Accommodative convergence and age

Rosenfield, Mark; Ciuffreda, Kenneth J.

doi:10.1111/j.1475-1313.1990.tb00893.x

Cited by 10 publications

(6 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, there is ample evidence that greater force is required to produce a given change in accommodation as the eye ages 30,230 . Changes such as the observed increase in response AC/A ratio with age 199–202 also appear to refute the Hess‐Gullstrand theory. Studies like those of Fisher 214,216,217 and Glasser and Campbell 30,205 suggest that, as the eye ages, greater force will need to be exerted on the lens and capsule to achieve the same change in accommodation, thus supporting the basic Duane‐Fincham model.…”

Section: Presbyopiamentioning

confidence: 96%

“…Subjects aged over 40 years appear to experience an increase in positive spherical aberration, as they exercise their limited range of accommodation. 133 Early studies of the links between accommodation and convergence as a function of age produced mixed results 198,199 but later studies are more consistent. Bruce, Atchison and Bhoola 200 found that, for subjects aged between 15 and 45 years, the response AC/A ratio increased with age and the response CA/C ratio decreased.…”

Section: Changes In Other Aspects Of Accommodation With Agementioning

confidence: 99%

See 1 more Smart Citation

The eye in focus: accommodation and presbyopia

Charman

2008

Clinical and Experimental Optometry

206

136

View full text Add to dashboard Cite

Current understanding of the anatomy, function and performance of the accommodative system of the young, adult human eye is outlined. Most major current models of the accommodative mechanism are based on Helmholtz's original ideas but, despite of a growing volume of related research, uncertainty continues over the relative contributions made to the overall mechanism by different ocular structures. The changes with age are then discussed. Although the amplitude of accommodation decreases steadily from later childhood, the speed and accuracy of the system within the available amplitude are little impaired until the age of about 40, when the amplitude falls below that needed for normal near work. A review of the available evidence on age-related change in the lens, capsule, ciliary body and other relevant ocular structures confirms that geometric and viscoelastic lenticular changes play major roles in the progressive loss of accommodation. Other factors may also contribute in an, as yet, unquantified way and a full understanding of the origins of presbyopic change remains elusive.

show abstract

Section: Presbyopiamentioning

confidence: 96%

Section: Changes In Other Aspects Of Accommodation With Agementioning

confidence: 99%

The eye in focus: accommodation and presbyopia

Charman

2008

Clinical and Experimental Optometry

206

136

View full text Add to dashboard Cite

show abstract

“…For example, non-adapters to PALs demonstrated slower convergence peak velocity and the reduced ability to change convergence responses compared to subjects who adapted to PALs. It is speculated that since accommodative convergence decreases rapidly with the onset of presbyopia 26 , the adaptability of disparity-vergence may be critical in maintaining single binocular vision in a visually changing environment such as when wearing PALs.…”

Section: Discussionmentioning

confidence: 99%

“…These interactions are readily demonstrated in the form of accommodative convergence and convergence accommodation, which are measured as the AC/A ratio and CA/C ratio, respectively 22–25 . Thus, as accommodative convergence decreases with the onset of presbyopia 26 the role of disparity-vergence gains importance in the maintenance of single binocular vision. Single binocular vision is described as a state of simultaneous vision coordinated through the use of both eyes such that separate images are observed as a single image via the process of fusion 27–30 .…”

Section: Introductionmentioning

confidence: 99%

Adaptation to Progressive Additive Lenses: Potential Factors to Consider

Alvarez

Kim

Granger-Donetti

2017

Sci Rep

View full text Add to dashboard Cite

People develop presbyopia as part of the normal aging process. Most presbyopes adapt to progressive additive lens (PALs), while others do not. This investigation sought to determine whether the ability to modify disparity vergence or phoria was correlated to PALs adaptation. In experiment 1, a double-step paradigm quantified the ability to modify convergence responses in sixteen presbyopes. In experiment 2, thirty-one incipient presbyopes participated in a 5-minute sustained fixation task to evoke phoria adaptation where the magnitude and rate of phoria adaptation were measured. Then, the experiment was repeated after wearing PALs for one month. Linear regression analyses were conducted between the following parameters: near point of convergence, positive fusional vergence at near, vergence facility, net change in the magnitude of phoria adaptation, and the rate of phoria adaptation. The ability to change convergence average peak velocity was significantly greater (p < 0.03) in presbyopic PALs adapters compared to presbyopic PALs non-adapters. The rate of phoria adaptation and vergence facility were significantly greater (p < 0.03) in incipient presbyopic PALs adapters compared to incipient presbyopic PALs non-adapters. Vergence facility and the rate of phoria adaptation may have potential clinical utility in differentiating which patients may adapt to PALs and which ones will have more difficulty.

show abstract

“…In contrast to the universal agreement on the age-related reduction in accommodative amplitude, there has been considerable disagreement concerning age-related changes in the accommodative convergence to accommodation relationship, or AC/A ratio (Ciuffreda and Kenyon, 1983; Rosenfield and Ciuffreda, 1990). Due to the neurological synkinesis between these two oculomotor systems (Ciuffreda and Kenyon, 1983), any change in blur-driven accommodation (including the effort/innervation) will produce a concomitant change in accommodative vergence.…”

Section: Introductionmentioning

confidence: 99%

The AC/A ratio, age and presbyopia

1997

Self Cite

View full text Add to dashboard Cite

Previous reports concerning the effect of age on the AC/A ratio have been equivocal. Therefore, the present study investigated both the stimulus (AC/As) and response (AC/Ar) ratios using a subjective haploscope-optometer in a relatively large sample of subjects (n = 42) over a wide range of ages (22-65 years). The AC/As showed a small but significant decrease with age (approximately 0.04 delta/D/year). When the older subjects (> 45 years of age) were excluded, however, there was no systematic age effect. The AC/Ar exhibited a small but significant increase with age (approximately 0.08 delta/D/year) for subjects under 45 years of age. However, when the older pre-presbyopes and younger presbyopes (35-44 years of age) were excluded, there was no systematic age effect. In subjects 45 years of age and older, the AC/Ar could not be reliably assessed. This was attributed to physiological and instrumentation noise as a result of the minimal change in accommodative response. In the mid-aged subjects (35-44 years of age), the apparent increase in AC/Ar with age was speculated to be due to neural adaptation of the crosslink gain from the accommodative to the vergence system and/or slight intrusion into the upper non-linear response region of accommodation with the measurements. The finding of AC/Ar constancy with age when mid-aged pre-presbyopes and early presbyopes were excluded supports the non-linearity hypothesis, and thus there appears to be no real change in AC/Ar with increased age. The results support the Hess-Gullstrand theory of presbyopia.

show abstract

Accommodative convergence and age

Cited by 10 publications

References 17 publications

The eye in focus: accommodation and presbyopia

The eye in focus: accommodation and presbyopia

Adaptation to Progressive Additive Lenses: Potential Factors to Consider

The AC/A ratio, age and presbyopia

Contact Info

Product

Resources

About