Analysis of the calculation of the amplitude of accommodation

Abstract

The push-up method is routinely used to measure the amplitude of accommodation. In this method the diopter value corresponding to the nearest point that the eye can focus is determined, wearing his neutralizing lens, but not the value of the maximum diopter variation that makes the eye. The aim of this paper is to review the calculation described in the push-up method taking into account the real position of the near point of the eye. In the subjective push-up method, it is calculated the reciprocal of the distance from the lens until the test object at this position of first, slight, sustained blur. We calculated the differences between this value and the ocular amplitude of accommodation, taking into account that the eye is really looking at the image of first blur through the neutralizing lens. Experimental measurements were also taken to determine whether they were similar to theoretical values. The results obtained by the two calculation methods compared were in general significantly different and the difference was greater for young people with high ametropy. The theoretical results were in agreement with the experimental ones. According to the optometric information required must select the appropriate calculation method, since the values obtained in each of them are not comparable.