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O. Yehezkel, S. Ben Yaish, A. Zlotnik, M. Belkin, Z. Zalevsky; A Novel Myopia Correcting Lens Which Reduces the Need for Accommodation for Near Vision Tasks. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1799. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Accommodative effort during childhood is associated with the progression of myopia. We developed a new type of lens that, unlike traditional optical lenses is neither refractive nor diffractive. This lens is based on Extended Depth Of Focus (EDOF) technology that spreads the depth of focus for a given lens or imaging system, with minimal loss of energy. Thus this lens potentially enables the visual system to focus on near and distance objects simultaneously without need for accommodation. Therefore, the use of the new lens in corrective optics at the appropriate ages may reduce the need for accommodation and possibly diminish myopization.
The functionality of the lens as depth of focus extender was checked first in simulation with human eye model on an optical design software and the simulation results were verified on an optical bench. Tests on small trial group were then conducted on 5 myopic subjects with BCVA of 6/6 for the far distance (ETDRS) and with age range of 24-35 years. In order to test our lens we reduced 1.00 D from their optical correction and added the EDOF. We also measured contrast sensitivity, color vision and stereo tests while wearing the EDOF lens. In order to verify the EDOF lens ability to reduce or prevent the need for accommodation for near, 10 presbyopic subjects with addition requirements of 1.75-2.00D were used.
The results on the optical bench showed extension of depth of focus equivalent to 2.50 D. The experiments on trial group showed that the EDOF lens corrected 1.00 D of myopia. The presbyopic subjects' testing showed that the EDOF lens corrected their far and near vision to 6/6 and J1 respectively (i.e. improvement of 2.00 D). Stereoscopic and color vision as well as contrast sensitivity were not affected.
The EDOF lens is capable of correcting up to 1.00 D of myopia. This ability to correct low myopia coupled with its effect in reducing the necessity for accommodation for near vision suggests that it may be tested for the mitigation of accommodation-induced component of myopia.
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