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Updated: Jul 17, 2026
Simulating the Mechanics of Lens Accommodation via a Manual Lens Stretcher
Published on: February 23, 2018
The effect of human in vivo accommodation on crystalline lens stability
Ronald A Schachar1, Carlos Davila, Barbara K Pierscionek
1University of Texas at Arlington, PO Box 601149, Dallas, TX 75229, USA. ron@2ras.com
Aim:
To determine the effect of human in vivo accommodation on the stability of the crystalline lens.
Methods:
Using a dual Purkinje image (DPI) eyetracker, the phase-time difference and amplitudes of Purkinje images I (P(I)) and IV (P(1V)) were measured in 37 normal emmetropic subjects (34 women and 3 men; mean age 19.8, range 18-22 years) when they changed focus from 70 to 15 cm and simultaneously rotated their heads horizontally from side to side or made horizontal saccades between two targets 6.8 degrees apart.
Results:
When the subjects changed focus from 70 to 15 cm and rotated their heads or made eye saccades, the phase-time difference between P(I) and P(IV) decreased. During saccades, the amplitude of both P(I) and P(IV) overshoots significantly increased with focus at 15 cm; however, their ratio (P(IV) overshoot amplitude/P(I) overshoot amplitude) significantly declined.
Conclusions:
The lens is stable during accommodation. The implications of these findings on the mechanism of accommodation are discussed.
