Ptosis surgery: how much do eyelids lift? Expectations and limitations from research

Ptosis surgery has been shown in research to raise the height of the eyelids and expand the upper visual field[1][2]In mild to moderate ptosis, the amount of lift was nearly the same whether the procedure was performed from the front or back of the eyelid[1]On the other hand, the amount of lift varies from person to person, and no research was found examining the effect on headaches or shoulder stiffness[3].

How much do eyelids lift with surgery?

In research, eyelid height is measured by the distance from the center of the iris to the eyelid margin (MRD1). In 33 people who underwent surgery to tighten Müller's muscle (one of the muscles that lifts the eyelid) from the back of the eyelid, this distance increased from an average of 1.20 mm to 3.35 mm[2].

In another study of people with good function of the eyelid-lifting muscles, the eyelids remained in the lifted position through 12 months after surgery[3]In people whose preoperative examination showed no effect on the opposite eye, surgery on one eye alone resulted in almost no change in the position of the eyelid of the opposite eye[2].

Is there a difference between the front-approach and back-approach methods?

In mild to moderate ptosis, there is no major difference. According to guidelines from the American Society of Plastic Surgeons, the anterior levator advancement technique (front approach) and Müller's muscle surgery achieved nearly the same visual field improvement (average MRD1 of 1.8 mm and 1.7 mm)[1].

For this reason, the guidelines recommend choosing the method based on the patient's preference and circumstances[1]In a study of 83 patients, 112 eyes, there was no difference in surgical outcomes based on the type of cause, such as age-related ptosis[4].

What changes if the ptosis is severe?

In severe ptosis, the front-approach method is reported to be superior in terms of long-term visual field improvement, with similar rates of complications[1]In people with very weak eyelid-lifting muscle strength, a method is used that borrows the strength of the forehead muscle to suspend the eyelid[5].

In congenital ptosis, anterior levator advancement is recommended in Japanese plastic surgery guidelines[6]If lowered eyebrows are partially responsible, improvement in visual field and appearance can be expected with eyebrow lift surgery or similar procedures[6].

What is still unknown from research?

There is variation in the amount of eyelid lift from person to person. In a study of 64 eyes stratified by response to an eye drop test (phenylephrine test), the lift at 12 months was 1.81 mm in those who responded and 2.50 mm in those who did not, showing a difference[3].

Additionally, there are few studies directly comparing similar methods, and some items in the guidelines are noted to have "very low" quality of evidence[1]No research was found in our search examining whether headaches or shoulder stiffness improve after surgery.

Effects on the eye itself are gradually becoming clearer. In a study of 7 eyes that had undergone corneal transplantation, some corneal distortion decreased after surgery[7].

How much can be expected from methods other than surgery?

Eye drops can temporarily lift the eyelid slightly. In a summary of five studies with oxymetazoline eye drops involving 458 people, MRD1 increased by an average of 1.40 mm[8].

However, there was large variation in results between studies[8]Rather than as a replacement for surgery, eye drops are best discussed as one option to consider before contemplating surgery.

How do you determine which method is right for you?

Three guidelines to consider when choosing a method are:

Whether the eyelid-lifting muscle has residual strength: if it does, you may choose either the front or back approach[1][5]

Severity of ptosis: in severe cases, the front approach offers long-term advantages[1]

Whether there is eyebrow descent or eyelid skin sagging: additional surgery may be combined[6][1]

What is checked during examination?

Which method is best cannot be decided from an article alone. This is because the strength of the eyelid-lifting muscle, eyebrow position, and skin sagging are assessed by actual measurement.

During examination, confirm how the eyelid height and muscle strength were measured, whether the approach will be from the front or back, and how over-correction or asymmetry will be managed if it occurs.