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Walter Torres, Alejandro Mira, John Fredy Barrera, Rodrigo Henao, Andrzej Kolodziejczyk; Psychophysical evaluation of the light sword optical element (LSOE) without axial symmetry for presbyopia compensation. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2981.
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© ARVO (1962-2015); The Authors (2016-present)
Traditional methods for presbyopia compensation have some limitations for a good correction. For this reason, in last years new optical elements with extended-depth-focus has been proposed for presbyopia correction. In this work it is evaluated the potential application of the LSOE for that purpose, performing subjective test with young people having artificially evoke presbyopia.
A monocular visual simulator has been implemented. The refractive LSOE, with a range of depth-focus [0.00,3.00] D simulating a contact lens was located at a pupil conjugated plane in the optical setup. Visual simulator is composed of three sections: one section for ocular aberrations measurements; other section is a Badal system (BS) to present different defocus conditions to subjects; and the last section contains the device for projecting dynamic stimuli.<br /> Visual Acuity (VA) of 10 subjects was measured for different defocus. The subjects had Presbyopia induced using Tropicamide. The psychophysical evaluation was performed by a VA tumbling E test in photopic conditions. For the evaluation, the refraction of the subjects was first corrected using the BS. Later, the VA test was made to defocus from -4D till +1D with step of 1D. At each defocus, two forced choice VA tests were performed, with 48 repetitions each one.<br /> Subjects had ages in a range [22, 35] years, with an average of 27.0±4.7 years. They presented a refraction from -1.56 D to +0.66 D (-0.22±0.80 D in average). Further they demonstrated an astigmatism -1.05±0.49 D in average, with a minimum and maximum value -1.79 D and -0.40 D respectively
For the naked presbyopic eye, the expected decreasing behavior of VA with the defocus grade was found. The decimal VA goes from a maximum value of 1.16 for far vision condition, until 0.49 for near vision at -2.00 D. When the LSOE was used for correction, a relatively constant VA in the range of [-3.00,0.00] D was obtained, with a mean decimal VA of 0.85±0.08.
Due to a relatively constant behavior of VA in the range of the designed optical power of the LSOE, it is possible to remark that it presents adequate features for presbyopia correction. Experiments studying the decentering tolerance of the LSOE and subjective contrast sensitivity measurements can complement the LSOE characterization as a presbyopia corrector element.
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