Fig. 4.12 Multifactorial nature of upper eyelid fullness (redundant skin, fat herniation, etc.)

4.4Examination of the Lower Eyelid and Cheek Continuum

The inferior midface analysis can be subdivided to the skin, the lower eyelids, and the cheeks. These structures should be inspected independently, as well as a continuous unit [16].

The skin should be evaluated for the effects of age, sun exposure, and heritable disease. With time and loss of elasticity, the eyelids and cheeks may exhibit laxity. The presence of skin conditions, pigmentation, rhytids, and scars are also important considerations. Depending on the texture, thickness, and degree of solar damage, skin-resur- facing techniques may be indicated instead, or in conjunction with, incisional procedures (Fig. 4.16). The amount of redundant skin should also be noted to avoid excessive skin resection [17].

Orbital fat herniation, evident through the eyelids, may contribute to the aging face appearance (Fig. 4.17). Orbital septal weakening, orbicularis atrophy, and supporting ligamentous laxity, combine to incite orbital fat protrusion. Examining the patient in up-gaze position may assist in identifying problematic fat compartments [18, 19].

Several relationships and measurements help in the appraisal of the lower eyelid position. The lateral canthus is usually 2–3 mm higher than the medial canthus. The eyelid margin should rest slightly above or at the level of the inferior

limbus. Eyes should be assessed for scleral show, which is present when the lid margin rests below the limbus. Scleral show can be present due to lid retraction, exophthalmos, ectropion, or a combination of these. In prominent eyes,

scleral show can be a normal variant; however surgical intervention should not increase the amount [20–22].

The space between the lower eyelid margin and pupil light reflex distance is known as margin reflex distance two (MRD2), which is normally approximately 5 mm. Values higher than 5.5 mm may define lower eyelid retraction. Grave’s orbitopathy, surgery, trauma, and senile eyelid flaccidity are common causes of lower eyelid retraction [23].

Lower eyelid palpation may help identify a middle or posterior lamellar cicatrix, especially in patients who have had prior surgery or trauma. A “finger” technique may indicate a need for additional strategies for lower lid support. With index finger repositioning of the lateral canthus and mimicking the effect of canthal anchoring procedures, a persistent low central eyelid position may be suggestive that a spacer graft may be necessary, for example [24]. In addition, manual elevation of the lower lid should be free without restriction. Limitation of this maneuver (a tethering) may indicate a vertical deficiency of eyelid tissue or cicatrix of internal eyelid tissue to the orbital rim. Surgery including scar lysis, midface elevation, eyelid support, and a spacer graft may be needed in this scenario.

Lower eyelid laxity is an important diagnosis. The tarsoligamentous sling, consisting of the tarsal plate and canthal tendons, provides the skeletal support of the lower lids, and descends with age-related losses in elasticity. Floppy eyelid syndrome is a variant that may occur in younger individuals, who are also often overweight, and

may have sleep apnea. Floppy eyelids often require horizontal eyelid tightening procedures to avoid or improve eye irritation.

Eyelid laxity can be assessed with the snap-test and distraction tests (Fig. 4.18). Pulling the lower eyelid downward and observing the time it takes to return to a normal position accomplishes the snap-test. A swift return to position without blinking is considered normal. Pinching the lower eyelid and pulling it anteriorly, away from the globe accomplish the lid distraction test. Movement of the lid margin greater than 10 mm is considered abnormal and signifies diminished tone. Significant eyelid laxity may be an indication for canthal anchoring to avoid lower lid malposition, lagophthalmos, and eye fissure shape deformity with periorbital procedures.

The eyelid fissure shape is influenced by canthal laxity. With involutional eyelid laxity there is elongation of the vertical palpebral aperture, rounding of the canthal angle, and increased scleral show. The area of the lateral scleral triangle – the “white” triangle whose confines are the lateral limbus, and the lateral upper and lower eyelid, enlarges as the lateral commissure descends (Fig. 4.19) [25–27].

The lower eyelid and midface continuum is an important concept. In youth, the midface exhibits a single convexity shape on lateral view. With age, a convexity–concavity–con- vexity develops, as the midface separates from the lower eyelid at the level of the orbital rim. Hence, the single unit is lost in the aging face (Fig. 4.20) [28].

Volume depletion and weakened midfacial soft tissue support cause the lower eyelid-cheek junction to descend below the orbital rim (Fig. 4.21). The orbicularis oculi muscle, an integral segment of the superficial musculoaponeurotic

system (SMAS), descends and loses tone. Inferiorly displaced midface tissue, in combination with orbital fat prolapse, result in lid-cheek junction contour irregularities: the nasojugal groove medially and the palpebro-malar groove