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Rishabh Gupta, Francesca BARONE, Dara Baker, Devika Bose, Haig Pakhchanian, Irina Bunea, Arvydas Maminishkis, Davide Ortolan, Joe Phillips, Ruchi Sharma, Juan Amaral, David Gamm, Kapil Bharti; Using Adaptive Optics to Evaluate Photoreceptor Regularity in a Porcine Laser Model Mimicking Age-Related Macular Degeneration. Invest. Ophthalmol. Vis. Sci. 2021;62(8):11.
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© ARVO (1962-2015); The Authors (2016-present)
Adaptive Optics (AO) ophthalmic imaging is a rapidly evolving technique that provides ophthalmologists and vision scientists with the ability to resolve characteristics of the retina at a cellular level in vivo. We assessed cone photoreceptor regularity of the porcine retina under varying degrees of laser-induced retinal pigment epithelium (RPE) damage that mimicked age-related macular degeneration (AMD)-like conditions. This tested our hypothesis that AO is a useful imaging technique to evaluate photoreceptor regularity under disease conditions in preclinical porcine models.
AO was performed in n=4 eyes. The rtx-1 was used to image eyes at baseline and reexamine them at biweekly timepoints after laser intervention. We tested micro pulse laser duty cycles (DC) of 1%, 1.5%, 2%, and 3% in rectangular distributions within the cone dense visual streak of the porcine retina. For image analysis, 80x80 pixel regions of interest were analyzed. MATLAB, AODetect software, and an optimized low-pass filter were utilized in quantifying cone photoreceptors in a semi-automated manner. A custom algorithm aided in calculation of cell region and circularity factor. Cone density was defined by the density of recognized cone photoreceptors within an analyzed image segment. Cell region was defined by the region including the cell and the space abutting the borders of the cell. Cell circularity was defined as a quantitative measurement of the cell border curve from 0.0-1.0, where 1.0 was a perfect circle under healthy conditions.
Following RPE damage with laser, all DCs resulted in decreased cone photoreceptor density and cell circularity factor while cell region increased over the course of 4 weeks. Together, these results suggested an increase in cell morphology irregularity in porcine laser models over 4 weeks.
Our results show AO performed on porcine models may prove to be a useful tool in evaluating cone photoreceptor regularity under disease conditions. Our utilization of the rtx1, an AO instrument designed for clinical settings, optimizes our technique for translational purposes. These findings suggest that cone photoreceptor regularity suffers significantly under conditions that mimic AMD over a 4 week period, and help validate AO as an imaging modality to evaluate photoreceptor health at a cellular level.
This is a 2021 ARVO Annual Meeting abstract.
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