Ptosis (pronounced TOE-sis) is an abnormally low position of the upper eyelid. When the levator muscle — the primary eyelid elevator — or Müller’s muscle weakens, stretches, or detaches from the eyelid, the lid drops in front of the pupil. Ptosis may affect one eye or both and ranges from barely noticeable to severe enough to obstruct vision entirely.
Interactive: The Eyelid and Your Vision — Side by Side
Ptosis is not only a change in appearance — it directly removes vision. Use the simulator below: as you drag the slider, the upper eyelid on the left droops from its normal position into severe ptosis, while the panel on the right shows what the patient actually sees as the lid progressively blocks the upper (superior) field of vision. This superior field loss is what insurers measure with formal visual-field testing when determining whether ptosis repair is functional (covered) rather than cosmetic.
What insurers ask for (functional coverage)
Visual-field test performed untaped and with the lid/skin taped up (showing improvement)
Margin reflex distance 1 (MRD-1) measurement
Frontal and side photographs documenting the lid or skin position
Criteria vary by plan — confirm specifics with Dr. Caster's office.
Ptosis SimulatorEyelid Position & Visual Field
The Eyelid
What the Patient Sees
What the Patient Sees
NormalSevere ptosis
Drag the slider — as the eyelid droops, watch how much of the upper visual field disappears.
Ptosis is also called blepharoptosis
It differs from dermatochalasis (excess upper eyelid skin) — though both conditions frequently coexist
A drooping lid that crosses the pupil reduces the superior visual field, causes eyebrow strain and headaches, and in children can lead to amblyopia (“lazy eye”)
For a detailed guide to levator anatomy, Müller’s muscle, and the tarsal plate, see our dedicated Anatomy Overview page.
Types & Causes of Ptosis
Ptosis is grouped by cause — age-related (aponeurotic), congenital, and neurologic. Recognizing the type guides both the work-up and the operation.
Explore Ptosis
Ptosis ranges from age-related drooping to conditions present from birth, each evaluated and treated differently. Explore each in depth:
Ptosis is more than a cosmetic concern — because the lid sits in the line of sight, it steadily narrows the field of view. Common signs include:
A visibly lower eyelid on one or both sides, often described as looking tired or sleepy
Difficulty reading or a sense that the upper part of your vision is cut off
Chronically raised eyebrows and forehead ache from the frontalis muscle straining to lift the lids
Tipping the head back or lifting the lid with a finger to see
In children, a persistently drooping lid that can threaten visual development
Types & Causes in Depth
Identifying why the lid droops determines the correct operation, so surgeons classify ptosis by mechanism:
Aponeurotic (age-related): The most common adult form. The levator tendon stretches or detaches from the tarsal plate with age, contact-lens wear, or after eye surgery. Levator strength is usually preserved. See Acquired Ptosis.
Congenital: Present from birth, usually from a poorly developed levator muscle. Because a lid covering the pupil can cause amblyopia (“lazy eye”) in roughly 30% of cases, early evaluation is essential. See Congenital Ptosis.
Neurogenic: A nerve-signal problem — third-nerve palsy, Horner’s syndrome (ptosis with a small pupil), or myasthenia gravis (fatigable, variable ptosis).
Myogenic: The muscle itself is diseased, as in chronic progressive external ophthalmoplegia.
Mechanical & synkinetic: A lid weighed down by mass or scarring, or the Marcus Gunn jaw-wink, where the lid lifts with jaw movement.
Ptosis (a low lid margin) is distinct from dermatochalasis (excess upper-lid skin), though the two frequently coexist — see Ptosis vs. Blepharoplasty.
How Ptosis Is Diagnosed
A focused eyelid exam measures a few key numbers that drive both the diagnosis and the surgical plan:
Margin reflex distance (MRD-1): the gap from the central corneal light reflex to the upper-lid margin — normally about 4–5 mm. Ptosis is generally present when MRD-1 is 2 mm or less.
Levator function: upper-lid travel from down- to up-gaze, graded good (≥10 mm), fair (5–9 mm), or poor (≤4 mm). This single measurement largely dictates which operation is chosen.
Phenylephrine (Neo-Synephrine) test: drops that stimulate Müller’s muscle predict the response to a Müller’s-muscle conjunctival resection.
Treatment is matched to the cause and to levator function. The main options:
Levator advancement / resection: the workhorse repair when levator function is fair-to-good — the stretched muscle is reattached and tightened.
Müller’s-muscle conjunctival resection (MMCR): an internal, no-external-scar option for mild ptosis with a positive phenylephrine test.
Frontalis sling: for poor levator function (including many congenital cases), the lid is connected to the forehead muscle so the brow does the lifting.
Oxymetazoline 0.1% (Upneeq) drops: a non-surgical daily eyedrop that lifts the lid a millimeter or two by stimulating Müller’s muscle — useful for mild ptosis or patients not ready for surgery.
Ptosis repair is often functional rather than cosmetic: when a formal visual-field test shows the lid obstructs your superior vision, the repair is frequently covered by insurance with prior authorization and photographs. If ptosis repair is combined with a cosmetic blepharoplasty, the skin (blepharoplasty) portion is billed separately as cosmetic. Ask the office for an itemized estimate and to verify coverage before surgery. The measurements insurers require, self-pay prices, and combined-billing rules are covered in Ptosis Surgery Cost & Insurance, part of our Eyelid Surgery Cost & Insurance guide.
Choosing an Oculoplastic Surgeon
Millimeters decide the result in ptosis surgery, and lid height must be balanced against the fellow eye (Hering’s law can unmask ptosis on the other side after repair). This is best handled by an oculoplastic surgeon with combined ophthalmology and eyelid-plastic training; ASOPRS fellowship-trained surgeons perform these repairs routinely. Find one through our surgeon directory.
Recovery & Results
Ptosis repair is typically an outpatient procedure under local anesthesia with light sedation. Bruising and swelling settle over 1–3 weeks, and because swelling shifts lid height, the final position is judged at a few weeks to a few months. Most repairs are durable for years; a minority need a minor height adjustment, which is a normal and expected part of fine-tuning millimeter-level symmetry.
Matching the Operation to Levator Function
The single measurement that drives the surgical plan is levator function — how far the upper lid travels from down-gaze to up-gaze. It sorts patients into three groups, each with a preferred repair:
Good function (≥ 10 mm): the muscle works well and only needs tightening — a levator advancement, or an internal, no-external-scar Müller’s-muscle conjunctival resection (MMCR) when a phenylephrine test is positive.
Fair function (5–9 mm): usually a levator advancement, with the amount of tightening titrated to the measured function.
Poor function (≤ 4 mm): the muscle cannot lift the lid reliably, so a frontalis sling connects the lid to the forehead muscle and the brow does the lifting — the standard choice for most severe congenital cases.
Two measurements refine it further: MRD-1 (light-reflex to upper-lid margin, normally about 4–5 mm; ptosis at 2 mm or less) sets how much lift is needed, and Hering’s law warns that repairing one lid can unmask ptosis on the other — which an experienced surgeon accounts for before operating rather than discovering afterward. See the full work-up on our Ptosis Evaluation page and the operative detail on Ptosis Treatment.
Ptosis (TOE-sis) is drooping of the upper eyelid caused by weakness or dysfunction of the levator muscle — the muscle responsible for lifting the upper eyelid. It can affect one or both eyes and may be present from birth (congenital) or develop over time (acquired).
What is the difference between ptosis and blepharoplasty?
Ptosis is caused by levator muscle weakness and requires surgical repair of the muscle itself. Blepharoplasty addresses excess skin overlying the eyelid. Both conditions can cause drooping or hooding, and they often occur together. Only an oculoplastic surgeon can reliably distinguish them and perform the correct procedure.
How is ptosis repaired surgically?
The most common technique is levator advancement — tightening the levator aponeurosis through an external incision in the eyelid crease. If levator function is poor (as in severe congenital ptosis), a frontalis sling procedure connects the eyelid to the brow muscle. Mild ptosis in patients who respond to phenylephrine drops can be corrected with a Müller's muscle-conjunctival resection (MMCR).
Is ptosis surgery covered by insurance?
Yes — ptosis repair is typically covered by health insurance when the drooping eyelid causes functional visual field obstruction, documented by a formal visual field test with the eyelid in its resting position.
What should I expect during a ptosis consultation?
During your consultation, Dr. Caster will perform a comprehensive eye examination, including measuring your eyelid height and assessing how well your levator muscle functions. You'll discuss your symptoms, review your medical history, and examine photographs to determine if you're a good candidate for surgery. The surgeon will explain the appropriate surgical technique for your specific condition and answer any questions about risks, recovery, and expected outcomes.
What are the potential risks and complications of ptosis surgery?
While ptosis repair is generally safe, potential complications include infection, bleeding, scarring, and asymmetry between the two eyelids. Some patients may experience temporary dry eyes, difficulty closing the eyelid completely, or under- or over-correction requiring revision surgery. These complications are uncommon, especially when performed by a fellowship-trained oculoplastic surgeon, and most resolve with appropriate care.
What is the recovery timeline after ptosis surgery?
Most patients can return to light activities within one to two weeks, though complete healing typically takes four to six weeks. During the first few days after surgery, you may experience swelling, bruising, and mild discomfort managed with prescribed medications and cold compresses. You'll have follow-up appointments to monitor healing, and Dr. Caster will provide specific instructions about activity restrictions, eye care, and when you can resume normal routines.
What causes a droopy eyelid (ptosis)?
The most common cause in adults is aponeurotic ptosis, where the levator tendon stretches or detaches with age, contact-lens wear, or after eye surgery. Other causes include congenital (present from birth), neurogenic (nerve problems such as Horner's syndrome, third-nerve palsy, or myasthenia gravis), and myogenic muscle disease.
Can ptosis be fixed without surgery?
Mild ptosis can be improved with oxymetazoline 0.1% (Upneeq) eyedrops, which stimulate Muller's muscle to lift the lid a millimeter or two. Drops are temporary and work best for mild cases; moderate to severe ptosis is corrected surgically.
Is ptosis repair covered by insurance?
Ptosis repair is often covered when it is functional -- when a formal visual-field test documents that the lid obstructs your superior vision. Photographs and prior authorization are usually required. If a cosmetic blepharoplasty is done at the same time, the skin portion is billed separately as cosmetic.
How is ptosis diagnosed?
An oculoplastic surgeon measures margin reflex distance (MRD-1, normally about 4-5 mm; ptosis at 2 mm or less) and levator function (good is 10 mm or more, poor is 4 mm or less), and may use a phenylephrine test and visual-field testing. These measurements determine which repair is appropriate.
