In this paper, we give a review on automatic image processing tools to recognize diseases causing specific distortions in the human retina. After a brief summary of the biology of the retina, we give an overview of the types of lesions that may appear as biomarkers of both eye and non-eye diseases. We present several state-of-the-art procedures to extract the anatomic components and lesions in ...

Diabetic retinopathy is a micro vascular complication which is characterized by several changes in the retina. Changes occur in the diameter of the blood vessel, microaneurysm, hemorrhage exudates, and the growth of new blood vessels. These changes need to be detected early so that steps for further handling and treatment can be determined. Laser therapy is one of the common therapies for patie...

AN IMAGE MOVES with respect to the retina both when our eves move a nd when the object moves, but in one case we perceive a stationary object, in the other case a moving object. How can we tell the difference? One approach to this question was proposed by Helmholtz (10) over a century ago. He suggested that when efferent impulses go to the eye muscles, other impulses go simultaneously to areas ...

AIM Accurate Heidelberg retina flowmeter (HRF) measurements require correct manual setting of the HRF photodetector sensitivity. The neuroretinal rim produces a weak signal relative to the peripapillary retina. A newly developed HRF alignment and sensitivity protocol, capable of accurate rim measurement, was investigated. METHODS 18 eyes of nine healthy volunteers were examined by HRF. Three ...

This paper presents an automated method for detecting microaneurysms in the retinal angiographic images by using image processing techniques. In the presented method, in order to fade or remove the pseudo images, first retinal images are pre-processed. Then microaneurysms are identified by circular Hough transform. In the existing methods of dete...

IMPORTANCE The retinal vasculature is involved in many ocular diseases that cause visual loss. Although fluorescein angiography is the criterion standard for evaluating the retina vasculature, it has risks of adverse effects and known defects in imaging all the layers of the retinal vasculature. Optical coherence tomography (OCT) angiography can image vessels based on flow characteristics and m...

Recently Arnold (2011) asked “Why is binocular rivalry uncommon?”. He answered in an entertainingly written, provocative article, for which I thank and congratulate him. However, I will argue that Arnold’s answer falls short in two respects and his assumption that rivalry is uncommon is correct for two reasons other than the one he discusses. Binocular rivalry is a phenomenon of human visual pe...

This paper provides the literature survey about detection of diabetic retinopathy (DR) in retina fundus image. This review consists of segmentation of blood vessels and classification of DR. The objective of this paper is to provide the relevant literature in the digital image processing for the detection and classification of DR. It gives the information about various algorithm employed in DR.

I n normal vision the eye is constantly in motion. Small involuntary move­ ments persist even when the eye .is "fixed" on a stationary object. As a result the image of the object on the retina of the eye is kept in constant motion. One movement of the eyeball makes the im­ age drift slowly away from the center of the fovea, the region of maximum visual acuity in which the cone receptor cells ar...