Lower eyelid medial canthal tendon laxity grading: an interobserver study of normal subjects

To describe a simple grading system for medial canthal tendon (MCT) laxity and measure its reproducibility.

Observational case series and interobserver variability study.

Fifty subjects (100 lower eyelids) without eyelid disease. The age range was 19 to 98 years.

Subjects without eyelid pathology or previous surgery were selected. Two ophthalmologists assessed the position of the inferior punctum in relation to the cornea with the patient in primary gaze. Two measurements were made, the first with the lower eyelid at rest and then with the lateral distraction test. Both observers were masked to the other observer's measurements.

Kappa statistics to show the strength of agreement between the two observers for the resting and lateral distraction eyelid positions.

High kappa values were found for resting position (agreement in 92 of 100 eyelids) and for lateral distraction testing (agreement in 85 of 100 eyelids). The range of resting positions was from position -1 to position 1. The range of laterally distracted positions was from position 0 to position 5. Overall, a very high level of agreement was achieved between observers.

This grading system for MCT laxity is simple, easy to learn and reproducible, easier than measuring in millimeters, and has an advantage over merely saying the tendon is "lax" or "not lax." We propose this standardized grading system in the evaluation of patients with entropion and ectropion to identify those patients who may benefit from MCT stabilization/plication.