Purchase this article with an account.
Marco Augustin, Stanislava Fialova, Corinna Fischak, Leopold Schmetterer, Christoph K Hitzenberger, Bernhard Baumann; Ocular fundus pulsation changes as a response to increased intraocular pressure in the posterior rat eye. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4866.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To demonstrate the feasibility of using optical coherence tomography (OCT) for the determination of ocular fundus pulsations in the posterior rat eye along with OCT angiography (OCTA). To study the effect of increased intraocular pressure (IOP) on the ocular fundus pulsation and the perfusion of the posterior rat eye.
A custom-made OCT system for small animal retinal imaging was utilized to image the posterior eye of Sprague-Dawley rats. A multi-functional imaging protocol was applied comprising 512 A-scans and 400 sets of 5 time repeated B-scans. The acquisition time was 15s with an inter B-scan time interval of 7.65ms. Phase differences were calculated between consecutive B-scans and phase drifts due to bulk motion were compensated. The ocular fundus pulsation was determined by dividing the posterior eye into a retinal and chorioscleral region and calculating the phase differences between these regions. The average relative velocity per B-scan was determined and a spectral analysis of the fundus pulsation was performed by calculating the power of the fundamental oscillation and its harmonics. OCTA was calculated from the average phase differences between consecutive B-scans. The blood flux was determined for the retinal plexus in the ganglion cell layer/inner plexiform layer (GCL/IPL) and the capillary bed in the outer plexiform layer. The ocular fundus pulsation as well as the OCTA parameters were determined as a response to an increase of IOP in rat eyes. For this purpose, the anterior chamber was cannulated with a needle connected to a reservoir filled with a NaCl solution. The IOP levels were stepwise increased from 15 to 105 mmHg over a timeframe of approximately 1 hour.
An increase of the fundus pulsation was observed in all animals until 65mmHg before it decreased at higher IOP levels. Increased local pulsatile motion was observed at higher IOP levels around large choroidal vessels. Analysis of the flux revealed a decrease of blood flow in the retinal capillaries above an IOP level of 55mmHg while the flux in the GCL/IPL plexus only dropped above 75mmHg.
A method to investigate the ocular fundus pulsation simultaneously with OCTA in the posterior eye was proposed. The effect of increased IOP in the posterior rat eye was determined and showed substantial changes on the ocular fundus pulsation as well as on the perfusion of the posterior rat eye.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only