Potential use of cubic phase masks for extending the range of clear vision in presbyopes: initial calculation and simulation studies

• Published in: Ophthalmic and Physiological Optics
• Main Authors: Arines, Justo, Almaguer, Citlalli, Acosta, Eva
• Other Authors: Xunta de Galicia, Spanish ministry of Economía y Competitividad
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2017
• Subjects: Plano; Orca
• Online Access: http://dx.doi.org/10.1111/opo.12348; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fopo.12348; https://onlinelibrary.wiley.com/doi/pdf/10.1111/opo.12348; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/opo.12348

Abstract Purpose In this paper we analyse the potential use of a non‐symmetrical optical element, a cubic phase mask, for extending the range of clear vision of presbyopic eyes. Additionally, we will discuss the appropriateness of the visual Strehl ratio to analyse this sort of presbyopic solution based on non‐symmetrical phase masks contrasted with through‐focus retinal images. Methods In order to evaluate the performance of the cubic phase mask we employed computational Fourier Optics to compute the different visual Strehl criteria as well as simulate the retinal images. The through focus real part of the modulation transfer functions and retinal images were computed for four object distances 6.0, 1.0, 0.6 and 0.4 m which correspond to far, intermediate and near vision conditions for optotypes of visual acuity of 0.1 and 0.0 log MAR (Snellen 6/7.5 and 6/6; 0.8 and 1 in decimal Snellen). For the experimental validation we built an artificial eye consisting of a plano‐convex lens with a focal length of 25.4 mm and 0.5 numerical aperture, a variable diaphragm, a 3× objective and an ORCA 285 Hamamatsu Photonics camera 8.1 μm pixel size (resulting in an effective pixel size of 2.7 μm). A set of four different VA charts adapted to monitor different visual acuities (ranging between 0.0 and 0.20 log MAR ) were placed at different object distances 6, 1.0, 0.6 and 0.4 m from the artificial eye. Results Both numerical and experimental validation showed the suitability of the cubic phase mask for extending the range of clear vision of presbyopic eyes, providing at least a visual acuity of 0.1 log MAR (6/7.5 Snellen, 0.8 decimal Snellen) at all distances. The results show that it is possible to choose between promoting far or near vision by changing the magnitude of the defocus component. It is also possible to extend the range of clear vision, by increasing the magnitude of the cubic component. But this increment will cause a reduction in the contrast of the images as it can be observed from the Visual Strehl values and ...