May 2004
Volume 45, Issue 13
ARVO Annual Meeting Abstract  |   May 2004
OpticalAnalysis of Progressive Addition Lenses and Design Constraints
Author Affiliations & Notes
  • J.E. Sheedy
    Optometry, Ohio State University, Columbus, OH
  • Footnotes
    Commercial Relationships  J.E. Sheedy, None.
  • Footnotes
    Support  Ohio State University College of Optometry
Investigative Ophthalmology & Visual Science May 2004, Vol.45, 2765. doi:
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      J.E. Sheedy; OpticalAnalysis of Progressive Addition Lenses and Design Constraints . Invest. Ophthalmol. Vis. Sci. 2004;45(13):2765.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract: : Purpose: To measure and report the widths and areas of the distance, intermediate and near viewing zones of the major available progressive addition lenses (PALs) in order to identify their relative clinical utility at meeting individual patient viewing needs. Data are subsequently analyzed to investigate the relationships between selected key optical parameters and the sizes of the clear viewing areas of progressive addition lenses (PALs). Methods: The optics of 28 PALs currently on the market were measured with a Rotlex Class Plus lens analyzer. PALs were specified with plano distance power and a near add of +2.00 D. Horizontal cross sections were analyzed in 1 mm vertical steps with respect to the fitting cross. Distance, intermediate and near viewing zone widths and areas were calculated. The maximum amount of unwanted astigmatism, minimum zone width (0.50 DC limit), and maximum power rate in the corridor were also recorded for each lens. Correlation coefficients were determined for all relationships. Results: Each of the 3 viewing zone areas had a significant negative relationship with the other (r of –0.4 to –0.8) – indicating design trade–off. Maximum power rate was significantly related to minimum zone width (r=–0.695) which was significantly related to maximum astigmatism (r=–0.616), but there was not a significant relationship between maximum power rate and maximum astigmatism. Higher power rates and narrower minimum zones were significantly related to smaller intermediate and larger near zones (r=0.4 to 0.9). Maximum astigmatism was related to distance zone width (r=0.42 and to intermediate zone size (r=–0.4 to –0.56, but not significantly related to near viewing zone. The power rate and the astigmatism each vary relatively uniformly across each lens. Conclusions: Power rate and unwanted astigmatism each seems a fundamental value in PAL design. The primary basis for this is the high degree of correlation each variable has with itself at different locations on the lens. Power rate and unwanted astigmatism are also independent of one another as assessed by the lack of correlation of their maxima with one another across lenses, lack of correlation of the locations of their maximal values across lenses, and lack of a relationship with one another as a function of vertical level across lenses. Both power rate and unwanted astigmatism, however, have a significant relationship with zone width. Their maxima are significantly related to minimum zone width across all lenses, the locations of their maxima are both significantly related to the location of minimum zone width, and the relationship of each to zone width as a function of vertical level shows significant similarity across lenses.

Keywords: optical properties • aging: visual performance • astigmatism 

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