title: Age-related changes in human peripapillary scleral strain.
abstract: To test the hypothesis that mechanical strain in the posterior human sclera is altered with age, 20 pairs of normal eyes from human donors aged 20 to 90 years old were inflation tested within 48-h postmortem. The intact posterior scleral shells were pressurized from 5 to 45 mmHg, while the full-field three-dimensional displacements of the scleral surface were measured using laser speckle interferometry. The full strain tensor of the outer scleral surface was calculated directly from the displacement field. Mean maximum principal (tensile) strain was computed for eight circumferential sectors (45° wide) within the peripapillary and mid-peripheral regions surrounding the optic nerve head (ONH). To estimate the age-related changes in scleral strain, results were fit using a functional mixed effects model that accounts for intradonor variability and spatial autocorrelation. Mechanical tensile strain in the peripapillary sclera is significantly higher than the strain in the sclera farther away from the ONH. Overall, strains in the peripapillary sclera decrease significantly with age. Sectorially, peripapillary scleral tensile strains in the nasal sectors are significantly higher than the temporal sectors at younger ages, but the sectorial strain pattern reverses with age, and the temporal sectors exhibited the highest tensile strains in the elderly. Overall, peripapillary scleral structural stiffness increases significantly with age. The sectorial pattern of peripapillary scleral strain reverses with age, which may predispose adjacent regions of the lamina cribrosa to biomechanical insult. The pattern and age-related changes in sectorial peripapillary scleral strain closely match those seen in disk hemorrhages and neuroretinal rim area measurement change rates reported in previous studies of normal human subjects.
authors.affiliation: Department of Ophthalmology, Center for Ocular Biomechanics and Biotransport, University of Alabama at Birmingham, 1670 University Blvd., VH 390A, Birmingham, AL, 35294, USA.
authors.forename: Massimo A
authors.initials: MA
authors.lastname: Fazio
authors.forename: Rafael
authors.initials: R
authors.lastname: Grytz
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Morris
authors.forename: Luigi
authors.initials: L
authors.lastname: Bruno
authors.forename: Stuart K
authors.initials: SK
authors.lastname: Gardiner
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Girkin
authors.forename: J Crawford
authors.initials: JC
authors.lastname: Downs
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D012590:Sclera / Q000502:physiology*; D013312:Stress, Physiological; D055815:Young Adult
references.citation: J Glaucoma. 2004 Oct;13(5):356-60
references.pmid: 15354071
references.citation: J Biomech Eng. 2003 Feb;125(1):124-31
references.pmid: 12661206
references.citation: Invest Ophthalmol Vis Sci. 2012 Aug 09;53(9):5326-33
references.pmid: 22700704
references.citation: J Biomech Eng. 2009 May;131(5):051012
references.pmid: 19388782
references.citation: Invest Ophthalmol Vis Sci. 2009 Nov;50(11):5226-37
references.pmid: 19494203
references.citation: Exp Eye Res. 2011 Jul;93(1):4-12
references.pmid: 20883693
references.citation: Invest Ophthalmol Vis Sci. 2006 Oct;47(10):4254-61
references.pmid: 17003413
references.citation: Biomech Model Mechanobiol. 2011 Jun;10(3):371-82
references.pmid: 20628781
references.citation: Am J Ophthalmol. 2001 Jun;131(6):699-708
references.pmid: 11384564
references.citation: J Biomech Eng. 2012 Sep;134(9):091007
references.pmid: 22938374
references.citation: Am J Ophthalmol. 1989 May 15;107(5):476-84
references.pmid: 2653045
references.citation: Ophthalmology. 2009 May;116(5):840-7
references.pmid: 19410941
references.citation: Invest Ophthalmol Vis Sci. 2007 May;48(5):2134-44
references.pmid: 17460272
references.citation: Arch Ophthalmol. 2001 Jun;119(6):875-80
references.pmid: 11405839
references.citation: J Biomech. 2010 Jun 18;43(9):1696-701
references.pmid: 20399430
references.citation: Metab Pediatr Syst Ophthalmol. 1983;7(4):183-8
references.pmid: 6678372
references.citation: Ophthalmology. 2007 Jan;114(1):3-9
references.pmid: 17070596
references.citation: Invest Ophthalmol Vis Sci. 2010 Jan;51(1):295-307
references.pmid: 19696175
references.citation: Mech Ageing Dev. 1998 Dec 1;106(1-2):1-56
references.pmid: 9883973
references.citation: Surv Ophthalmol. 1980 May-Jun;24(6):621-64
references.pmid: 7414505
references.citation: Ophthalmology. 1998 Feb;105(2):216-23
references.pmid: 9479278
references.citation: J R Stat Soc Series B Stat Methodol. 2006 Apr 1;68(2):179-199
references.pmid: 19759841
references.citation: Invest Ophthalmol Vis Sci. 2011 Mar 30;52(3):1896-907
references.pmid: 20881292
references.citation: Curr Opin Ophthalmol. 2004 Apr;15(2):102-6
references.pmid: 15021220
references.citation: Arch Ophthalmol. 1981 Oct;99(10):1795-801
references.pmid: 7295129
references.citation: Arch Ophthalmol. 1997 Aug;115(8):1051-7
references.pmid: 9258228
references.citation: Am J Ophthalmol. 1976 Jun;81(6):761-7
references.pmid: 937430
references.citation: J Glaucoma. 2008 Jun-Jul;17(4):318-28
references.pmid: 18552618
references.citation: Exp Eye Res. 1972 Jul;14(1):29-39
references.pmid: 5039845
references.citation: Invest Ophthalmol Vis Sci. 2011 Jul 29;52(8):5656-69
references.pmid: 21519033
references.citation: Invest Ophthalmol Vis Sci. 2005 Nov;46(11):4189-99
references.pmid: 16249498
references.citation: Arch Ophthalmol. 1989 Jan;107(1):123-9
references.pmid: 2910271
references.citation: Biomed Opt Express. 2012 Mar 1;3(3):407-17
references.pmid: 22435090
references.citation: Ann Biomed Eng. 2010 Apr;38(4):1586-92
references.pmid: 20039133
references.citation: Br J Ophthalmol. 1995 Apr;79(4):368-75
references.pmid: 7742286
references.citation: Invest Ophthalmol Vis Sci. 2004 Dec;45(12):4378-87
references.pmid: 15557446
references.citation: Invest Ophthalmol Vis Sci. 2005 Feb;46(2):540-6
references.pmid: 15671280
references.citation: Arch Ophthalmol. 2002 Jun;120(6):701-13; discussion 829-30
references.pmid: 12049574
references.citation: J Mech Behav Biomed Mater. 2012 Dec;16:181-91
references.pmid: 23182387
references.citation: Invest Ophthalmol Vis Sci. 2000 Sep;41(10):2991-3000
references.pmid: 10967056
references.citation: Am J Ophthalmol. 2002 Oct;134(4):499-512
references.pmid: 12383806
references.citation: Ann Appl Stat. 2011 Jan 1;5(2A):894-923
references.pmid: 22408711
references.citation: Invest Ophthalmol Vis Sci. 2012 Apr 02;53(4):1714-28
references.pmid: 22395883