Non-toric extended depth of focus contact lenses for astigmatism and presbyopia correction Shai Ben Yaish 1 , Alex Zlotnik 1 , Oren Yehezkel 1 , Karen Lahav-Yacouel 1 , Michael Belkin 2 and Zeev Zalevsky 3 1 Xceed Imaging ltd, Petach Tikva, Israel 2 Goldshleger Eye Research Institute, Tel Aviv University, Tel Hashomer, Israel 3 School of Engineering, Bar-Ilan University, 52900 Ramat-Gan, Israel ABSTRACT Purpose: Testing whether the extended depth of focus technology embedded on non-toric contact lenses is a suitable treatment for both astigmatism and presbyopia. Methods: The extended depth of focus pattern consisting of micron- depth concentric grooves was engraved on a surface of a mono-focal soft contact lens. These grooves create an interference pattern extending the focus from a point to a length of about 1mm providing a 3.00D extension in the depth of focus. The extension in the depth of focus provides high quality focused imaging capabilities from near through intermediate and up to far ranges. Due to the angular symmetry of the engraved pattern the extension in the depth of focus can also resolve regular as well as irregular astigmatism aberrations. Results: The contact lens was tested on a group of 8 astigmatic and 13 subjects with presbyopia. Average correction of 0.70D for astigmatism and 1.50D for presbyopia was demonstrated. Conclusions: The extended depth of focus technology in a non-toric contact lens corrects simultaneously astigmatism and presbyopia. The proposed solution is based upon interference rather than diffraction effects and thus it is characterized by high energetic efficiency to the retina plane as well as reduced chromatic aberrations. Key words: Presbyopia, astigmatism, contact lenses. I. INTRODUCTION Currently available optical solutions for presbyopic individuals with myopia or hyperopia leave much to be desired. This is especially true for the majority of those patients who are also astigmatic, and in particular those with astigmatism resulting from keratoconus or refractive surgery [1,2]. Bifocal and progressive spectacle lenses are designed to shift the direction of gaze and thus severely limit the functional visual field [3]. Existing contact lens-based solutions for presbyopic patients are unsatisfactory as they depend on diffractive/refractive designs that divide the energy and thus reduce image quality and contrast especially under low-luminance [4]. The use of toric contact lenses as a solution for severe regular astigmatism is often unsatisfactory because of the need to provide a large range of lenses to fit all refractive errors. With regard to severe irregular astigmatism, there is currently no adequate solution. In this paper we describe a novel contact lens based on the principle of extended depth of focus (EDOF) technology [5,6]. Use of this lens solves most of the problems listed above, as it allows simultaneous high-contrast images of both near and distant objects to be formed on the retina, regardless of astigmatism and without loss of visual field. The solution to astigmatism is obtained since due to the EDOF some axial overlapping is generated between the two focal points of the astigmatic lens and the overlapping point is chosen to be the focusing point of the partially accommodating eye. Because the focused image is axially continuous and does not have a set of discrete focusing planes, energy is preserved at all planes and chromatic aberrations are prevented. II. DEPTH OF FOCUS EXTENDED LENS In the EDOF system a pattern consisting of a series of binary annular concentric grooves less than one micron in depth, is engraved around the optical axis on either the front or the back surface of a lens. This pattern includes large spatial features in the lateral domain and thus its operation principle of modifying the light distribution over the retina plane, is