PURPOSE To investigate the properties and origin of retinal intrinsic signals by functional optical coherence tomography (fOCT) in macaque retinas. METHODS We modified a spectral domain OCT system to be able to give short-duration flashes or continuous light stimulation to the retina of three adult macaque monkeys (Macaca mulatta) under general anesthesia. Changes in the intensities of the OC...

The variability in the spatial orientation of retinal blood vessels near the optic nerve head (ONH) results in imprecision of the measured Doppler angle and therefore the pulsatile blood flow (BF), when those parameters are evaluated using Doppler OCT imaging protocols based on dual-concentric circular scans. Here, we utilized a dense concentric circle scanning protocol and evaluated its precis...

Although retinal vasculitis is common in multiple sclerosis (MS), it is not known if MS is associated with quantitative abnormalities in retinal blood vessels (BVs). Optical coherence tomography (OCT) is suitable for examining the integrity of the anterior visual pathways in MS. In this paper we have compared the size and number of retinal blood vessels in patients with MS, with and without a h...

The ultrastructure of retinal vessels was examined in three eyes from diabetic patients and two eyes from control subjects. In some of the retinal blood vessels of each of the diabetic eyes, the endothelial cytoplasm was thin and had fenestrae. These fenestrations which were seen in both capillaries and venules, were closed by a thin diaphragm. Transendothelial channels were also observed in th...

PURPOSE To describe a case where detection of blood flow in the central retinal artery and the central retinal vein was limited by an artifact evoked by the optic disc drusen. METHODS Case report. RESULTS During color Doppler sonography, examination of optic disc drusen may generate an artifact--the so-called twinkling artifact--which can simulate blood flow and make evaluation of the central...

PURPOSE To unmask the vasoconstricting effect of angiotensin II (Ang II) on retinal smooth muscle by studying its interaction with endothelium-derived paracrine substances. This study focused specifically on determining the changes in vascular diameter and the release of endothelial-derived vasodilators, nitric oxide (NO) and prostaglandin (PG) I2, from isolated retinal microvessels. METHODS ...

This paper presents an analysis of the bifurcations of retinal vessels. The angles and relative diameters of blood vessels in 230 bifurcations were measured using a new automated procedure, and used to calculate the values of several features with known theoretical properties. The measurements are compared with predictions from theoretical models, and with manual measurements. The automated mea...

Photocoagulation is an accepted method of local treatment for proliferative diabetic retinopathy. It has been shown that 73 25 per cent. of eyes with proliferative diabetic retinopathy have new vessels on the optic disc at the initial visit (Taylor and Dobree, I970). These vessels cannot be treated directly by photocoagulation. Aiello, Beetham, Balodimos, Chazan, and Bradley (I969) treated all ...

We present a case of Coats’-like retinitis pigmentosa in a 22-year-old female patient. Both eyes showed the typical funduscopic features of retinitis pigmentosa, and the right eye showed scar formation due to exudative retinal detachment in the temporal peripheral retina with dilatation of the retinal vessels. Fluorescein angiography did not show dye leakage at the scar lesion or the dilated re...

The visual (retinoid) cycle is a fundamental metabolic process in vertebrate retina responsible for production of 11-cis-retinal, the chromophore of rhodopsin and cone pigments. 11-cis-Retinal is bound to opsins, forming visual pigments, and when the resulting visual chromophore 11-cis-retinylidene is photoisomerized to all-trans-retinylidene, all-trans-retinal is released from these receptors....