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Eva Chamorro, Jose Miguel Cleva, Amelia Gonzalez, Melisa S. Subero, Pablo Concepción, Jose Alonso; Proposed tests for measuring viewing fields for Progressive Power Lenses. Invest. Ophthalmol. Vis. Sci. 2020;61(7):555.
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© ARVO (1962-2015); The Authors (2016-present)
This work proposes a method for measuring clear viewing field (at least 0.1 logMAR visual acuity inside the viewing field) when wearing progressive power ophthalmic lenses (PPL). The test for distance vision consists on a rotational platform with a chin rest that allows to control the head rotation in degrees. The test for near vision consists on a testing table with a chart of different lines of letters that allows to determine the clear area for near vision in mm. The goal of this study is to analyze the capability of these methods for measuring differences in viewing fields between different PPL.
Double blind study comprised of 2 phases. In the first one, the test for measuring near viewing field (NVF) was tested in a group of subjects when using a control PPL lens (Lens 1C) compared to a PPL test lens in which near area was optimized using a variable base curve (Lens 1T). In the phase two, the test for measuring distance viewing test (DVF) was tested in a group of participants when wearing a control PPL lens (Lens 2C) compared with a PPL test lens in which distance vision was optimized using null peripheral mean power (Lens 2T). Statgraphics Centurion XVI.II software was used to determine differences between PPLs.
Proposed techniques provided statistical differences in the measurements of viewing field for distance and near vision. The phase 1 comprised a total of 21 participants in which mean NVF was 13.13±3.28mm for lens 1C and 14.32±3.60mm for lens 1T (p=0.006*). The phase 2 comprised 45 subjects in which mean DVF was 45.02±12.33 for lens 2C and 51.33±14.25 for lens 2T (p=0.047). Additional analysis that show differences in NVF and DVF according to type of refractive error and degree of addition are presented in the attached figure.
The proposed methods are valid tools for measuring and comparing clear viewing fields at distance and near vision provided by different PPLs.
This is a 2020 ARVO Annual Meeting abstract.
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