Study Modules > Module IV: Sensory: Vision and Taste/SmellII. VisionB. Visual Conditions and Disorders1. CataractsAccording to the National Eye Institute, “a cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. It can occur in either or both eyes. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.” [ 9 ]The clouding reduces the amount of light that reaches the retina and can cause blurred vision.
Picture from St. LukesEye.com: http://www.stlukeseye.com/FAQcataract.asp [ 10 ] The risk of getting cataracts increases as one age. Other risk factors for cataracts include certain diseases (diabetes), personal behavior (smoking), prolonged use of steroids, environment (long-term exposure to sunlight), eye injury, high cholesterol and triglycerides. 2. GlaucomaGlaucoma describes a group of eye diseases marked by increased pressure within the eyeball. If left untreated, glaucoma can damage the optic nerve and cause loss of vision. The person with glaucoma loses their peripheral vision but has central vision. Over time the person will eventually lose their central vision and become totally blind.
Picture from the National Eye Institute, http://www.nei.nih.gov/health/glaucoma/glaucoma_facts.htm#1 Glaucoma is known as the “silent thief” because vision is lost gradually and the person may not realize there is a problem until it is permanent. It is the leading cause of blindness. Although any person can develop glaucoma, persons at a higher risk for are those with a family history of glaucoma, persons over the age of 60 (particularly Mexican Americans) and African-Americans over age 40. Those with a family history should have regular annual exams for glaucoma after age 30. Regular eye exams after age 45 are necessary for the majority of people. Treatment for glaucoma can involve medications, surgery, or a combination of these. They will not improve the sight that is already lost, but will help improve the vision that remains. It is important to lower the eye pressure in the early stages of glaucoma in order to slow the disease’s progression and help save vision. There are three types of glaucoma: Primary, secondary and closed angle. 3. Macular DegenerationMacular Degeneration is a common eye disease that affects the sharp, central vision of the eye. It prevalence increases with age. It is commonly known as “Age-Related Macular Degeneration or AMD). For Americans over the age of 50, it is the leading cause of vision loss and blindness. It is caused by the hardening of the arteries that provide nourishment to the retina. Central vision deteriorates because it does not receive the oxygen and nutrients it needs to function and thrive. There are two types of macular degeneration : "Dry" and "Wet" Photo from: http://www.stlukeseye.com/Conditions/MacularDegeneration.asp
For some, treatment for AMD may involve laser surgery to stop the blood vessels leaking into the macular. But for most, will need to learn to use low-vision aids (assistive technology) to continue their activities. 4. Diabetic RetinopathyDiabetic Retinopathyis an eye condition caused by the effects of diabetes. It attacks the retina of the eye. Initially, the person will not exhibit any symptoms or notice any vision loss. Diabetic retinopathy has three stages: Early, Second and Final stages.
Photo from: St.Lukes.com http://www.stlukeseye.com/Conditions/DiabeticRetinopathy.asp Treatment for diabetic retinopathy may include laser surgery or vitrectomy. Laser surgery, also known as (photocoagulation), involves making tiny burns on the retina to seal of the vessels and stop the leaks. Vitrectomy is performed when the blood vessels continue to leak after laser surgery. Vitreous is drawn out of the eyeball and is replaced with saline solution or another fluid. [ 12 ] [ previous section | back to top | next section ] |
This example illustrates what a person with advanced macular degeneration sees.
