Abstract
Purpose :
To evaluate the multifocal properties of two brands of multifocal contact lens designs with opposite philosophy designs (steep changes vs smooth changes on the addition values across the optical profile) when interacting with the higher order aberrations persent in 65 healthy eyes.
Methods :
The optical profiles of two brands (Air Optix Aqua - Alcon, and Oasys - J&J), three addition values (Low, Medium, High), and three corrections (-6 D, -3 D, and +1 D) of multifocal contact lenses were measured by using the NIMO instrument (Lambda-X). Afterwards, these 18 multifocal contact lenses were evaluated on a population of 65 eyes.
In order to do that, we developed an algorithm that converted the power profiles obtained with the NIMO to their corresponding wavefronts by reconstructing a multifocal wavefront from the power profile. Then, a standard Fourier procedure was applied to obtain the VSOTF through focus between -1 D and 5 D. Two values were obtained to compare the optical properties: the area under the through focus VSOTF (normalized by the area obtained for the monofocal design) and the interval of acceptable quality through focus.
Results :
The area under the through focus VSOTF ranges from 0.80 (Oasys L) to 1.1 (AOA H) and the range through focus varies from 0.93 D (Oasys L) to 2.4 D (AOA H). The contact lenses manufactured by Alcon shift the VSOTF towards more positive values when the myopic correction increases.
Conclusions :
A new method to evaluate the optical profiles of multifocal contact lenses has been presented. Designs for old presbyopes - AOA H, Oasys H - spread the VSOTF across around 2.5 D through focus. The peak performance of these designs, however, is lower than the one obtained for lenses that are used by young presbyopes – AOA M and L, and Oasys M and L. Designs intended for young presbyopes extend the VSOTF only 2 D but do conserve a higher peak performance (movable by the partial accommodation that young presbyopes still conserve). The Air Optix Aqua Lenses (with smooth transitions on the addition values on the optical profile) have a higher optical performance than the Oasys lenses (steep changes). Oasys lenses (Low and Medium addition) have a poorer through focus performance than a monofocal lens.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.