Document Detail


Three-dimensional magnetic resonance imaging of the phakic crystalline lens during accommodation.
MedLine Citation:
PMID:  21296812     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Purpose. To quantify changes in crystalline lens curvature, thickness, equatorial diameter, surface area, and volume during accommodation using a novel two-dimensional (2-D) magnetic resonance imaging (MRI) paradigm to generate a complete three-dimensional (3-D) crystalline lens surface model. Methods. Nineteen volunteers, aged 19 to 30 years, were recruited. T(2)-weighted MRIs, optimised to show fluid-filled chambers of the eye, were acquired with a General Electric 3T HDx system, using an 8-channel RF head coil. Twenty-four oblique-axial slices of 0.8 mm thickness, with no inter-slice gaps, were acquired to visualise the crystalline lens. Three Maltese cross-type accommodative stimuli (at 0.17, 4.0 and 8.0 D) were presented randomly to the subjects in the MRI to examine lenticular changes with accommodation. MRIs were analysed using a modified version of the freeware software package mri3dX to generate a 3-D surface model. Results. During accommodation, mean crystalline lens thickness increased (F=33.39, P<0.001), whilst lens equatorial diameter (F=24.00, P<0.001) and surface radii both decreased (anterior surface: F=21.78, P<0.001; posterior surface: F=13.81, P<0.001). Over the same stimulus range, mean crystalline lens surface area decreased (F=7.04, P<0.005) with a corresponding increase in lens volume (F=6.06, P=0.005). These biometric changes represent a 1.82 % decrease and 2.30 % increase in crystalline lens surface area and volume, respectively. Conclusion. The results indicate that the capsular bag undergoes elastic deformation during accommodation, causing reduced surface area, whilst the observed volumetric changes oppose the theory that the lens is incompressible.
Authors:
Amy L Sheppard; C John Evans; Krish D Singh; James S Wolffsohn; Mark C M Dunne; Leon N Davies
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-2-4
Journal Detail:
Title:  Investigative ophthalmology & visual science     Volume:  -     ISSN:  1552-5783     ISO Abbreviation:  -     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-2-7     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7703701     Medline TA:  Invest Ophthalmol Vis Sci     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Ophthalmic Research Group, Life and Health Sciences, Aston University, Birmingham, UK;
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