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Received Dec 6, 2017; Accepted Feb 28, 2018
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1. Introduction
Aberrometry is one of the techniques available for the measurement of the optical quality of the eye. It has been clinically applied and shown to be an important diagnosis and evaluation tool. The eye aberrations are affected by several factors, such as age, pupil diameter, refractive error, and the lens accommodation. To have better knowledge of the human eye, it is important to analyze these changes in the ocular aberrations.
Aberrometry uses a wavefront sensor and the results are expressed in Zernike polynomials. The aberrations are susceptible to several factors, such as age, pupil diameter, refractive error, and accommodation, and it is important to analyze these variations for better knowledge of the human eye [1–12].
Accommodation is the process by which the lens changes its power, allowing the eye to focus objects at different distances. Several studies found changes in retinal image quality when accommodation was stimulated and although there are some variations between individuals, these studies show that monochromatic aberrations increase with accommodations levels [7, 13–15]. The spherical aberrations have been reported to change in the negative direction and high-order ocular aberrations have been reported to increase with the accommodation level [8, 16, 17]. This variation can be explained due to changes in the crystalline lens shape during accommodation [15, 18].
Through aberrometry, it is possible to calculate objectively accommodative parameters, such as the accommodative response or accommodative lag [19, 20]. Recently, some authors have evaluated the dynamic properties of accommodation using wavefront sensors [21, 22].
Accommodative dysfunctions are a common visual problem, even in populations of university students [23–28]. It was estimated that 10.8% of the university students had an accommodative excess and in 6.2% the accommodative insufficiency was present [27].
In this paper, we present new methodology to assess the ocular aberrations’ changes with the accommodation eye. This methodology allows in vivo and real-time measurement of ocular aberrations’ changes for different accommodative step stimuli. There are also presented results obtained from real observers, focusing on the applications of this technique to...