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Alex Zlotnik, Shai Ben Yaish, Oren Yehezkel, Michael Belkin, Zeev Zalevsky; Extended depth of focus spectacles for full visual field presbyopia correction via brain adaptation. Journal of Vision 2010;10(7):1383. doi: 10.1167/10.7.1383.
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© ARVO (1962-2015); The Authors (2016-present)
Extended depth of focus (EDOF) techniques was previously adapted for ophthalmic usage as a solution for presbyopia and astigmatism. The aim of this research is to use the brain adaptation ability in order to produce homogenous EDOF over the full visual field (VF), with EDOF engraving positioned in discrete positions in the optical system. A set of EDOF profiles was engraved every 3mm over the whole external surface of a spectacle lens. We studied 14 presbyopic patients aged 48-68 (average reading addition of 2.2 D., astigmatism of 0.50-1.00 D.). The VF was tested by examining the visual acuity at tens of random points within the VF of about 30 degrees by displaying various Snellen letters. Subjects had to identify the letters, with assigned scores from one to four for the responses: (1) identifying the letter displayed, (2) identifying a similar letter to the one displayed, (3) naming a letter not similar to the one displayed, or (4) not recognizing the letter. Results in LogMAR units: without the EDOF profile: Best corrected visual acuity (BCVA) was -0.01 and distance corrected near visual acuity (DCNVA) was 0.465. With the EDOF spectacle lens: BCVA=0.05 and DCNVA=0.079. Additionally, the EDOF lens overcame up to 1.00 D. astigmatism. Stereo perception, color vision, and contrast sensitivity remained unaffected. In 96% of the VF correct answer was recorded (category 1). In 2%, small errors were measured (category 2). In the remaining 2%, either large errors or no recognition were recorded. The high EDOF performance showed a solution for presbyopia that was obtained over the full VF, allowing good reading ability. This was achieved using brain adaptation process forcing the reader to gaze only through predefined directions that coincided with the discrete locations.
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