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Sandeep Kumar, Stephanie VanBeuge, Zachary Berriochoa, Amrita ., Yingbin Fu; Focal ERG analysis on the impact of PCV lesions on retinal function. Invest. Ophthalmol. Vis. Sci. 2016;57(12):No Pagination Specified. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Polypoidal choroidal vasculopathy (PCV) is a variant of wet Age-related macular degeneration (AMD). It is characterized by a network of branching vessels with terminal polypoidal dilations in the choroid. Recently, we have generated a PCV mouse model (Tg44) by expressing human HTRA1 in mouse RPE. TG44 mice exhibit PCV lesions similar to that in human PCV patients. Here, we used TG44 mice to examine the impact of PCV lesions on retinal function.
Focal ERG recordings were collected in both the lesion and non-lesion areas of TG44. WT Littermates were used as controls. For scotopic recording, mice were dark-adapted for 12 hours, followed by recording from very low (-0.93 log cd.s/m2) to high light intensities (3.58 log cd.s/m2). For photopic, mice were adapted with 7-min background light (0.03 log cd.s/m2), followed by recording at 2.38 log cd.s/m2. Flicker ERG at 2-Hz was obtained in the same area at the same light intensity.
At low intensity (1.18 log cd s/m2), scotopic A-wave amplitude in lesion areas was 1.6 times lower than controls (p<0.05), indicating impaired rod function. Scotopic B-wave amplitude was 2.5 times lower than controls (p<0.05). At high intensity (3.58 log cd s/m2), scotopic A-wave amplitude in lesion areas was 2.0 times lower than controls (p<0.001), indicating both rod and cone functions were affected. Scotopic A-wave amplitude in non-lesion areas was 1.5 times lower than controls (p<0.05), indicating abnormal rod and cone function even in non-lesion areas. Cone specific photopic A-wave amplitude in the lesion area was 2.2 (p<0.05) lower than controls. The amplitude of flicker A-wave in lesion and non-lesion areas was 2.7 and 1.8 times lower than controls (p<0.001), respectively, suggesting that cones were affected in both areas. B-wave amplitude for photopic and flicker in lesions was 2.5 times and 3.0 times lower than controls (p<0.001), respectively, suggesting that the function of post-receptor neurons was also compromised.
This is the first study to examine the impact of PCV lesion vs non lesion areas on retinal function. We found that rod, cone and post-receptor neuron functions are impaired in PCV lesions. Retinal function in the non-lesion area was also generally affected although to a less extent than the lesion area.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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