Purchase this article with an account.
P.D. Hamilton, N. Ravi, G. Perry, M. Reilly; The Effects of Quantitative Zonular Stretching on the Topography of the Anterior Surface of Porcine Lenses . Invest. Ophthalmol. Vis. Sci. 2005;46(13):738.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
We plan to investigate the effect of radial zonular stretching on changes of the anterior lens surface utilizing a corneal topographer.
We previously described a computer–controlled dynamic–radial lens stretcher equipped with linear stepper motors and force sensors. Porcine eyes were embedded in soft agar to maintain the physiological shape. After excision of the cornea, an initial topography reading of the anterior lens surface was determined. Subsequently, the lens and the ciliary body were dissected out, and placed in the 4–arm stretcher, with clamps attached to the ciliary body. As the lens was strained by a known amount using the stepper motors, the dynamic force–relaxation was noted and topographical measurements were acquired.
Increasing the zonular tension resulted in the flattening of the central as well as the peripheral curvature of the anterior lens surface. The force–relaxation curve was fitted well with two time constants (τ1 = 65 ± 11 ms, τ2 = 816 ± 59 ms). The figure presents force–relaxation curves showing corresponding changes of radius of curvature in the central portion of the lens.
Our results demonstrate lens flattening with increased zonular tension, which is consistent with Helmoltz’s theory of accommodation.
This PDF is available to Subscribers Only