An example of some of the more common eye diseases can be found below.
Macular degeneration (or age-related macular degeneration, abbreviated AMD) is the leading cause of vision loss in the Western world. The disease affects the retina, the light-sensitive layer of tissue at the back of the eye. This layer has photo-receptors that are stimulated by light and send signals to your brain, thereby generating vision. Specifically, AMD affects the central part of the retina called the macula and this is the portion of your eye that is used when engaging in visual activities that require the finest acuities, such as reading and driving. Macular degeneration occurs in either a dry (atrophic) or wet (exudative) form. In either case, the disease only affects the central vision, typically near the macula, and rarely causes total vision loss. The majority of patients (over 80% of AMD cases) have the dry or atrophic type of macular degeneration. In this form of the disease, the slow deterioration of the retina is coincidental with the formation of small yellow deposits, known as drusen, in the macular region. This accumulation of drusen leads to a thinning of the macular tissues, causing distortions in vision that initially appear as wavelike. The eventual amount of central vision loss is directly related to the location and amount of retinal thinning caused by the drusen. The exudative, or wet form of the disease, is far less common (about 20% of AMD cases), but it is more aggressive and threatening to one's vision. In the wet type of macular degeneration, abnormal blood vessels grow under the retina and macula through a process called neovascularization. These new blood vessels may bleed and leak fluid, thereby causing the macula to bulge or lift up, distorting or destroying central vision. In these circumstances, vision loss may be rapid and severe. Although much research is being done on finding treatments for macular degeneration, no current treatment exists for the more common dry form, and the treatment for the wet form sometimes does not meet patients expectations. So, for many AMD patients, the use of low vision aids for macular degeneration is of great help and allows them to enhance their quality of life and remain independent.
For the millions of diabetes sufferers in the US, microvascular disease can impact a patient’s vision through diabetic retinopathy. Diabetic retinopathy occurs when diabetes damages the tiny blood vessels in the retina. At first, most people do not notice any vision changes. This stage of the eye disease is known as non-proliferative diabetic retinopathy, and may be evident only through bulges in the blood vessels of the retina known as micro-aneurisms. These blood vessels may bleed or leak fluid into the surrounding retinal tissue. Macular Edema Some people also develop a condition called macular edema. This occurs when the blood vessels leak fluid and lipids onto the macula, the part of the retina that allows us see details. The fluid makes the macula swell and blurs vision.Neovascularization Neovascularization is another complication of diabetic retinopathy and can be more threatening to one's vision. In these cases, abnormal blood vessels grow under the retina. These new blood vessels may then bleed and leak fluid, thereby causing the retina to bulge or lift up, distorting or destroying vision. Under these circumstances, vision loss may be rapid and severe. There are many treatments for the various stages of diabetic retinopathy, but to date, it remains a progressive eye disease. Low Vision Aids can complement good diabetic health care as soon as vision loss occurs.
Glaucoma is the categorical name for a group of eye diseases that can affect vision with few or no symptoms. The vision loss suffered from glaucoma is due to damage to the ocular nerve, which is a bundle of nerve fibers that carry visual messages to the brain. Two different forms of glaucoma can occur: open-angle glaucoma or angle-closure glaucoma. Open-angle glaucoma Open-angle glaucoma is the most common form of glaucoma, affecting about three million Americans. It occurs when the eye's drainage canals become clogged over time. The inner eye pressure (also called intraocular pressure or IOP) rises because the correct amount of fluid is not able to drain out of the eye. With open-angle glaucoma, the entrances to the drainage canals are clear and should be working correctly. The clogging problem occurs inside the drainage canals, like clogging that can occur inside a pipe below a drain in a sink.Angle-closure glaucomaAngle-closure glaucoma is also known as acute glaucoma or narrow angle glaucoma. It is much more uncommon and is very different from open angle glaucoma, in that the eye pressure usually goes up very fast. This takes place when the drainage canals get blocked or covered, like a clogged sink when something is covering the drain.When glaucoma causes pressures within the eye to rise to detrimental levels, the pressure can ultimately damage the optic nerve at the back of the eye, thereby causing vision loss. The earlier the disease is diagnosed and treated, the greater the likelihood of avoiding permanent vision loss.Open-angle glaucoma is commonly treated with medication and with great success. Angle-closure glaucoma typically requires surgery to correct the problem. Low Vision Aids can be particularly valuable for sufferers of glaucoma. Although magnification devices are particularly beneficial during the early stages of glaucoma, the use of contrast-enhancing filters and other solutions often prove very helpful.
A cataract occurs when clouding develops in the eye's crystalline lens. The lens is a critical component of the eye, as it helps to focus light onto the retina at the back of the eye. The lens also adjusts the eye's focus, permitting objects to be seen clearly both close up and far away. All cells within the body degenerate and regenerate. As we age, however, proteins can build up on the crystalline lens and obstruct or deflect some of the light that should pass through it. Cataracts can occur as different types, including nuclear, cortical, or other forms. A nuclear cataract is most commonly seen as it forms. This cataract forms in the nucleus, the center of the lens, and is due to the natural aging process. A cortical cataract, which forms in the lens cortex, gradually extends its spokes from the outside of the lens to the center. These often have a star-like shape and appearance. Many diabetics develop cortical cataracts. A cataract starts out small, and at first has little effect on your vision. You may notice that your vision is blurred a little, like looking through a cloudy piece of glass. The cataract may make light from the sun or a lamp seem too bright, causing glare. With cataracts you may notice when you drive at night that the oncoming headlights cause more glare than before. Colors may not appear as bright as they once did. Cataracts are easily treated through surgery for extraction of the cataractous lens and implantation of a synthetic replacement lens. In some cases however, surgery is not an option due to complicating health problems or other reasons. Surgery may also be delayed for various reasons. In these cases, Low Vision Aids can be critical in assisting the cataract sufferer maintain visual functioning.