Elastic Fiber Characteristics of Lacrimal Tracts to Aging and Inflammation

PURPOSE: To microscopically examine elastic fiber characteristics of the lacrimal tracts in relation to aging and inflammation. METHODS: Histological evaluation of 8 lacrimal canaliculi from 6 East Asian cadavers (age range: 36-87 years) and 14 lacrimal sacs and nasolacrimal ducts from 9 East Asian cadavers (age range: 52-98 years) was performed. The specimens were fixed in 10% formalin and stained with Elastica van Gieson. Elastic fiber characteristics were observed across age groups, and the ratio of flexible and fragmented-thickened-curved elastic fibers (f/ftc) was subjectively estimated using a 4-point scale. RESULTS: In the lacrimal canaliculi, the f/ftc ratios ranged from 3/1 to 4/0 in the third and fourth decades of life. By the seventh decade, approximately half of the elastic fibers were either fragmented, thickened, or curved. In the eighth decade, the f/ftc ratio dropped to 0/4. In the lacrimal sacs and nasolacrimal ducts, the youngest 52-year-old left specimen showed the f/ftc ratio of 3/1 both in the lacrimal sac and nasolacrimal duct. A majority of the specimens from the seventh, eighth, and ninth decades of life demonstrated the f/ftc ratio of either 1/3 or 0/4 in the lacrimal sac and the nasolacrimal ducts. The 87-year-old male's canalicular specimens (right 2/2, left 0/4) and the 77-year-old male's sac specimens (right 0/4, left 1/3) exhibited asymmetrical findings between sides. Three lacrimal sacs in old age demonstrated inflammation with a decreasing number of elastic fibers. CONCLUSION: Elastic fibers in the lacrimal tracts progressively fragment, thicken, and curve with age. Inflammation decreased the number of elastic fibers.