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Bill Morgan, Ying Khoo, Anmar Rahman, Balaratnasingam Chandrakumar, Ian McAllister, Fred Chen, Dao-Yi Yu; Retinal Venous Occlusion Leads to Multiple Changes in Retinal Vessel Pulse Amplitude Maps.. Invest. Ophthalmol. Vis. Sci. 2019;60(11):PB053.
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© ARVO (1962-2015); The Authors (2016-present)
To use retinal and optic nerve pulse amplitude mapping in central retinal vein occlusion (CRVO) and hemiretinal vein occlusion (HVO) subjects to test whether significant differences in pulse amplitudes and their distribution may exist.
Video photography of retina allied with ophthalmodynamometry was used to measure photoplethysmography (PPG) estimates of blood column pulse amplitude in time with the cardiac cycle using harmonic analysis at each 5 x 5 pixel location (approximately 30 x 30 micron loci). Maps of pulse amplitude values were constructed allowing co-localisation with vascular anatomic features. CRVO, HVO, and normal eyes were examined. The relationships between pulse amplitude, diagnosis and distance from the optic disc centre were analysed in retinal vessels using linear mixed modelling.
82,685 vessel measurements from 26 eyes of 15 subjects (8 male, mean age 68 +/- 16 years) were examined, subdivided into 14 with CRVO, 4 with HVO, and 8 normal. Normal subjects had mean 8.5 units retinal venous pulse amplitude with a rapid drop (attenuation) in amplitude with distance from disc centre (-6 units/disc diameter) and a significant increase in mean amplitude of 0.031 units/mmHg as intraocular pressure rose (p=0.0000, see figure). CRVO and HVO veins had significantly lower mean pulse amplitude (2.5 units, p<0.0072) with an increase with distance from the centre unlike normals (p=0.0000, see figure) and no increase in amplitude with intraocular pressure elevation. HVO amplitudes actually fell with increased IOP (0.04 units/mmHg, p=0.0000). Pulse amplitudes in the retinal arterioles were significantly greater (p<0.0120) and attenuated more rapidly (p=0.0000) in normals compared to HVO and CRVO.
Retinal and arterial pulse amplitudes are significantly reduced in CRVO and HVO with different amplitude relationships to location along the vessel and with intraocular pressure. These features can be seen on amplitude heat maps co-localised with vessel anatomy.
This abstract was presented at the 2019 ARVO Imaging in the Eye Conference, held in Vancouver, Canada, April 26-27, 2019.
Normal and CRVO retinal video frame (A, B) and pulse amplitude maps (C,D) with pules amplitude scale.
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