Some types of vision loss are the result of normal aging, such as the eye-focusing changes typical of people in their mid-forties. This is when close-up objects are no longer clear. They appear blurry. This is called presbyopia. It's an absolutely normal form of vision change and loss that is related to the aging process. This condition is easily corrected with the proper kind of reading glasses, prescription eyeglasses and contact lenses. Other types of vision loss are not normal and are the result of certain diseases that affect the eyes. Examples of this would be the retinopathy caused by diabetes and the onset of AMD, or age-related macular degeneration. Both diseases are the result of pathological changes in the retina of the eye. Both can result in severe vision loss and even blindness. Diabetic retinopathy is at least partially preventable by maintaining good blood sugar level control. There is some evidence that AMD may be prevented, at least to some degree, by certain nutrients, such as zinc, copper and vitamins C and E. Other common causes of vision loss include glaucoma and cataracts.
1 - Diabetic Retinopathy
Excessive and uncontrolled high blood sugar levels can damage the blood vessels within the eye. In turn, these vessels become less and less able to supply the eye with the nutrients and the oxygen it needs for proper function. Symptoms include blurry vision, reduced color vision and black strings or spots, called floaters, within the visual field. In themselves, floaters are not necessarily dangerous. Many people have them, especially those with higher degrees of myopia, or near-sightedness. However, when combined with other symptoms, floaters can be a sign of diabetic eye disease. Once this disease is established or advanced, treatments for it are limited at best. This is definitely a disease best avoided in the first place by carefully keeping blood sugar levels within normal limits as much as possible.
2 - Age-Related Macular Degeneration
Also known as AMD, this disease mostly affects people older than 60. It's a disease of the macula, which is the central portion of the retina of the eye. The retina contains rods and cones, or cells responsible for both black and white and color vision. It's a light-sensitive organ that receives visual information and transmits it to the brain through the optic nerve. The retina is normally flat. In AMD, abnormal blood vessels begin to grow underneath the retina, causing it to uproot and pucker. This causes straight lines to appear wavy. Since the blood vessels aren't normal, they are weak and begin to break open and bleed. This causes further inflammation and damage to the macula, which is responsible for clear central vision. AMD has been compared to looking through a doughnut hole, with the hole portion either blurry or punched out entirely of the visual field.
3 - Cataracts
The lens of the human eye is normally crystal clear. The eye needs the lens to focus clearly and to provide normal vision. The disease of cataracts causes this lens to cloud up with certain proteins, causing a severe decrease in visual acuity. It is like looking through a frosted window. As a rule, cataracts start out slowly and don't impair vision for a long time. Eventually, though, many people will require surgery to replace the cloudy lens with a clear, artificial one. This kind of surgery is both common and usually quite successful. Symptoms such as dim vision, impaired night vision, double vision in one eye, fading of colors, needing brighter light and seeing halos around lights may indicate a developing cataract that may require surgery to restore normal vision. Risk factors for cataract development include smoking, sun exposure to the eyes, diabetes and excessive alcohol intake.
4 - Glaucoma
Glaucoma is a buildup of pressure within the eye. This pressure causes damage to the optic nerve. It can result in blindness. It often has no symptoms. That's why an ophthalmologist or optometrist will check the pressure in the eyes during a routine examination. When symptoms of glaucoma do occur, it's usually later in the disease process. Symptoms may include eye pain, eye redness, nausea, vomiting, blurry vision and seeing halos around lights. Glaucoma can be treated but not cured. Special eye drops can control and slow its progress, relieving symptoms and preserving vision. No one is quite sure why glaucoma happens. While anyone can develop it, glaucoma tends to affect older people over the age of 60.