Reading performance in middle-aged adults with declines in accommodation

Effects of aging, word frequency, and text stimulus quality on reading across the adult lifespan: Evidence from eye movements

Reductions in stimulus quality may disrupt the reading performance of older adults more when compared with young adults because of sensory declines that begin early in middle age. However, few studies have investigated adult age differences in the effects of stimulus quality on reading, and none have examined how this affects lexical processing and eye movement control. Accordingly, we report two experiments that examine the effects of reduced stimulus quality on the eye movements of young (18–24 years), middle-aged (41–51 years), and older (65+ years) adult readers. In Experiment 1, participants read sentences that contained a high- or low-frequency critical word and that were presented normally or with contrast reduced so that words appeared faint. Experiment 2 further investigated effects of reduced stimulus quality using a gaze-contingent technique to present upcoming text normally or with contrast reduced. Typical patterns of age-related reading difficulty (e.g., slower reading, more regressions) were observed in both experiments. In addition, eye movements were disrupted more for older than younger adults when all text (Experiment 1) or just upcoming text (Experiment 2) appeared faint. Moreover, there was an interaction between stimulus quality and word frequency (Experiment 1), such that readers fixated faint low-frequency words for disproportionately longer. Crucially, this effect was similar across all age groups. Thus, although older readers suffer more from reduced stimulus quality, this additional difficulty primarily affects their visual processing of text. These findings have important implications for understanding the role of stimulus quality on reading behavior across the lifespan.

Suppression of presbyopia progression with pirenoxine eye drops: experiments on rats and non-blinded, randomized clinical trial of efficacy

Various methods can correct presbyopia, but all require devices or surgeries. Recently, supplements or warming devices to relieve presbyopic symptoms have been developed, but no eye drops have been developed. We screened certain compounds possibly related to lens degeneration and identified pirenoxine, which has been used for cataracts, as a possible new pharmacologic treatment for presbyopia. We first researched the anti-presbyopic activity of pirenoxine in rats. The lens elasticity significantly (p = 0.028) increased with exposure to tobacco smoke for 12 days, and pirenoxine eye drops significantly (p < 0.001) suppressed lens hardening, which causes presbyopia in humans. In a parallel randomized controlled clinical study of the subjects in their fifth decade of life, the objective accommodative amplitude (AA) decreased significantly (p < 0.01) by 0.16 diopter (D) in the control group, and there was no detectable change in the treatment group after a 6-month treatment period, suggesting that pirenoxine eye drops might prevent progression of presbyopia. Subjects in their sixth decade of life, in whom the AA was already nearly 0 D, did not show similar results. Pirenoxine eye drops might be a new and the first pharmacologic treatment for preventing progression of presbyopia.

Functional Visual Acuity of Early Presbyopia

Purpose

To evaluate visual function in patients with early presbyopia using the functional visual acuity (FVA) test.

Methods

This study included 27 eyes of 27 healthy older volunteers (mean age, 44.1 ± 2.6 years) and 14 eyes of 14 healthy young volunteers (mean age, 28.4±4.8 years). The distance-corrected visual acuity (DCVA), distance-corrected near VA (DCNVA), subjective amplitude of accommodation (AA), and distance and near pupillary diameters were measured. The distance FVA and distance-corrected near FVA (DCNFVA) were measured using the FVA Measurement System. The standard Schirmer test and standard tear break-up time measurement also were performed.

Results

The logarithm of the minimum angle of resolution (logMAR) DCVA was better than 0 in all subjects. The percentages of subjects with logMAR DCNVA below 0 was significantly lower in the presbyopia group than in the young group. The DCNFVA in the presbyopia group was significantly (P < 0.001) poorer than the DCNVA in that group. Significant linear negative correlations were seen between the DCNVA and AA (r = -0.507, P < 0.001) and the DCNFVA and AA (r = -0.681, P < 0.001) in the older subjects. Stepwise regression analysis showed that only the AA was a significant factor predictive of the DCNFVA in the presbyopia group. Tear function parameters were not adopted in the regression model.

Conclusions

Measurement of the DCNFVA can detect decreased AA in early presbyopia better than measurement of the conventional near VA. The DCNFVA is a good index for early presbyopia.