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Abstract Objective To compare visual field width when reading with single vision lenses (SVLs),traditional progressive addition lenses (PALs) and double-surface PALs.Methods It was a cross-sectional study.Thirty-two presbyopic subjects were selected randomly from the Eye Hospital of Wenzhou Medical College,from September 2009 to February 2010.Eighteen males and 14 females aged from 46 to 69 years (average 57.9±7.7 years) with add powers from +1.25 to +2.50 D (average +1.97±0.34 D) participated in the study.Using a single-blind trial,the same subject was tested with SVLs,traditional PALs (Varilux comfort PALs,Essilor,France) and double-surface PALs (HOYALUX FD double surface PAL,HOYA,Japan).The width of the visual field was measured while reading at a distance of 40 cm with the different lenses.A one-way ANOVA was used to calculate the data.Results While reading at 40 cm,the width of the visual field was widest with SVLs (about 24.50 cm),and was smallest with traditional PALs (about 18.00±4.27 cm,range 7.50～24.50 cm),and with double-surface PALs it was 21.04±3.62 cm,range 12.40～24.50 cm.The differences between the 3 groups was significant (F=32.40,P＜0.01).The difference between every two lenses were significant (P＜0.01).Conclusion This study proved that compared with SVLs,PALs provide a narrower visual field width when reading.With the improvement in the design of PALs,its visual field width at near has been improved greatly.The double-surface PALs have a wider visual field when reading,and at the same time these lenses reduce the burden of the eye rotating up and down.A wider visual field provides readers with the benefits of good wearing comfort and performance.
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