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Valérie Jolivet, Nacer Lakhchaf, Benjamin Rousseau, Jean-Luc Perrin, Isabelle Poulain, Guilhem Escalier; Impact of specific posture for progressive addition lenses customization. Invest. Ophthalmol. Vis. Sci. 2017;58(8):340.
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© ARVO (1962-2015); The Authors (2016-present)
Progressive addition lenses (PALs) offer presbyopes clear vision at any distance but their intrinsic characteristics are more or less appreciated depending on the wearer. We conducted a crossover study to validate a stronger appreciation of PALs whose design is customized according to the wearer’s specific posture.
The per-protocol population contained 51 presbyopes: 25 women and 26 men aged from 45 to 69. Every subject wore successively two pairs of PALs, each for two weeks, in a randomized order. The reference pair consisted of an identical non customized optical design for all participants. The other was a customized version of the reference design modified to fit with the specific posture of the participant recorded during a near-vision task (Poulain, Perrin & Escalier, 2016). The customization process took into account the downward gaze direction, the reading distance and the vertical eye movements’ amplitude to adjust the near vision zone position and the power progression profile of the PAL design. After each wearing period, a questionnaire was self-administrated to assess the quality of vision during static and dynamic activities, the lenses’ bothersome impact and visual symptoms. Each of these topics was scored between 0 (poor) and 10 (well rated) by averaging related items; the scores were compared between the two designs with Student tests for paired data. Correlations were computed to check if the differences in ratings could be explained by the modification of a single PAL parameter (progression length, 85% of addition on progression profile point position).
No difference was found between the mean scores of reference (8.16±1.47) and customized lenses (8.41±1.30) on static aspects (p=.128). The difference in scores for bothersome impact (ref: 8.58±1.92, custom: 9.05±1.30) was close to significance (p=.067). Customized lenses were better rated on dynamic aspects (ref: 8.47±1.31, custom: 8.86±0.94, p=.009) and symptoms (ref: 9.07±1.40, custom: 9.54±0.92, p=.010). No correlation were found between the scores and any single parameter of the PALs (for all, p>.400).
In comparison to a standard version, a PAL design taking into account individual postural behaviour shows a wearer benefit. This cannot be explained by the change in a single parameter of the design and thus is certainly due to the whole lens optimization process.
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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