A comparison of the elastic properties of human choroid and sclera.
Multiple strips of choroid (56) and sclera (64) from eight pairs of human eye-bank eyes were subjected to simple tension in a test apparatus to determine the rigidity (modulus of elasticity) of these tissues. The modulus of elasticity of the chorodial complex (choroid-Bruch's membrane-pigment epithelium) was significantly greater in posteriorly located samples than in anteriorly located ones (7.5 +/- 7.0 vs. 2.2 +/- 1.5 x 10(5) N m-2, mean +/- S.D.). The modulus of elasticity for the complex averaged across all locations was 6.0 +/- 2.8 x 10(5) N m-2 and the average stress at failure was 3.3 +/- 1.3 x 10(5) N m-2. The modulus of elasticity for scleral strips also varied with location and averaged 2.9 +/- 1.4 x 10(6) N m-2 for anterior sclera and 1.8 +/- 1.1 x 10(6) N m-2 for posterior sclera at stress levels ranging from 20- to 260 x 10(4) N m-2. There was a significant correlation of scleral stiffness with age (P less than 0.05, r = 0.80). The elastic properties of the choroidal complex may be relevant to the pathogenesis of a variety of ocular diseases, including macular degeneration, angioid streaks, choroidal folds, and choroidal ruptures.
Friberg
T R
TR
Eye and Ear Institute of Pittsburgh, PA 15213.
Lace
J W
JW
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002829:Choroid / Q000502:physiology*; D004548:Elasticity; D006801:Humans; D008875:Middle Aged; D012590:Sclera / Q000502:physiology*; D013718:Tensile Strength