Medical Glossary

Below you will find explanations of medical terms frequently encountered in oculoplastic surgery, eyelid disorders, and periocular anatomy. Each term is defined as used in clinical practice.

Ankyloblepharon

Fusion of the upper and lower eyelids. May be congenital or develop after trauma or burns.

Blepharoplasty

Surgical correction of excess skin, muscle, or fat tissue in the upper or lower eyelids. Performed for aesthetic or functional purposes. → Blepharoplasty treatment

Brow Lift

Surgical elevation of low-positioned eyebrows. May be combined with upper eyelid surgery when appropriate. → Brow lift treatment

Canthoplasty / Canthopexy

Surgical tightening or repositioning of the outer corner of the eyelid (lateral canthus). Canthoplasty involves cutting and re-suturing the tendon; canthopexy suspends it without cutting.

Conjunctiva

The thin, transparent mucous membrane that covers the front surface of the eye and the inner surface of the eyelids.

Cornea

The transparent front layer of the eye. One of the primary optical structures the eyelids are responsible for protecting.

Dacryocystorhinostomy (DCR)

Surgical procedure to correct a blocked tear duct by creating a new drainage pathway into the nose. Can be performed endoscopically or externally. → DCR surgery

Dermatochalasis

Age- or genetic-related excess and laxity of the upper eyelid skin. Differs from ptosis in that the lid margin remains in normal position. → Dermatochalasis treatment

Ectropion

Outward turning of the eyelid (usually lower). Leads to tearing, dryness, and increased infection risk. → Ectropion treatment

Entropion

Inward turning of the eyelid (usually lower). Causes lashes to rub against the eye surface, potentially damaging the cornea. → Entropion treatment

Epiblepharon

A congenital condition where lower eyelid skin causes the lashes to be directed toward the eye. More common in children of Asian origin.

FEBO

Fellow of the European Board of Ophthalmology. An internationally recognized ophthalmology board certification awarded by the European Board of Ophthalmology.

Graves Orbitopathy (Thyroid Eye Disease)

An autoimmune condition associated with thyroid gland disease that can cause eyelid retraction, forward protrusion of the eye (proptosis), and restricted eye movements. → Thyroid eyelid disorders

Hordeolum (Stye)

Acute infection of sebaceous or sweat glands at the eyelid margin. Appears as a painful, red, raised lesion.

Lagophthalmos

Inability of the eyelids to close completely. May develop after facial paralysis, trauma, or oculoplastic surgery; carries risk of corneal drying.

Levator Palpebrae Superioris

The main muscle that elevates the upper eyelid. Weakness of this muscle or its tendon causes ptosis.

MRD1 / MRD2

Margin Reflex Distance. MRD1 is the distance between the upper lid margin and the corneal light reflex (normal 4-5 mm); MRD2 is the distance between the lower lid margin and the corneal light reflex. Used in ptosis grading.

Oculoplasty

A subspecialty of ophthalmology dealing with surgical treatment of the eyelids, periocular soft tissues, lacrimal system, and orbit. → About oculoplasty

Orbit

The bony cavity housing the eyeball and surrounding structures (muscles, nerves, vessels, fat).

Orbital Septum

The fibrous membrane forming the anterior boundary of the orbit, holding orbital fat behind the eyelids. An important anatomical landmark in blepharoplasty.

Proptosis (Exophthalmos)

Forward displacement of the eyeball beyond the normal orbital position. Most commonly associated with Graves orbitopathy.

Ptosis

Drooping of the upper eyelid below its normal position. Can be congenital or acquired (aponeurotic, neurogenic, mechanical). → Ptosis treatment

Punctum

The small opening at the inner margin of each eyelid that initiates tear drainage. Each lid has one (upper and lower).

Retraction (Eyelid Retraction)

When the eyelid sits higher (upper) or lower (lower) than normal. A characteristic finding in Graves orbitopathy.

Schirmer Test

A clinical test measuring tear production. A small filter strip is placed in the lower lid to assess wetting distance.

Snap-back Test

A clinical test assessing lower eyelid tone. The lid is pulled down and released; it normally returns immediately. Delayed return indicates laxity.

Tarsal Plate

The dense connective-tissue structure giving the eyelids their shape and firmness. Larger in the upper than the lower lid.

Trichiasis

Misdirection of eyelashes toward the eye. Can cause corneal irritation and damage. → Trichiasis treatment

Xanthelasma

Yellowish cholesterol-rich plaques that appear around the eyelids. Typically seen symmetrically at the inner canthus. → Xanthelasma treatment