In-vivo imaging of retinal nerve fiber layer vasculature: imaging - histology comparison

Abstract

Background: Although it has been suggested that alterations of nerve fiber layer vasculature may be involved in the etiology of eye diseases, including glaucoma, it has not been possible to examine this vasculature in-vivo. This report describes a novel imaging method, fluorescence adaptive optics (FAO) scanning laser ophthalmoscopy (SLO), that makes possible for the first time in-vivo imaging of this vasculature in the living macaque, comparing in-vivo and ex-vivo imaging of this vascular bed.

Correlation between the radial peripapillary capillaries and the retinal nerve fibre layer in the normal human retina

“…The RPCs are only present in species with a typical macula, such as human and monkey; or species with equivalent specialised visual areas that are associated with a thicker RNFL in the posterior pole such as pig and cat (Henkind, 1967). Both histological and clinical studies have qualitatively described the RPCs to be the most prominent in the arcuate fibre region where the RNFL is also known to be the thickest (Henkind, 1967;Scoles et al, 2009). Numerous pathological changes such as Bjerrum scotoma, cotton wool spots, intra-retinal haemorrhage and ischaemic optic neuropathy all have in common a neural fibre defect that matches the distribution of RPCs and share common risk factors pertinent to ageing (Alterman and Henkind, 1968;Ashton, 1970;Kornzweig et al, 1968).…”

Imaging retinal mosaics in the living eye

“…Tam et al 34 have shown that this technique can reveal the smallest vessels in a way that is superior to conventional fluorescein angiography and with vessel resolution that is comparable to that seen using FAOSLO. 21,33 The greatest advantage of this method over fluorescein angiography is that this technique can be done non-invasively and repeatedly, in both normal and diseased eyes. 34 …”

“…Fluorescein angiography, combined with adaptive optics imaging in FAOSLO has been used to obtain images of the smallest capillaries near the foveal avascular zone (Figure 7a) and of the radial peripapillary capillaries (Figure 7b) in macaque. 23,33 Recently, parafoveal capillaries were visualized with advanced video processing techniques in AOSLO. 34 These motion contrast methods use the change in reflectance caused by blood flowing through the vessels (that is, the variance in the image) to map vessel paths.…”

In vivo two-photon imaging of the mouse retina

“…Thanks to advances in system design and image registration software, imaging of many different cell classes in the retina is now possible in reflectance and single-photon fluorescence imaging modes [5][6][7][8]. Two-photon fluorescence imaging has the potential for imaging both intrinsic and extrinsic fluorophores in the retina using infrared light [9,10].…”