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Mateusz Tomasz Jaskulski, Ivan Marin-Franch, Paula Bernal-Molina, Norberto Lopez-Gil; The effect of longitudinal chromatic aberration on the lag of accommodation and depth of field. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):6007.
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© ARVO (1962-2015); The Authors (2016-present)
Recently it has been proven that spherical aberration has influence over the depth of field (DOFi) and the accommodation lag (Bernal-Molina et al., OVS, 2014). We study if the longitudinal chromatic aberration (LCA) also plays a role in increasing the DOFi during accommodation, thus providing an effectively larger range of accommodation.
Wavefront aberration maps for three accommodative demands (AD) 0D, 2D, 4D were measured in 4 subjects using a custom-made adaptive optics system equipped with a Shack-Hartmann sensor, a deformable mirror (Mirao 52-e, Imagine Eyes), and a Badal system controlled by the subject. The accommodation was paralyzed with 2 drops of cyclopentolate (1%). The deformable mirror was then set to cancel out the paralyzed aberrations and add the ones obtained for each AD, to the end that the system simulated the optics of the accommodated eye. Subjects looked through the system including the mirror and a 5.7 mm artificial pupil at a target on an OLED microdisplay. The target consisted of 5 Sloan letters (0.1 logMAR) shown in sequence in B&W, red (R, 650nm), green (G, 550nm) and blue (B, 468nm). The luminance was in all cases constant at 12 cd/m2. By means of the Badal system, subjects indicated near and far borders of the perceived DOFi based upon the objectionable blur criterion. The DOFi of the cycloplegic eyes with all the aberrations corrected (VA < -0.3 logMAR) was also obtained in all color conditions.
Intersubject mean values of DOFi were similar between different color conditions: for the AD of 0D we obtained 0.90±0.15D for B&W, 1.10±0.14D for R, 0.95±0.25D for G, and 0.91±0.12D for B. The mean DOFi was also stable between different simulated accommodation conditions, for example the B&W DOFi was 0.9±15D for 0D, 1.0±15D for 2D and 0.8±0.28D for 4D, and 1.0±0.10D for the fully corrected eye. The DOFi due to the chromatic aberration (the dioptric span between the outer limits of the R and B DOFi) was on average 1.9 times larger than the DOFi found for the B&W condition, for each of the AD's.
The values of the B&W and monochromatic DOFi are similar and practically do not change for any of the simulated AD's. However the DOFi due to the full range of LCA is nearly twice as large as the one obtained for the B&W. These results indicate that the presence of an accommodative lag should not be influenced by the presence of chromatic aberration.
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