In vivo increase of the human lens equatorial diameter during
accommodation.
Schachar, Ronald A., Celso Tello, Donald P. Cudmore, Jeffrey M.
Liebmann, Truman D. Black, Robert Ritch.
Department of Physics, University of Texas at Arlington, PO Box
796728, Department of Physics, University of Texas at Arlington,
Glaucoma Service, New York Eye and Ear Infirmary, Professor,
Department of Physics, University of Texas at Arlington, Glaucoma
Service, New York Eye and Ear Infirmary
APStracts 3:0119R, 1996.
The movement of the human lens equator during accommodation was
examined in vivo. High resolution ultrasound images of the lens
equator were obtained from young human subjects whose amplitude of
accommodation was controlled with 1% tropicamide and 2% pilocarpine.
To avoid errors that otherwise arise from eye rotation or other
movement, the cornea and sclera were used as positional references in
comparative studies of the video images obtained from the
unaccommodated and accommodated states. During accommodation the
movement at the lens equator involved small displacement; i.e., less
than 100 microns, and the equator did not move anteriorly or
posteriorly but peripherally towards the sclera. These results
indicate that the lens equator is under increased zonular tension
during accommodation in contradiction to Helmholtz's widely accepted
theory of accommodation.
Received 11 October 1995; accepted in final form 22 March 1996.
APS Manuscript Number R641-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 April 96