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Validation of a measuring device constructed on bases of the principle of the center of rotation of the eye

  • Ophthalmic lenses are ideally measured in accordance with the center of rotation of the eye. Therefore a measuring device was constructed due to this principle to measure lenses with a focimeter. In this work that measuring device was validated. Lenses of ± 4 dpt in spherical and aspherical design were measured across a field of 9x9 measuring points being at 5° distance from each other. This corresponds to a field of view of 40°. The measurement points in x- and y- direction were theoretically calculated to validate the measurement results. Regarding angles of incidence up to 20° it was supposed that the main optical aberration depends on a change in the sagittal and tangential sphere powers which is also defined as astigmatism. Therefore the calculation presents the tangential and sagittal oblique sphere powers depending on the different angles of the line of vision. On average the measurement results and the calculated data of the spherical designed lenses coincide quite good (correlation at 0,98), the systematic deviation of both values on average is 0.01 dpt and the random error (standard deviation) amounts 0.03 dpt on average. The minimum deviation is -0.06 dpt and the maximum is 0.09 dpt. Common focimeters have a measuring inaccuracy of up to 0.06 dpt (Diepes, Blendowske 2002). Therefore the quality of the measured data should be reliable. The aspherical designed lenses were compared to the spherical designed lenses. With increased angles of incidence the astigmatism of the aspherical lenses leads to lower values than the astigmatism of the spherical lenses

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Author:Benjamin Hahn
Advisor:Ulrike Paffrath
Document Type:Bachelor Thesis
Date of Publication (online):2015/08/04
Date of first Publication:2015/08/04
Publishing Institution:Hochschule Aalen
Granting Institution:Hochschule Aalen, Optik und Mechatronik
Release Date:2015/08/04
Tag:Messgerät, Brillengläser, Rotationszentrum, Auge
measuring device, ophthalmic lenses, center of rotation, eye
Number of Pages:V, 60 S.
Faculty:Optik und Mechatronik
Open Access:Open Access
Licence (German):License LogoVeröffentlichungsvertrag für Publikationen mit Print on Demand