Wednesday, May 15th, 2013
Medical problems of the eyelids are exceedingly common. They are exceptionally problematic because they disturb the proper function of the eyelid, which, in turn, can affect our vision, cause dry eye, or cause headache. They can be divided into those intrinsic to the eyelid and external problems that just happen to occur on or to the eyelid.
Intrinsic eyelid problems may be due to muscle abnormalities of the eyelid or laxness, scar, or malposition of the eyelid itself.
Perhaps the most common problem of the eyelid is droop or ptosis. This problem can be either extrinsic or intrinsic. Intrinsic droop of the upper eyelid is secondary to an abnormality of the muscle holding the eyelid up. This is complicated by the fact that there are actually three muscles that elevate the upper eyelid. The most common problem occurs when the levator, the voluntary lid elevator, stretches and becomes lax with time. We see this very commonly in people seeking cosmetic improvement of the eyelids. This muscle is easily accessed through a regular blepharoplasty incision and requires only a few stitches to imbricate it and elevate the eyelid to a normal position. Another common cause of droop seen at the time of cosmetic consultation is that from descent of the brow. Although it is most commonly due to gravitational pull on the brow, which causes the tissue from above the eyelid itself to descend into the eyelid, pushing the eyelid down, it can also occur from weakness of the frontalis muscle, the muscle that elevates the brow. Usually this is corrected with some type of brow lift procedure which pulls the tissues back into the brow where they belong and out of the eyelid, thus allowing the lid to assume its normal position. With the popularity of Botox®, we also occasionally see ptosis from weakening of the muscle s holding the eyelid up. Fortunately, this will resolve when the Botox® wears off.
The third muscle that controls eyelid position is Muller’s muscle. This is a muscle that is not voluntarily controlled but controlled by the sympathetic nervous system. It normally holds the eyelid in the correct position while you are awake, but it allows the eyelid to close when you become sleepy. Occasionally it also becomes stretched and fails to hold the eyelid in its normal and open position. When this occurs, this muscle is approached from the inside of the eyelid and shortened by removing a strip of conjunctiva and muscle from the back side of the lid.
Several problems occur to lower lid from either stretch of the lid itself or tightening of one of the layers of the lid or both. Of these, ectropion, eversion of the lower lid away from the globe, is most common. Mild forms can cause dry eye. More advanced forms cause chronic irritation of the lining of the eye and lid, with redness, swelling and occasionally even weeping. If left untreated, this can even cause blindness. This condition therefore needs to be treated early by simply taking out the excess lid length, adding skin to replace scar (usually from removal of a skin lesion), or both.
The opposite of an ectropion is an entropion where the lid turns inward. Frequently the most symptomatic part of this is what is known as trichiasis, or irritation of the eyeball from the eyelashes scraping against the globe or cornea. This condition is usually from some type of scarring of the internal layers of the eyelid following some type of surgery. Correction usually involves a graft of some description to release the scar.
Perhaps the most common problem in the eyelids is the presence of either malignant or nonmalignant lesions on the eyelid itself. Benign lesions generally require no treatment unless they are causing problems with function of the eyelid or are simply cosmetically undesirable. The one exception is verrucae, better known as warts. These lesions occur when a virus enters an otherwise benign lesion and begins growing. This can cause a very large, irritative lesion that can interfere with function of the lid, bleed, or become otherwise problematic. These are treated essentially like malignant lesions in order to make certain that all of the cells containing the virus are removed.
Premalignant and malignant lesions, however, such as actinic keratoses, basal cell epithelioma and squamous cell carcinoma, all do require treatment to prevent destruction of the eyelid. These are more easily treated on the loose upper eyelid skin. On the lower eyelid simple excision can cause ectropion or other functional abnormalities of the eyelid. Therefore, frequently a skin graft or flap which moves tissue from a looser area into the tighter lid may be necessary in order to prevent problems in lid function. This is one of the places where Moh’s surgery is exceptionally useful. Moh’s removes the lesion with exceptionally small margins and then makes certain, by microscopic examination, and further resection if necessary, that the margins are totally free. This allows removal of as minimal an amount of lid skin as possible. This procedure is done by a specially trained dermatologic surgeon. We generally then do the closure to assure that the eyelid continues to function properly.
Lesions near the lid margins are especially problematic because immediately under the skin at the margin is a thick, cartilaginous structure called the tarsus. Here the skin cannot simply be excised but requires grafting, a flap, or complete transection of the entire lid and tarsus in order to remove the lesion and close the defect.
In summary, there are multiple problems that can occur to the eyelids. Some of those problems have multiple causes. Therefore, when evaluating a problem, the underlying cause needs to be determined in order to select the most reasonable method for correcting the problem.