Difference in Pupillary Diameter as an Important Factor for Evaluating Amplitude of Accommodation: A Prospective Observational Study.

Miyuki Kubota,Shunsuke Kubota,Kazuo Tsubota,Kazuno Negishi,Hidenaga Kobashi,Masahiko Ayaki

doi:10.3390/jcm9082678

Abstract

Presbyopia is increasing globally due to aging and the widespread use of visual display terminals. Presbyopia is a decrease in the eye’s amplitude of accommodation (AA) due to loss of crystalline lens elasticity. AA differs widely among individuals. We aimed to determine the factors that cause presbyopia, other than advanced age, for early medical intervention. We examined 95 eyes of 95 healthy volunteers (33 men, 62 women) aged 22–62 years (mean: 37.22 ± 9.77 years) with a corrected visual acuity of ≥1.0 and without other eye afflictions except ametropia. Subjective refraction, AA, maximum and minimum pupillary diameters during accommodation, axial length of the eye, and crystalline lens thickness were measured. AA was measured using an auto refractometer/keratometer/tonometer/pachymeter. The difference between maximum and minimum pupillary diameters was calculated. On multiple regression analysis, age and difference in pupillary diameter were both significantly and independently associated with AA in participants aged <44 years, but not in those aged ≥45 years. Our results suggest that the difference in pupillary diameter could be an important age-independent factor for evaluating AA in healthy individuals without cataract. Thus, improving the difference in pupillary diameter values could be an early treatment target for presbyopia.

Highlights

Presbyopia is defined as a decrease in the amplitude of accommodation (AA) of the eye resulting from the loss of elasticity in the crystalline lens
The results showed that difference in pupillary diameter (DPD) had a significant positive correlation with AA (Std β = 0.438, t = 5.246, p < 0.001), meaning that people with greater differences in pupil size during accommodation have a higher amplitude of accommodation
The results showed that DPD had a significant positive correlation with AA (Std β = 0.589, t = 3.285, p < 0.01), indicating that a greater difference in pupil size during accommodation is present in individuals with a higher amplitude of accommodation

Summary

Introduction

Presbyopia is defined as a decrease in the amplitude of accommodation (AA) of the eye resulting from the loss of elasticity in the crystalline lens. The number of patients with asthenopia, neck stiffness, and headache due to the non-correction or under-correction of presbyopia has been increasing [2,3,4,5,6], likely in part because of the widespread use of visual display terminals (VDTs) [7]. The worldwide loss in gross domestic product (GDP) due to the non-correction or under-correction of presbyopia in individuals younger than 65 years old was reported to be $25 billion in 2011, which is equivalent to 0.037% of the GDP [1]. This attests to the gravity of this social problem. In addition to aging, which is the greatest risk factor for the decline in AA, hypermetropia [13], temperature [14,15], female sex [13,16,17], diabetes [15], alcohol intake [13], smoking [18,19], and laser-assisted in situ keratomileusis [20] have been implicated

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