Purchase this article with an account.
Saramati Narasimhan, Altricia Wilson, James Nearing, Christian Billotte, Jason Watling, Fabrice Manns, Robert C. Augusteyn, Arthur Ho, Jean-Marie A. Parel; Preliminary Investigation On The Dynamics Of Accommodation In An Ex Vivo Accommodation Simulator: Natural Versus Refilled Lens. Invest. Ophthalmol. Vis. Sci. 2011;52(14):852.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To evaluate the feasibility of quantifying the dynamics of accommodation in a lens stretcher (EVAS) in a natural (NL) and refilled (RL) lens.
The accommodative apparatus of a human eye (age=14yr, PMT 72hr) was mounted in EVAS and stretched to a maximum radial displacement of 2.5mm. After settling for 20s, the load was released at a rate of 0.5mm/s. The coronal view during release was recorded using an operation microscope coupled with a video system. Ciliary and capsule diameters were measured on 146 frames over the 5s release period. At the end of the experiment, the lens was extracted, the empty capsule refilled with a siloxane-based polymer, and the experiment was repeated on the refilled lens.
The change in capsule diameter (CD) was greater for the RL than the NL (0.66mm compared to 0.45mm respectively, over 4s). Fitting to an offset exponential decay model, the accommodative change in CD of the NL exhibited a greater exponential curvature (CD=9.43+0.699e-0.633t) than the RL (CD=8.17+1.61e-0.183t). This suggests that the NL has a marked viscous component in its mechanical properties while the RL is much closer to being elastic. A similar response was seen for the change in diameter of polymer outline in the RL.
The dynamic response of accommodation can be quantified on an EVAS using video-image analysis. Quantitative and qualitative differences can be seen in the accommodation response of NL and RL on the EVAS. The NL exhibits a visco-elastic type response while the lens refilled with siloxane-based polymer exhibits a more elastic behaviour.Support: NIH 2R01EY14225; Australian Federal Government CRC Program (Vision CRC); NIH P30EY14801; Florida Lions Eye Bank; Research to Prevent Blindness; Henri and Flore Lesieur Foundation (JMP).
This PDF is available to Subscribers Only