Affiliation:
1. Faculty of Biology Medicine and Health University of Manchester Manchester UK
2. Centre for Myopia Research School of Optometry The Hong Kong Polytechnic University Hung Hom Hong Kong
3. Centre for Eye and Vision Research (CEVR) Hong Kong SAR China
Abstract
AbstractPurposeTo understand and compare the optics of two multiple segment (MS) spectacle lenses (Hoya MiyoSmart and Essilor Stellest) designed to inhibit myopia progression in children.MethodsThe optics of the two designs are presented, together with geometrical optics‐based calculations to understand the impact of the lenses on the optics of the eye. Lenses were evaluated with three techniques: surface images, Twyman–Green interferometry and focimetry. The carrier lens powers and the spatial distribution, powers and forms of the lenslets were measured.ResultsMS lenses as manufactured were found to match most of the design specifications provided by their manufacturers, although some apparent small discrepancies were found. The focimeter‐measured power of the lenslets was approximately +3.50 D for the MiyoSmart and +4.00 D for the highly aspheric lenslets of the Stellest design. For both lens designs, image contrast would be expected to become modestly reduced in the focal planes of the distance‐correcting carrier lenses. Images become much more degraded in the combined carrier‐lenslet focal plane, due to the generation of multiple laterally displaced images formed by adjacent lenslets within the effective pupil. The exact effects observed depended on the effective pupil size and its location with respect to the lenslets, as well as the power and arrangement of the lenslets.ConclusionWearing either of these lenses will produce broadly similar effects on retinal imagery.
Funder
Hong Kong Polytechnic University
Subject
Sensory Systems,Optometry,Ophthalmology
Cited by
1 articles.
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