Lower blepharoplasty I — Assessment and decision algorithm

Anatomy I — The three lamellae

The lower eyelid is organised in three lamellae, dissected and repaired separately. The anterior lamella is skin and orbicularis muscle: eyelid skin is the thinnest in the body and tolerates no generous resection. The middle lamella is the orbital septum, a fibrous membrane arising from the arcus marginalisPeriosteal thickening at the orbital rim where the septum inserts that keeps fat inside the orbit; it is the structure that retracts on healing, and that retraction drives cicatricial ectropion. The posterior lamella comprises the retractors — capsulopalpebral fasciaFibrous extension of the inferior rectus inserting on the lower tarsal border, lowering the lid on downgaze and inferior tarsal muscle — together with tarsus and conjunctiva. This division explains why the transconjunctival approach is safer: it enters from behind, leaves the anterior lamella intact and creates no vertical scar pulling the lid margin down.

Anatomy II — Fat compartments and the inferior oblique

Behind the septum lie three fat compartments. The medial is the palest and most fibrous, and the one most often left residual unless deliberately sought. The central is the most accessible. The lateral is the yellowest and the most forgotten: a persistent lateral bulge is almost always its own. The anatomical fact governing dissection is that the inferior oblique muscle runs between the medial and central compartments; it must be identified before any traction, since injuring it produces vertical diplopiaDouble vision with one image above the other, typical of inferior oblique involvement on upgaze. Orbital fat is highly vascular and haemostasis must be performed under direct vision and anterior to the rim: cauterising a vessel that then retracts into the orbit is the mechanism of retrobulbar haematoma.

Anatomy III — Retaining ligaments, grooves and SOOF

At the orbital rim, the septum–periosteum junction and the retaining ligaments define the two grooves patients perceive as dark circles. Medially, the tear trough ligamentFibrous band joining the maxilla directly to the dermis, with no intervening muscle, along the medial third of the rim creates a fixed, tethered groove that skin tightening will not correct. Laterally, the orbital retaining ligament creates the tear valleyPalpebromalar groove: the depression continuing the tear trough laterally along the orbital rim. Below and lateral lies the SOOFSuborbicularis oculi fat: the fat pad beneath the orbicularis, over the malar bone, whose descent skeletonises the rim. The practical consequence is direct: while those ligaments remain intact, transposed fat will not cross the groove. Releasing the ligament is what blurs the hollow; the fat only fills what the release has opened.

Anatomy IV — The support system holding the lid up

The lid is held against the globe by a three-element tension system: the tarsus suspended between the medial canthal tendonMedial anchorage of the lid to the lacrimal bone and frontal process of the maxilla and the lateral canthal tendonLateral anchorage, inserting on Whitnall’s tubercle inside the lateral orbital rim, plus the tone of the pretarsal orbicularis, responsible for apposition to the globe. Breaking any of the three — a scar shortening the anterior lamella, pretarsal denervation, or uncorrected pre-existing tendon laxity — ends in lid malposition. This is why examining laxity is not a formality: it decides whether canthopexyRepositioning the lateral canthal tendon without dividing it, to tighten the lid or canthoplastyDivision and reinsertion of the lateral canthal tendon, usually with lid shortening via a tarsal strip must be added.

Focused examination: the four tests that change the indication

Assessment begins before looking at the bags. Snap-back test: pull the lid down and release without allowing a blink; a normal lid returns immediately, and if it is slow or needs a blink to reposition there is significant laxity. Distraction test: pull the lid away from the globe; separation beyond 6-8 mm indicates tendon laxity. Orbital vector: viewing the patient in profile, draw the line between the most prominent point of the globe and of the cheek; if the cheek sits behind, the vector is negative and the risk of postoperative lid retraction rises substantially. MRD2 (margin-reflex distance 2Distance between the corneal light reflex and the lower lid margin; normally 5 to 5.5 mm) documents the starting position and allows any later descent to be objectified. To all of this, always add assessment of dry eye and of Bell’s phenomenonReflex upward rotation of the globe on lid closure, protecting the cornea if some lagophthalmos remains.

Laxity tests → action

Examination of the four components

Is this dark circle surgical?

Choosing the approach and canthal support

Quick summary: finding → technique

1. Minimal skin laxity, no muscle hypertrophy, true herniation→Isolated retroseptal transconjunctival
2. Moderate skin laxity, malar bags, no muscle hypertrophy→Transconjunctival + subciliary skin pinch
3. Orbicularis hypertrophy demonstrated dynamically→Subciliary with skin and muscle resection + canthopexy
4. Associated ectropion or pre-existing lid laxity→Canthopexy or canthoplasty + transconjunctival (lower ectropion risk)
5. Marked tear trough with pseudo-prolapse from malar deficit→Preseptal fat transposition. Add fat grafting if the case is difficult
6. Skeletonised eye (volume deficit, not excess)→Autologous fat grafting in tear trough and tear valley. Do not resect
7. Infraorbital skin rhytidosis without major skin excess→35% trichloroacetic acid peel instead of extending the resection

Characterising the dark circle: not all are surgical

Red flags before indicating surgery

Uncontrolled symptomatic dry eye, active thyroid eye diseaseOrbital involvement of Graves’ disease, with globe protrusion; contraindicates manoeuvres increasing corneal exposure, recent refractive surgery and a markedly negative vector all require rethinking the indication or, at minimum, the consent. In a patient with previous blepharoplasty, assume the septum is scarred and the anterior lamella may already be short: measure MRD2 and test forced closure before resecting anything. It is also worth photographing pre-existing asymmetry — canthal, groove and brow — because patients discover it after surgery, not before.