A longitudinal study of vergence adaptation in incipient presbyopia

Baker, Fiona J. and Gilmartin, Bernard (2003). A longitudinal study of vergence adaptation in incipient presbyopia. Ophthalmic and Physiological Optics, 23 (6), pp. 507-511.


Background: To investigate vergence adaptation during the incipient phase of presbyopia, when the amplitude of accommodation approaches the level where the first reading addition is required. The study aimed to assess the ability of the vergence system to counteract changes in the component contributions to the overall vergence response with the decline in the amplitude of accommodation in presbyopia, although previous reports on the nature of changes in accommodative, tonic and proximal vergence are equivocal. Methods: Using a 'flashed' Maddox rod technique, an assessment of vergence adaptation to 6 Δ base-out and 6Δ base-in prism was made for 28 subjects (aged 35-45 years at the commencement of the study). The measurements were taken four times over a 2-year period. Results: Using a repeated measures analysis of variance, the results show that with the decline in amplitude of accommodation, there is a statistically significant reduction in the magnitude of vergence adaptation to both base-out (p < 0.05) and base-in prism (p < 0.01). Conclusions: This study shows that with ageing, there is a decrease in the ability of the slow vergence mechanism to overcome a change in fusional vergence demand and would suggest that either the fast component of fusional vergence must cope with any change in fusional vergence demand or that the sum of the accommodative, tonic and proximal vergence responses are virtually stable with age. © 2003 The College of Optometrists.

Publication DOI: https://doi.org/10.1046/j.1475-1313.2003.00145.x
Divisions: Life & Health Sciences > Optometry
Life & Health Sciences > Ophthalmic Research Group
Life & Health Sciences
Uncontrolled Keywords: accommodation,presbyopia,prism,vergence adaptation,Ophthalmology,Sensory Systems,Health Professions(all)
Full Text Link: http://onlineli ... 0145.x/abstract
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
Published Date: 2003-11
Authors: Baker, Fiona J.
Gilmartin, Bernard

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