Abstract
To better understand the mechanisms of tear drainage, the mechanical properties of porcine canaliculus were measured in compression mode while submerged in isotonic fluid by using a dynamic mechanical analyzer. The storage modulus (E′) for the porcine canaliculus is about 3 kPa at 1 Hz and increases to about 5 kPa at 25 Hz. The loss modulus (E″) increases from about 0.8 kPa at 1 Hz to about 4.5 kPa at 25 Hz. The ratio of loss to storage moduli increases with frequency and is about 1 at 25 Hz, which is the relevant frequency during the blink phase. The moduli for 6- to 9-month pigs does not differ significantly from > 2-year-old pigs. The canalicular tissue relaxes at the same timescale as the pressure relaxes in a human canaliculi suggesting that the drainage of tears through the canaliculi is controlled by the mechanical properties of the canaliculi.