Digital Image Analysis Of Eye Fundus Images

The goal of the feature extraction and selection is to reduce the dimension of the data. In this experiment the dimension of the AVIRIS and HYDICE images reduced to 20 from 220 and 191 respectively using PCA. From the PCA analysis we can see that image of principal component 1 is brightest and sharpest than other PCA image which is illustrated in figure-2.

Red – retinal arterioles, hemorrhaging, neovascularization, vascular anomalies, vascular tumors, retinal breaks, holes in retinoschisis, cilioretinal artery, and inner portion of thin areas of retina

The dry form is broken down into three stages; Early, Intermediate, and Advanced (National Eye Institute 3). In the Early stage, people have several small or few medium yellow deposits under the retina called drusen. This stage shows no symptoms or vision loss. During the second stage, Intermediate, more medium or even large deposits happen. As this happens, a blurred spot can develop and more light could be needed for reading. Lastly, in the Advanced stage, a breakdown of light-sensitive cells and tissue causes the blurred spot to enlarge and darken. In this latter stage, facial recognition is unlikely unless the person is extremely close. Either form of Macular Degeneration can only be detected by thorough eye exams. The exam should include visual acuity, which measures sight at varied distance intervals. Also, dilation of the eyes will allow an ophthalmologist to check the retina and optic nerve. An instrument called a Tonometer will measure pressure within the eyes (National Eye Institute 6).

In 1960, a little girl named Anna was born. She was a victim of sexual abuse starting at age 2 and continuing throughout her childhood. Her parents thought she was mentally ill, so as a response they had her evaluated and put on medications. After coping with the situation on her own until age 13, she hit a breaking point. She then was admitted into the mental health system, in which she remained for 19 years. She was diagnosed with multiple types of illnesses, but schizophrenia was the most blatant. Anna also showed symptoms of anorexia, bulimia, and obsessive-compulsive personality. The mental health physicians treated her mainly with psychotropic drugs. As a coping mechanism, she continuously tried to hurt herself by putting cigarette burns

Age-related macular degeneration (AMD) can take two possible forms. Neovascular AMD (wet-AMD) or non-neovascular AMD (dry-AMD) as discussed in the introduction. The available treatment involved in curing patients suffering from AMD differs between the two types of the disease. Neovascular AMD has previously been treated by coagulation therapies of the blood vessel present in the fovea (part of the retina where the ability of vision is the highest). These therapies involve the use of infrared laser light to destroy any additional or new vascular cells in the fovea with the objective of avoiding the leakage of blood vessels. This would prevent photoreceptors from further being damaged and so won’t deteriorate vision any further. However,

Retinal vein occlusion is the second leading cause of vascular disorder after diabetic retinopathy.1 Retinal vein occlusions are classified into 3 categories depending on the location of the thrombus formation; branch retinal vein occlusion (BRVO), central retinal vein occlusion (CRVO), and hemi retinal vein occlusion (Hemi-RVO). 7 BRVO is considered to be the most common among the retinal vein occlusions.6 BRVO occurs more often in men than women. Asians (5.7 per 1000) and Hispanics (6.9 per 1000) are at greater risk of developing BRVO than other ethnicities.6 The age range of patients diagnosed with retinal vein occlusion ranges from young as 14 years of age to old as 92 years of age, with 51% of patients being older than 65 years.3 Advancing age is an important risk factor for developing retinal vein occlusions. Prevalence of retinal vein occlusions in 40-49 years old is 1.57 per 1,000, 4.58 per 1,000 in 50-59 years old, 11.11 per 1,000 in 60-69 years old, 12.76 per 1,000 in 70-79 years old, and 10.32 per 1,000 in those older than 80 years.6

Age related macular degeneration (AMD) is the leading cause of blindness in people over the age of 50. Every ten years after the age of 50 the prevalence of this disease increases exponentially. Many different factors contribute to the development of AMD including genetic, environment, and metabolic functions. Aside from smoking, abnormal blood pressure, and an unhealthy diet low in fruits and vegetables, many more studies are concluding that similar inflammatory and oxidative processes seen in other age related diseases are also playing a key role in the development of AMD. This disease affects the central areas of the retina and choroid. In return central vision is impaired while peripheral vision is usually not lost. AMD is seen in two different forms, the earlier nonneovascular (dry) type and the more advanced neovascular (wet) type. Each form has its own specific pathology and unique characteristics that set them apart. Fatty, protein deposits called drusens may be the key risk factor in understanding dry AMD pathology, progression, and treatment. Once the more advanced wet AMD is diagnosed, pathology and treatment are targeted around the formation and destruction of abnormal blood vessels, characteristic of the wet AMD eye. The increasing prevalence of AMD has influenced more investigation into what factors can be modulated to prevent the onset or to stop the progression of AMD. This text will discuss the pathology of drusens and the role of inflammation and

The most frequent ocular complications reported for all the AVM groups, are: vascular occlusions, aneurysm formation, intraretinal haemorrhage, exudation and cystoid macular oedema. Furthermore, neovascular glaucoma and open angle glaucoma have been described as a result of a retinal central vein occlusion [1].

Age-related macular degeneration (AMD) is a common cause of irreversible blindness in the elderly. AMD is characterized by the progression from early to intermediate stages of the disease. The two major advanced forms are the geographic atrophy (GA) AMD and neovascular AMD. GA or “dry” AMD is characterized by loss of retinal pigment epithelium (RPE) cells and outer layers of the neurosensory retina as well as the choriocapillaris. Neovascular or "wet" AMD is characterized by the formation of choroidal neovascularization (CNV), the ingrowth of new blood vessels from the choriocapillaris through Bruch's membrane into the sub pigment epithelium or subretinal

Central retinal vein occlusion (CRVO) is a blockage (occlusion) in the main (central) vein that drains blood away from a layer of tissue at the back of your eye (retina). The retina is the layer of nerve cells in the back of the eye that senses light and sends signals to the brain for vision.

"Hypertensive Retinopathy is a retinal disease and the retinal blood vessels that occur because of uncontrolled blood pressure. Uncontrolled high blood pressure makes the retinal blood vessels become narrow and leak

These characteristics of the glaucoma patient can progress to blindness. Regularly, glaucoma and its treatment have been closely connected with intraocular pressure. In normal tension glaucoma, damage to the optic nerve occurs without any increase in intraocular pressure. Normal tension glaucoma most often occurs in the elderly and can lead to loss of sight and significant disability. Numerous studies indicate that glaucoma patients have altered retinal circulation. Extensive morphological studies describe endothelial proliferations in the retinal vessels of glaucoma patients. [Charlson2011] In study [Evans1999] Evans et al. assert that glaucoma patients demonstrate faulty autoregulation in the retina during posture change: their CRA response to posture variation shows no change. The CRA directly feeds and is the only source of blood supply for the retinal arteries. These distal vessels nourish the retinal ganglion cells and the confluence of unmyelinated nerve fibers anterior to the lamina

This test helps measure the severity of central vision loss. Another exam is the Fluorescein angiogram which according to the National Eye Institute, is done by an ophthalmologist, and requires a fluorescent dye to be injected into the arm. As the dye flows through the blood stream, pictures of the eye are taken, allowing the doctor to see the presence of bleeding or leaking blood vessels at the back of the eye. The final eye exam that doctors may perform in their quest to rule out macular degeneration, is the optical coherence tomography. Kierstan Boyd explains the working of this exam in her article “What is Optical coherence tomography?” as “a non-invasive imaging test that uses light waves to take cross-section pictures of your retina...” (Boyd, K., Oct, 2015). This exam takes scans of the retina and gauges the thickness of each layer in an attempt to account for a degenerative presence or

According to Friedman, progress in the effort to stop or prevent AMD will be slow until the cause is learned. He claims retinal pigmant epithelium damage to be the prominant theory explaining the choroidal circulation changes that lead to AMD. Although Friedmal himself does not subscribe to this theory, other researchers do and use it as a basis for study. Grunwald, Harisprasad, Dupont, M. G. Mguire, Fine, Bruker, A.M. Maguire, and Ho compared choroidal blood flow in subjects with AMD to a control group. They used laser doppler flowmetry to asess the volume, velocity, and flow of blood in the center of the fovea. Ten subjects with no drusen (cellular debris) were compared to 20 subjects with ten or more large drusen. The average visual acuities of the two groups was very close. No significant differences between age, blood pressure, or intraocular pressure was revealed between the subjects. Spraul, G. E. Lang, Grossnik laus, and G. K. Lang questioned the validity of the study. They claim doppler flowmetry to be an imperfect method for such a study because of multiple light scattering properties of the tissue. They also

There are many different procedures that can be taken for the diagnosis of diabetes. A series of light flashes, each at a different wavelength is used to excite various proteins in the eye, each according to a particular length and the proteins emit fluorescent light. The pattern of light emissions reflects the distribution of carious proteins, which changes according to various psychological conditions (Scientific American Medical 22). This new method is based on synchronous fluorescent spectrometry, which combines a detector with a light source to measure the intensity of light emitted by proteins in the eye from each wavelength shown into the eye. A computer then compares the patient's peaks and valleys of such measurements with corresponding spectra form normal and diabetic eyes. Any one of the following three tests shows the