A simple clinical test for perception of progressive addition lens peripheral image blur. A pilot study

Abstract

Purpose To introduce a simple method for subjective perception of progressive addition lens (PAL) peripheral image blur (PIB). The amounts of PIB induced by traditional PAL trial lenses (plano distant PAL, TPAL) and prescription PAL (FPAL) were also evaluated. Methods Subjects wearing the PALs adjusted their heads laterally to view the fixation target for PIB perception. 38 subjects were randomized and recruited from the Eye’ni optical shop. Outcomes were assessed by the high-contrast visual acuity chart (LogMAR scale), and by subjectively indicating the magnitude of PIB on a scale of 0 to 10 (10 is extremely blur) using astigmatism-sensitive optotype (Polatest ®, Carl Zeiss Vision, Germany). Results Visual acuities (mean ± SD) at the central and temporal fixations were measured at 0 ± 0.03 and 0.2 ± 0.04 with FPAL, and 0 ± 0.03 and 0.1 ± 0.03 with TPAL respectively. Significantly lower visual acuities were found with the temporal fixation than with the central fixation in both PALs (p < 0.001). And significant even reduction at the temporal fixation with FPAL than with TPAL was observed (p < 0.001). For subjective measures of PIB using astigmatism-sensitive optotype, the average score of FPAL (7.4 ± 0.8, ranged 5–9) was found statistically higher than that of TPAL (6.7 ± 0.8, ranged 4–8) (p < 0.01). Conclusions Our proposed simple clinical method appears to facilitate PAL peripheral image blur demonstration, which may help potential PAL wearers to effectively experience the peripheral PAL image blur. Opticians may caution the potential PAL wearers that prescription PAL may induce more peripheral image blur than that with the traditional distant plano PAL trial lenses.