One eyelid sitting noticeably lower than the other is called ptosis, and the fix depends entirely on why it’s happening. In most adults, the cause is a stretched or thinned connection between the muscle that lifts the eyelid and the eyelid itself. That connection weakens over time, letting the lid sag. Surgical repair is the only permanent fix, but temporary options exist, and some causes resolve on their own or with medical treatment.
Why One Eyelid Drops Lower
Your upper eyelid is lifted by a small muscle deep in the eye socket. That muscle connects to the eyelid through a thin sheet of tissue called the aponeurosis. When that tissue stretches, tears away, or thins out, the muscle can still contract but it can’t fully lift the lid. Histological studies of droopy eyelids show that about 71% of cases involve this tissue pulling away from the eyelid, while another 12% show the tissue has simply gotten thinner over time.
This age-related stretching is by far the most common reason adults develop a lower eyelid on one side. Years of rubbing your eyes, wearing contact lenses, or just blinking tens of thousands of times a day gradually loosens the connection. It typically shows up after age 50, though contact lens wearers sometimes notice it earlier.
Less common causes include nerve damage, muscle disease, injury, or prior eye surgery. In children, one eyelid may sit lower from birth if the lifting muscle didn’t develop properly.
Causes That Need Quick Attention
Most eyelid drooping is cosmetic or develops slowly over years. But a sudden drop in one eyelid, especially alongside other symptoms, can signal something more serious. Horner’s syndrome, which involves damage to a nerve pathway running from the brain to the face, produces a classic trio of signs: a drooping eyelid, a smaller pupil on the same side, and reduced sweating on that half of the face. This can result from a stroke, tumor, or injury to the neck or chest, and it requires prompt evaluation.
A condition called myasthenia gravis can also cause one eyelid to droop, often fluctuating throughout the day and worsening with fatigue. One simple screening tool involves placing an ice pack over the closed eyelid for two minutes. If the lid lifts noticeably afterward, it suggests the nerve-muscle connection is the problem rather than the tissue itself. This test has a sensitivity around 77% and specificity near 98%, making it a useful first clue before more detailed testing.
If your eyelid dropped suddenly, changes throughout the day, or appeared alongside double vision, pupil changes, or headaches, get it evaluated promptly rather than treating it as a cosmetic concern.
How Doctors Assess the Problem
An eye doctor or oculoplastic surgeon will measure how much of your eye the drooping lid covers. The key measurement is the distance from the center of your pupil to the edge of your upper eyelid. Normally, this distance is 4 to 5 millimeters. Anything less means the lid is sitting too low. They’ll also test how well your lifting muscle functions by holding your brow still and asking you to look up and down. The total distance the lid travels tells the surgeon how strong the muscle is, and that number largely determines which procedure will work best.
Surgical Options for a Permanent Fix
Surgery is the standard permanent correction. The specific technique depends on how well your eyelid muscle still works.
When the Muscle Works Well
If the muscle is strong but the connecting tissue has loosened, the surgeon reattaches or tightens that tissue. This is done through either the outside of the eyelid (an external approach) or the inside (an internal approach). External approaches are preferred when excess skin also needs to be removed at the same time, which is common in older adults. Internal approaches, where the surgeon works from the underside of the lid, allow a simple test beforehand: eye drops that temporarily stimulate the lid can predict where the eyelid will sit after surgery, giving a reliable preview of the result.
When the Muscle Is Very Weak
If the lifting muscle barely moves the lid (roughly 2 to 6 millimeters of movement or less), tightening the connection won’t help because the muscle itself can’t do the job. In these cases, surgeons use a sling procedure that connects the eyelid to the forehead muscle, so raising your eyebrows also lifts the lid. The sling can be made from tissue harvested from your own leg (a strip of the tough tissue that covers the thigh muscle), which is considered the most durable option. Silicone thread is an increasingly popular alternative because it avoids a second incision site and works for all ages, including young children who don’t have enough leg tissue to harvest.
What Recovery Looks Like
Bruising is normal for about two weeks after ptosis surgery. Swelling takes longer, often persisting for several weeks with minor puffiness still possible at the two-month mark. The eyelid typically doesn’t settle into its final position until two to three months after the procedure, so any remaining asymmetry during the first few weeks isn’t necessarily the permanent result.
During recovery, you’ll likely be told to avoid heavy lifting, bending over, and anything that increases pressure around your eyes. Most people return to desk work within a week, though the residual swelling can make things look worse before they look better.
Revision Rates and Realistic Expectations
Ptosis surgery has a meaningful chance of needing a touch-up. The overall revision rate across approaches is around 9%, though the numbers vary depending on technique. Internal approaches have a revision rate near 7%, while external approaches run closer to 10%, with some studies reporting rates as high as 18%. Revisions are usually minor adjustments to lid height or symmetry, not full repeat surgeries.
The reason revision rates are relatively high compared to other surgeries is that even a single millimeter of difference between eyelids is visible. Surgeons are working with extremely small tolerances, and swelling during the procedure can make it difficult to judge the final resting position perfectly. Complication rates beyond simple asymmetry (infection, scarring, difficulty closing the eye) are lower, in the 2 to 10% range.
Temporary and Non-Surgical Options
If surgery isn’t an option right now, or if you’re waiting for an underlying condition to be treated first, a few temporary approaches can help. Eyelid crutches are small wire supports attached to the frame of your glasses that physically prop the lid open. They work, but they prevent normal blinking and take some getting used to. Eyelid tape, sold over the counter, can lift a mildly drooping lid for cosmetic purposes during the day.
For ptosis caused by myasthenia gravis, medication that improves nerve-to-muscle signaling can lift the eyelid without surgery. In these cases, treating the underlying disease is the fix, not eyelid surgery.
There is no exercise, cream, or supplement that strengthens the levator muscle or reattaches loosened tissue. Products marketed for “eyelid tightening” may temporarily firm the skin, but they don’t address the structural problem underneath.