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M. Aldaba, S. O. Luque, F. Díaz-Doutón, M. Arjona, J. Pujol; Measuring Lag of Accommodation With an Objective Method Based on Retinal Image Analysis. Invest. Ophthalmol. Vis. Sci. 2009;50(13):1124.
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© ARVO (1962-2015); The Authors (2016-present)
To develop a novel objective method for measuring lag of accommodation. It is based on obtaining the best retinal image with a double pass system for each accommodative demand. We have compared the results obtained using the double pass system, with results from an autorrefractometer and an aberrometer.
15 young adults were included in the study, with mean values of age 27.4± 2.7 years, subjective spherical refraction -0.25 ± 1.7 D, subjective astigmatic refraction -0.42 ± 0.1 D, best corrected monocular visual acuity 1.22 ± 0.08 and no ocular pathologies. The patients were corrected according to their subjective refraction, and accommodation was stimulated in the range from 0D to 4D, in 1D steps using both negative lenses and push-up method. The subjects had monocular vision and were instructed to focus on an external fixation test. Double pass image acquisition was done using a modified commercial instrument (OQAS, Visiometrics,Spain.). For each accommodative demand, a scanning of the light vergence was made in order to find the best retinal image. Measurements were repeated using an open field autorrefractometer (WAM-5500, Grand Seiko Co, Ltd) and an Hartmann-Shack aberrometer , developed in our laboratory. Lens effectivity formulas were used for the power calculation of the accommodative stimulation and response.
Double-pass image based method gives in general lower values of lag of accommodation. The highest values are obtained whit the autorrefractometer and statistically significant differences have been found. These differences could be explained by the fact that double pass images contain all the information about the factors that degrade the retinal image quality i.e. aberrations and intraocular scattering (Diaz-Douton et al. IOVS 2006).
A new objective method for measuring the lag of accommodation has been developed. It is based on obtaining the best double-pas image for each accommodative demand. Double pass images contain all the information about aberrations and intraocular scattering and therefore this technique can provide more accurate results in lag of accommodation measurements.
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