oozing on the inside of the eyelid.
- Kaposi sarcoma, a rare cancer with AIDS patients, causes purple-red swellings on the eyelids. It is harmless to the eye and can be treated.
- Mohs surgery is a procedure that removes cancer cells on the eyelids.
- Myasthenia gravis weakens muscles that control eyelid movement. The condition may lead to eyelid drooping.
- Ptosis is a condition where the upper eyelid droops over the eye which affects normal vision.
- In Sjögren's syndrome, the white blood cells in the body affect healthy tissue and organs leading to inflamed eyelid margins.
- Trachoma results from Chlamydia trachomatis which causes itching and irritation of the eyes and eyelids. If it is not treated, trachoma can lead to scarring inside the eyelid and eventual blindness.
- Other conditions affecting the eyelids include blepharitis (swollen eyelids caused by bacteria), chalazion and stye (swellings on the eyelid) and trichiasis (eyelashes growing inward).
Diagnosis of associated disorders
The eye care professional does a comprehensive eye examination to diagnose issues affecting the eyelid. He/she usually takes a medical history. The diagnosis depends on the specific condition. For instance, a physical examination and visual acuity test may diagnose black eye. For diseases that require an examination of the inside part of the eye, an imaging test or ophthalmoscopy is recommended. For cellulitis, a tissue culture or blood test may be conducted. A slit-lamp examination can help diagnose allergic conjunctivitis.
Treatment of associated disorders
Some conditions like Bell’s Palsy, viral conjunctivitis and black eye do not require treatment. They often resolve on their own. To manage symptoms of such conditions, a patient can use eye drops, anti allergy drugs, cool compresses, painkillers, etc.
Antibiotics can treat diseases associated with infections such as bacterial conjunctivitis. In HIV-related eye diseases, antiviral drugs can help with kaposi sarcoma.
Artificial tears or a gel plug inserted in the tear duct can treat dry eye. For Sjögren's syndrome, lubricating eye drops or ointments will keep the tears from drying out too quickly. Artificial tears, steroids, wearing sunglasses and using a cool compress can also help with dry eye.
Surgery is used in the treatment of conditions like hemangiomas. Laser surgery can also treat hemangiomas. Surgery can permanently close the tear ducts. Botulinum toxin injections or surgery can treat eyelid spasms. Wearing a patch for children and surgery for both children and adults can help treat ptosis. For trachoma, antibiotics and surgery to reposition the eyelids can be done.
Medicines to improve muscle strength and transmission between nerves and muscles may help with myasthenia. The doctor may also do a surgical procedure to remove the thymus gland.