MRI study of the changes in crystalline lens shape with accommodation and ageing in humans
Kasthurirangan, Sanjeev, Markwell, Emma L., Atchison, David A., & Pope, James M. (2011) MRI study of the changes in crystalline lens shape with accommodation and ageing in humans. Journal of Vision, 11(3), p. 19.
Magnetic Resonance Imaging was used to study changes in the crystalline lens and ciliary body with accommodation and aging. Monocular images were obtained in 15 young (19-29 years) and 15 older (60-70 years) emmetropes when viewing at far (6m) and at individual near points (14.5 to 20.9 cm) in the younger group. With accommodation, lens thickness increased (mean±95% CI: 0.33±0.06mm) by a similar magnitude to the decrease in anterior chamber depth (0.31±0.07mm) and equatorial diameter (0.32±0.04mm) with a decrease in the radius of curvature of the posterior lens surface (0.58±0.30mm). Anterior lens surface shape could not be determined due to the overlapping region with the iris. Ciliary ring diameter decreased (0.44±0.17mm) with no decrease in circumlental space or forward ciliary body movement. With aging, lens thickness increased (mean±95% CI: 0.97±0.24mm) similar in magnitude to the sum of the decrease in anterior chamber depth (0.45±0.21mm) and increase in anterior segment depth (0.52±0.23mm). Equatorial lens diameter increased (0.28±0.23mm) with no change in the posterior lens surface radius of curvature. Ciliary ring diameter decreased (0.57±0.41mm) with reduced circumlental space (0.43±0.15mm) and no forward ciliary body movement. Accommodative changes support the Helmholtz theory of accommodation including an increase in posterior lens surface curvature. Certain aspects of aging changes mimic accommodation.
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|Item Type:||Journal Article|
|Keywords:||Presbyopia, accommodation restoration, cataract surgery, equatorial diameter, radius of curvature , anterior chamber depth, anterior segment length, asphericity , lens thickness, mechanism of accommodation, ocular parameters, lens|
|Subjects:||Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000)|
|Divisions:||Current > Schools > School of Chemistry, Physics & Mechanical Engineering|
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Current > Schools > School of Optometry & Vision Science
|Copyright Owner:||Copyright 2011 The Association for Research in Vision and Ophthalmology (ARVO)|
|Deposited On:||20 Mar 2012 09:40|
|Last Modified:||20 Mar 2012 10:04|
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