The effect of incipient presbyopia on the correspondence between accommodation and vergence

Baker, Fiona J. and Gilmartin, Bernard (2002). The effect of incipient presbyopia on the correspondence between accommodation and vergence. Graefe's Archive for Clinical and Experimental Ophthalmology, 240 (6), pp. 488-494.


Purpose: To investigate the accommodation-convergence relationship during the incipient phase of presbyopia. The study aimed to differentiate between the current theories of presbyopia and to explore the mechanisms by which the oculomotor system compensates for the change in the accommodation-convergence relationship contingent on a declining amplitude of accommodation. Methods: Using a Canon R-1 open-view autorefractor and a haploscope device, measurements were made of the stimulus and response accommodative convergence/accommodation ratios and the convergence accommodation/convergence ratio of 28 subjects aged 35-45 years at the commencement of the study. Amplitude of accommodation was assessed using a push-down technique. The measurements were repeated at 4-monthly intervals over a 2-year period. Results: The results showed that with the decline in the amplitude of accommodation there is an increase in the accommodative convergence response per unit of accommodative response and a decrease in the convergence accommodation response per unit of convergence. Conclusions: The results of this study fail to support the Hess-Gullstrand theory of presbyopia in that the ciliary muscle effort required to produce a unit change in accommodation increases, rather than stays constant, with age. Data show that the near vision response is limited to the maximum vergence response that can be tolerated and, despite being within the amplitude of accommodation, a stimulus may still appear blurred because the vergence component determines the proportion of available accommodation utilised during near vision.

Publication DOI:
Divisions: Life & Health Sciences > Optometry
Life & Health Sciences > Ophthalmic Research Group
Life & Health Sciences
Uncontrolled Keywords: accommodation-convergence relationship,incipient phase,presbyopia,oculomotor system,declining amplitude,accommodation,accommodative convergence response,ciliary muscle,age,near vision response,vergence response,Ophthalmology
Full Text Link: http://www.spri ... tpduupwjrr68vj/
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
Published Date: 2002-12-01
Authors: Baker, Fiona J.
Gilmartin, Bernard

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