A second evaluation of the dual-mode AD-IOL was performed by another independent laboratory (Photon Gear Inc.), using Twyman-Green laser interferometry to evaluate change in power with stretching. Again, progressive flattening of the top of the optic was seen with stretching to 0.4 mm and 0.8 mm. Power changed from 34 D in the accommodated state (0 mm stretch) to 8 D at the maximum stretch tested (0.8 mm).
“The interferometer results were consistent with our design specifications and showed that 26 D of accommodative change is possible,” Dr. Beer said. “While that is unheard of for any accommodating IOL, it is far more amplitude than is needed.”
Applying force limitation equations developed from experiments performed with the single-mode AD-IOL, it was predicted that the dual-mode AD-IOL was capable of about 13.8 D of accommodative change.
“That is still more than necessary, but it gives us the latitude to achieve accommodation in the desired range of 3 D to 5 D, while introducing other modifications that we believe are important for mechanical, safety, and image stability reasons,” said Dr. Beer.
“In addition, considering that the force requirement to get the first-, second-, third-, and fourth-diopter change is much less than is needed to get the last few diopters of the 26 D range, the more range capability the lens has, the easier it is for the eye to get the accommodative change it needs with minimal force,” Dr. Beer added,