Wide-field Digital Holography for Ophthalmic Lens Metrology and Its Application in Ocular Vision Correction

Abstract

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We have designed a Wide-Field Digital Holography (WF-DH) system for metrology of ophthalmic lenses over the full field of view within a single camera acquisition. For the developed WF-DH system, the reflection wavefront from the object surface is recorded as a digital hologram using a modified Michelson interferometer. The wide-field of view is achieved by employing a telecentric lens geometry. The recorded hologram is reconstructed to obtain the phase of the lens under test and analyzed for measurements. The information obtained is utilized for verifying the vision correction capability of the test lens using ZEMAX simulations. The proposed system is capable of providing precise measurements of Radius of curvature, diameter, thickness and power of lenses with an error of ±1.3%. The measurement is done with non-contact imaging which is different from the current industrial methods like surface contact stylus profilometry or interferometry techniques which utilize reference surface for metrology of optical lenses. Keywords: Digital Holography, Ophthalmic Lens, Wide Field of View, Telecentric Lens.