Purpose: When horizontal lid laxity is present, determining which lower lid shortening procedure to perform can be a difficult task. The purpose of this study was to analyze and score specific anatomical aspects in patients with lower lid malpositions in order to construct a scoring system to assist the surgeon in choosing the most appropriate procedure based on specific anatomical deformities.
Techniques: 140 consecutive lower eyelid procedures were performed in one year (2005) by a single surgical team with 30 years of canthoplasty experience. Malpositions were evaluated by 1) lamellar deformities (anterior, middle and posterior); 2) malar prominence to lower eyelid to globe spatial relationship (vector analysis); 3) globe and orbital volume approximation (soft tissue to bone distance); 4) tarsoligamentous integrity; 5) palpebral aperture; 6) lateral canthal to medial canthal position; and 7) lower eyelid and cheek junction (midface descent). Four different methods of canthoplasty were utilized for reconstruction of the lower eyelid malpositions. Statistical evaluation was used to determine which parameters where the most reliable indicators of a successful canthoplasty.
Results: Four of the seven criteria were found to be statistically reliable indicators by their ability to choose a successful canthoplasty procedure. These criteria were then used as the basis for the grading scale: 1) sclera show, 2) + or - vector, 3) lateral to medial canthal relationship, 4) lid margin eversion, and 5) distraction test. A Severity Scoring System was thus developed to match the most appropriate canthoplasty technique to the specific anatomical findings (see chart below). The authors feel that by carefully evaluating the specific anatomic deformity in lower eyelid malpositions, and utilizing the resultant Lower Lid Severity Scoring System, the surgeon is more reliably able to choose the optimal lateral canthoplasty procedure thereby reducing unnecessary reoperations.

Points	Technique	Details
0 - 10	I	IRL Canthopexy
11 - 15	II	IRL Canthoplasty
16 - 20	III	TSL Canthoplasty
> 20	IV	Dermal -orbicular pennant + TSLC + HLS + VSG + Mitek/Midface elevation

*Abbreviations: IRLCx, inferior retinacular lateral canthopexy; IRLC, inferior retinacular lateral canthoplasty; TSLC, tarsal strip lateral canthoplasty; HLS, horizontal lid shortening; VSG, vertical skin graft; DOPLC, dermal-orbicular pennant lateral canthoplasty; DOP, dermal-orbicular pennant, LME, lid margin eversion; B-STD, bone to soft tissue distance; HLL, horizontal lid laxity; MLR, midlamellar retraction