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Siegfried Wahl, Tim - Tobias Schilling, Saulius Varnas, Arne Ohlendorf; Peripheral design of progressive addition lenses and the lag of accommodation in myopes. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2736.
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© ARVO (1962-2015); The Authors (2016-present)
Insufficient accommodative response, such as the lag of accommodation (LoA) during near work, is assumed to result in myopia progression. The aim of the present study, was to test, if the accommodative response in myopes is different between standard single vision lens (SVL) and progressive addition lenses (PAL) and if there exist differences among PALs with the same addition power having different designs of periphery.
The influence of spherical SVL and four different designs of PALs on the accommodative response was investigated for different near viewing distances (40 cm, 33 cm and 25 cm) in 31 young myopes, aged 18-25 years with a mean spherical equivalent (SE) refractive error of the dominant eye of –2.81 ± 1.46 D (range -5.62D to -0.75D). The refractive error of the non-dominant eye occluded by the infrared-transparent filter was measured using the Grand Seiko WAM-5500 autorefractor while the corrected, dominant eye, was viewing targets at close object distances.
While using standard single vision correction for distance vision, insufficient accommodative responses during near object viewing at all tested viewing distances were recorded. All tested PALs with the +1.50 D addition have significantly reduced the lags of accommodation, and the amount of residual lag was dependent on the peripheral design of the PAL and the object distance. One test design with a more negative horizontal mean power gradient in the lower viewing zone provided consistently the lowest accommodative lag of all lenses tested and for all viewing distances. That lag being statistically significantly lower in a one-tailed Mann-Whitney-test when compared with a standard PAL design that was set as the benchmark, at the shortest 25 cm object distance. This PAL design was also able to bring the accommodative lag to a level below the depth of focus for near working distances down to 33 cm, where it is no longer perceptible.
This investigation suggests that the designs with the more negative horizontal mean power gradient in the lower viewing zone provide a visual stimulus that leads to a lower accommodative lag, which in some cases may drop to below the threshold of the depth of focus even for the shorter reading distances habitually used by children.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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