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Magnus Andersson, Baskar Theagarayan; Effect of Age on Amplitude of Accommodation in Bolivia. Invest. Ophthalmol. Vis. Sci. 2013;54(15):4254.
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© ARVO (1962-2015); The Authors (2016-present)
The purpose of this study was to investigate the impact of age on Amplitude of Accommodation (AA) in a Bolivian population and compare it with previously published data. We were also interested in finding out the age of onset of Presbyopia in this population.
A sample of 197 Bolivian subjects aged between 8 to 60 years, attending three different field clinics provided by Vision For All (non-profit organization, Sweden) was used in the study. All the subjects were refracted binocularly and had at least best correction Visual acuity of 20/25. None of the subjects had any visible strabismus or ocular pathology. The AA was measured using the push-up and push-down method with a Royal Air Force (RAF) ruler. The ruler has both a metric scale in centimeters and a dioptric scale. The subjects were asked to read letters of N5 print size and report first sustained blur in push-up method and first sustained clear in the push-down method. The subjects had their correction in place during the measurements. Among the presbyopic subjects a +2.00D lens was placed as an addition to bring the target within measurable limits. The average of push-up and push-down readings was used as the subjective AA.
Independent samples t-test showed no statistically significant difference between the present and the previous AA studies (p > 0.05). The AA of the Bolivian population was generally lower compared to previous investigations. Regression analysis showed a significant correlation between age and the AA (r = 0.80, p < 0.05). The onset of presbyopia among the Bolivian population was found to be 38 years.
This result supports the theory that there is a lower AA among people in tropical zones compared to those from temperate zones. The onset of presbyopia for this Bolivian population was seven years earlier than the Hofstetter formula would predict and five years earlier compared to Duane’s (Duane A, Trans Am Ophthalmol Soc, 1922; 20:132-157) values.
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