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Gareth Harman, Mark E Pennesi; Relationship of Pupil Entry Position and Cone intensity in Flood-Illuminated Adaptive Optics Imaging. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1267.
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© ARVO (1962-2015); The Authors (2016-present)
To examine the relationship between the pupil entry position and reflectivity of cones imaged. We hypothesize that reflectivity will decrease in intensity as the camera alignment is moved from on-axis to off-axis relative to fixation.
The dominant eye of six healthy individuals was imaged using the rtx1 (Imagine Eyes, Orsay France) flood-illuminated adaptive optics camera at nine different positions along the horizontal axis (figure 1). Each image acquisition produced a file containing 40 images. Custom post-processing was performed on each image using MATLAB (Mathworks, Natick Massachusetts) and included sharpening and vignetting adjustment. Fifteen images with the highest summed pixel difference between the original image and the Gaussian filtered image were selected and registered together using i2k Retina Pro (DualAlign, LLC). Twenty cones of interest were selected, and intensity values of the cones were compared across imaging acquisition positions.
Relative to on-axis imaging, average cone intensity remains unchanged .25 mm from 'on-axis' position in either horizontal direction. However, beyond .3 mm, average cone intensity dropped by 20%. Suprisingly, beyond .5 mm, average cone intensity began to increase (see figure 2).
Compared to imaging on axis, imaging off axis along the horizontal plane with the rxt1 flood-illuminated adaptive optics camera produces differences in average cone intensities. Data suggests that average cone intensity decreases as the camera is moved further from the on-axis point of entry. The increased intensity of cones noted at the extreme ranges of off-axis images could be the product of induced blur and distortion. Further examination will be necessary to examine the relationship between blur and entry position.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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