# Eyelid Malpositions: Ptosis, Entropion, and Ectropion

## Introduction

Eyelid malpositions are among the most common conditions encountered in oculoplastic practice. **Ptosis**, **entropion**, and **ectropion** each result from distinct anatomic and pathophysiologic mechanisms, and accurate diagnosis is essential for selecting the appropriate surgical correction. This lecture reviews the classification, evaluation, and surgical management of these three entities.

## Ptosis

### Definition and Classification

**Ptosis** (blepharoptosis) is an abnormally low upper eyelid position. Normal margin-reflex distance 1 (MRD1) is 4-5 mm. Classification by etiology:

**Aponeurotic** -- most common; involutional dehiscence or disinsertion of the levator aponeurosis. **Myogenic** -- myasthenia gravis, chronic progressive external ophthalmoplegia, myotonic dystrophy. **Neurogenic** -- cranial nerve III palsy, Horner syndrome. **Mechanical** -- lid mass, dermatochalasis, cicatricial changes. **Traumatic** -- post-surgical or post-injury levator damage.

### Clinical Evaluation

Measure **MRD1**, **MRD2**, **palpebral fissure height**, and **levator function** (normal >= 12 mm) Assess **phenylephrine test** for Muller muscle-conjunctival resection (MMCR) candidacy. Rule out pseudoptosis: dermatochalasis, contralateral lid retraction, hypotropia, enophthalmos. Check for **Hering dependence** by elevating the ptotic lid and observing the contralateral lid.

### Surgical Options

| Procedure | Indication | Levator Function | Key Notes |
|-----------|-----------|------------------|-----------|
| Levator advancement/resection | Moderate-severe ptosis | >= 5 mm | Most common surgical repair |
| Muller muscle-conjunctival resection (MMCR) | Mild ptosis | Good | Positive phenylephrine test required |
| Frontalis sling | Severe ptosis | < 4 mm | Congenital ptosis, CN III palsy |

**Levator advancement/resection** -- levator function >= 5 mm. **Muller muscle-conjunctival resection (MMCR)** -- mild ptosis with positive phenylephrine test. **Frontalis sling** -- levator function < 4 mm (e.g., congenital ptosis, CN III palsy)

![Clinical photograph showing measurement of MRD1 in a patient with involutional ptosis](/images/ophthalmology/ptosis-mrd1-measurement.jpg)

## Entropion

### Definition and Classification

**Entropion** is inward turning of the eyelid margin, causing lash-cornea contact and irritation.

**Involutional** -- most common; horizontal lid laxity, lower retractor disinsertion, overriding preseptal orbicularis. **Cicatricial** -- tarsal conjunctival scarring (trachoma, Stevens-Johnson syndrome, ocular cicatricial pemphigoid, chemical burns) **Congenital** -- rare; epiblepharon is more common in Asian children. **Spastic** -- acute orbicularis spasm secondary to ocular irritation.

### Surgical Management

**Involutional**: quickert sutures (temporary), lateral tarsal strip + lower retractor reinsertion + orbicularis repositioning. **Cicatricial**: posterior lamellar graft (mucous membrane, hard palate, amniotic membrane)

## Ectropion

### Definition and Classification

**Ectropion** is outward turning of the eyelid margin, leading to exposure, tearing, and conjunctival keratinization.

**Involutional** -- horizontal lid laxity, canthal tendon laxity. **Cicatricial** -- skin shortage from trauma, burns, prior surgery, actinic damage. **Paralytic** -- facial nerve (CN VII) palsy. **Mechanical** -- lid tumor, edema, orbital fat prolapse.

### Surgical Management

**Involutional**: lateral tarsal strip procedure, medial canthal tendon plication if medial ectropion present. **Cicatricial**: skin graft (full-thickness from upper lid or postauricular) or flap reconstruction. **Paralytic**: gold weight implant, lateral tarsorrhaphy, canthoplasty.

![Intraoperative photograph of lateral tarsal strip procedure for involutional ectropion](/images/ophthalmology/lateral-tarsal-strip-procedure.jpg)

## Complications of Untreated Eyelid Malpositions

Corneal abrasion, ulceration, and scarring (entropion) Chronic epiphora and conjunctival keratinization (ectropion) Exposure keratopathy and secondary infection. Amblyopia in pediatric congenital ptosis with visual axis occlusion.

![Slit-lamp photograph showing corneal pannus from chronic entropion with trichiasis](/images/ophthalmology/entropion-corneal-pannus.jpg)

## Key Clinical Pearls

Always check for Hering dependence before ptosis surgery to avoid unmasking contralateral ptosis. A positive phenylephrine test (>= 2 mm lid elevation) predicts good MMCR outcomes. Involutional entropion has three pathogenic components; address all three for durable repair. Cicatricial ectropion requires tissue replacement, not simply horizontal tightening. In paralytic ectropion, prioritize corneal protection while awaiting potential nerve recovery.

## References

1. Finsterer J. Ptosis: causes, presentation, and management. Aesthetic Plast Surg. 2003;27(3):193-204.
2. Vallabhanath P, Carter SR. Ectropion and entropion. Curr Opin Ophthalmol. 2000;11(5):345-351.
3. Nerad JA. Oculoplastic Surgery: The Requisites in Ophthalmology. Mosby; 2001.
4. American Academy of Ophthalmology. Orbit, Eyelids, and Lacrimal System. BCSC Section 7. 2023-2024.