Droopy eyelids (ptosis): causes and correction

What is ptosis?

Ptosis is a condition in which the upper eyelid sits lower than normal and covers part of the iris and pupil. A drooping eyelid or an uneven double eyelid crease can noticeably change your appearance, and precise correction is said to require a clear understanding of the structures that determine eyelid height, contour, and the amount of eyelid visible below the crease ^[1].

There are many causes. Congenital ptosis is present from birth because the muscle that opens the eye (levator muscle) did not develop properly; in children it can also result from muscle, nerve, or mechanical causes, or from injury ^[2]. Ptosis can also develop in adulthood (acquired ptosis), so identifying the cause comes first in any correction.

Ptosis in children and visual development

Congenital ptosis appears within the first year of life. It can occur on its own or as part of various eye conditions or whole-body (systemic) conditions ^[3]. Because congenital ptosis can interfere with visual development and function, correcting it at the right time is described as important ^[2].

That said, not every child with congenital ptosis needs surgery. The research concludes that early surgical correction may help children who have developed a lazy eye (amblyopia) because of a difference in focusing between the eyes caused by astigmatism, or because the eyelid blocks visual input ^[3]. Whether and when to operate is decided after an examination that includes an eye exam.

Types of corrective surgery

There are several operations for correcting ptosis, each with its own indications, advantages, and drawbacks, so a tailored approach is needed for each patient ^[2]. The operation is chosen based on patient factors such as how much the eyelid droops and how well the levator muscle works, as well as the surgeon's preference and circumstances ^[3]. The methods most often studied are the following ^{[2, 4]}.

• Frontalis suspension: connecting the eyelid to the forehead muscle so the forehead can lift the eyelid
• Levator resection and advancement: shortening or pulling forward the levator muscle and securing it
• Müller's muscle conjunctival resection: removing part of Müller's muscle and the conjunctiva from the inside of the eyelid
• Aponeurotic surgery: reattaching the tendon sheet (aponeurosis) of the levator muscle

Research on how much each method corrects

A 2016 review gathered 28 studies and compared the change in MRD1 (marginal reflex distance 1) by surgical method ^[4]. MRD1 is the distance from the light reflex on the cornea to the edge of the upper eyelid, and it is used as a measure of eyelid height. The studies analyzed included 8 on aponeurotic surgery, 10 on Müller's muscle resection, 4 on levator resection, and 6 on frontalis suspension ^[4].

The overall average improvement was 2.15mm: 2.4mm for frontalis suspension, 2.3mm for aponeurotic surgery, 2.0mm for Müller's muscle resection, and 1.8mm for levator resection ^[4]. Except for the difference between frontalis suspension and aponeurotic surgery, the differences between groups were statistically significant ^[4].

However, these figures are hard to read as a ranking of the methods. Eyelid height and age before surgery differed between groups: the frontalis suspension group had the lowest eyelid position before surgery, and the levator resection group was the youngest, with an average age of 18.9 years ^[4]. The average follow-up was 8.1 months, and in the three groups other than aponeurotic surgery the improvement shrank over time ^[4]. The authors attributed the slight increase in improvement in the aponeurotic surgery group to relatively well-preserved levator function and a short follow-up period (an average of 5.4 months) ^[4].

Frontalis suspension when the levator muscle is weak

For severe ptosis with weak levator function, frontalis suspension is described as the standard operation, using either the patient's own tissue or a synthetic material to lift the eyelid ^[6]. One report found that in children, the most common form is congenital ptosis that affects only one side and comes with weak levator function, and that frontalis suspension is the most frequently performed operation ^[5].

The same review cited research showing that stitching the sling material directly to the tarsal plate is important for improving the success rate, and concluded that the shape of the sling design did not affect the final result ^[5]. As for materials, the patient's own thigh tissue (autologous fascia lata) was rated an excellent material with the fewest complications and was presented as the material to consider first for long-term correction ^[5]. When only one eye droops, the review favored operating on that side alone ^[5].

One report has described a new technique that threads silicone material through tiny stab incisions, but it is a case report of a single 83-year-old patient observed for 2 months, so there is not enough evidence to judge its effectiveness and safety ^[6].

Recurrence, complications, and what to ask during your consultation

Surgery for congenital ptosis is challenging, and it is not unusual to need two or more operations because the droop returns ^[3]. A review of ptosis in children stresses that careful planning before surgery and careful judgment during surgery are needed to get good results and reduce complications ^[2]. Because the amount of correction tended to decrease over time with several of the methods ^[4], it is a good idea to keep having your progress checked after surgery.

• The cause of the droop (congenital, acquired, or a muscle or nerve problem, for example)
• How well your levator muscle works and how much the eyelid droops
• For children, whether there are problems with visual development such as a lazy eye
• The recommended operation, why it is recommended, and its expected pros and cons
• The chance of recurrence and what happens if revision surgery is needed