Lateral canthal dynamics, correlation with periorbital anthropometric measurements, and effect of age and sleep preference side on eyelid metrics and lateral canthal tendon

To evaluate dynamic and static properties of lateral canthal tendon and involutional periorbital anthropometric and lateral canthal changes with any possible effect of sleep reference side on these changes. Ninety-two healthy adult subjects with a mean age of 43.5 years were enrolled in the study. Lateral canthal tendon lengths (LCT), canthal movement amplitudes, and other periorbital anthropometric parameters were measured. Any effects of age and sleep preference side on anthropometric and particularly lateral canthal tendon measurements were evaluated. Pearson correlation analysis, one-way analysis of variance, and t-test for paired samples were used for statistical evaluation. LCT length was weakly correlated with age, lower lid tractability, horizontal palpebral fissure length, and interpupillary distance and also inversely correlated with margin reflex distance, but not with other measurements. Age was also correlated with lower lid tractability, and with the ratio of LCT to the horizontal palpebral fissure length (LCT-HPFL). No correlation between age and horizontal palpebral fissure length was detected. Age was weakly and inversely correlated with canthal height but not with canthal movement amplitudes. No effect of sleep preference side on LCT length, canthal height, or lower lid tractability was detected. Lateral canthus has a dynamic structure that is not correlated with any other periorbital anthropometric measurements. LCT length is correlated with lower lid tractability, and increases with age, unlike horizontal palpebral fissure that stays constant with increasing LCT-HPFL ratio. Sleep preference side has no effect on the eyelid metrics and LCT.