Müller Muscle and Ptosis Surgery

Müller muscle plays an important role in eyelid elevation and is one of the structures surgeons consider when planning ptosis surgery. While the levator muscle is the primary muscle responsible for opening the upper eyelid, the Müller muscle provides additional lifting support and helps maintain eyelid position.

In Korean eye plastic surgery, understanding the function of the Müller muscle allows surgeons to choose the most suitable ptosis correction technique based on each patient’s eyelid anatomy, degree of drooping, and muscle function.

What Is the Müller Muscle?

The Müller muscle is a small involuntary muscle located beneath the upper eyelid’s levator muscle.

Its main functions include:

• Providing additional upper eyelid elevation
• Helping maintain eyelid height
• Supporting consistent eyelid position
• Contributing to eye openness

Unlike the levator muscle, which is controlled voluntarily when opening the eyes, the Müller muscle is activated through the sympathetic nervous system.

How Does the Müller Muscle Affect Ptosis?

Ptosis occurs when the upper eyelid droops lower than desired and covers part of the eye.

While ptosis can result from several causes, including levator muscle weakness, the Müller muscle may also influence eyelid height.

Reduced Müller muscle function may contribute to:

• Mild eyelid drooping
• Uneven eyelid position
• Reduced eye exposure
• A tired-looking appearance

A surgeon evaluates both the levator muscle and Müller muscle before selecting a treatment approach.

Müller Muscle-Conjunctival Resection (MMCR)

Müller muscle-conjunctival resection is a ptosis correction technique that targets the Müller muscle from the inner surface of the eyelid.

During the procedure, the surgeon may:

• Remove or shorten a portion of the Müller muscle
• Adjust the supporting eyelid tissue
• Improve upper eyelid elevation

Because the incision is made inside the eyelid, there is typically no visible external scar.

Who Is a Good Candidate for Müller Muscle Ptosis Surgery?

Müller muscle-based ptosis surgery may be suitable for patients with:

• Mild to moderate ptosis
• Good levator muscle function
• Positive response to Müller muscle testing
• Relatively healthy eyelid tissue

Patients with severe ptosis or significant levator muscle weakness may require different techniques.

Combining Müller Muscle Surgery with Double Eyelid Surgery

Some patients undergo Müller muscle ptosis correction together with double eyelid surgery.

This combination may help improve:

• Eyelid opening
• Crease definition
• Eye symmetry
• Overall eye balance

However, creating a double eyelid crease without addressing underlying ptosis may not fully improve a heavy or sleepy eye appearance.

How Surgeons Evaluate Müller Muscle Function

Before recommending Müller muscle surgery, surgeons may perform detailed evaluations, including:

• Eyelid height measurement
• Levator muscle function testing
• Symmetry assessment
• Eyelid opening evaluation
• Response testing for Müller muscle function

This helps determine whether Müller muscle adjustment is likely to provide improvement.

Recovery After Müller Muscle Ptosis Surgery

Recovery depends on whether the procedure is performed alone or combined with other eyelid surgeries.

First Week

Patients may experience:

• Swelling
• Bruising
• Eyelid tightness
• Temporary uneven eyelid height

The eyelids may appear slightly higher during early healing.

Weeks 2–6

During this period:

• Swelling gradually decreases
• Eyelid position becomes more stable
• Eye appearance begins to look more natural

Small differences between both eyes may continue improving.

Months 3–6

Final results become clearer as:

• Tissues settle
• Eyelid movement becomes smoother
• Scars and swelling continue to mature

Possible Concerns After Müller Muscle Ptosis Surgery

As with other ptosis procedures, patients may experience temporary concerns such as:

• Dry eyes
• Difficulty closing the eyes
• Eyelid asymmetry during healing
• Overcorrection or undercorrection

Regular follow-up allows surgeons to monitor recovery and address concerns if needed.

Revision After Müller Muscle Ptosis Surgery

Revision may be considered when patients experience:

• Persistent eyelid drooping
• Excessive eyelid elevation
• Uneven eye height
• Functional discomfort

Revision planning requires careful evaluation of previous muscle adjustment and remaining eyelid function.

Final thoughts

The Müller muscle plays an important supporting role in eyelid elevation and ptosis correction. Müller muscle-based surgery can be an effective option for selected patients with mild to moderate eyelid drooping and good eyelid muscle function. By carefully evaluating the Müller muscle, levator muscle, and overall eyelid anatomy, Korean eye surgeons can create customized ptosis treatments that improve both eyelid function and natural eye appearance.