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E. Logean, E. Dalimier, C. Dainty; Double Pass Intensity Images of a Point Source After Adaptive Optic Correction of Ocular Aberrations. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4196. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To measure the distribution of light intensity in retinal images of a point source after correction of the ocular aberrations.
A close loop adaptive optics system is used to correct the ocular aberrations over a pupil of 6.2 mm in diameter. Through this corrected pupil, the light from a point source illuminates the retina and the back-scattered light is collected to form an image of the retina on a CCD camera. Each pixel of the camera corresponds approximately to 1 µm at the fundus. Flashes of 10 ms of a green (543 nm) HE-NE laser or of a red (675 nm) laser diode with power at the cornea less than 5 µW was used to image the retina of two volunteers (age 27 and 36 years) using different focus positions. For each image, the centroid intensity was determined and a plot of the intensity versus radial distance from the centroid was generated.
The residual wavefront aberrations measured by the wavefront sensor after correction was smaller than 0.1 µm RMS (without tip and tilt) typically from 0.06 to 0.09 µm. The shape of the light distribution in the images of the point source approximately follows a Lorentzian distribution. For the best focus position, the full width at half maximum was 26 ± 3 µm (mean ± standard deviation, n = 3) for the green light without adaptive optics, 10 ± 2 and 11 ± 2 µm for the green light with adaptive optics (for each subject n = 3 and 4), and 33 ± 3 µm (n = 7) for the red light with adaptive optics.
The intensity of a point source of light in the images of the retina obtained after correction of the ocular aberrations spreads over large angles following approximately a Lorentzian distribution with full width at half maximum about 2.5 (green) and 7 (red) times larger than the diffraction limit.
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