Typically, the refractive test performed by a visually impaired person differs from a general ophthalmologist. For example, special devices such as telescopes can be used to achieve an optimized eyeglass formulation. Macular degeneration is a condition that affects the retina, the light-sensitive mucosa at the back of the eye where images are focused. The macula – the area of the retina responsible for sharp central vision – deteriorates, resulting in blurred vision. This can cause reading difficulties and, in some cases, a blurred or dead spot in the central area of vision. While there is no cure for visual impairment, there is such a thing as vision rehabilitation. Vision rehabilitation teaches a person with visual impairment how to perform daily tasks using new devices such as video magnifiers and talking clocks, and gives them confidence in how to manage their impairment. Some patients with retinitis pigmentosa who do not have useful vision may be eligible for the Argus II retinal® prosthesis. This device partially restores vision to patients who have lost their sight. In some patients, restored vision allows them to autonomously navigate through doors, sidewalks, sort light and dark laundry, or even read large letters. Part 1 of the U.S. definition of right blindness says this about visual acuity: People with night blindness cannot see outdoors at night or in dimly lit indoor spaces such as movie theaters or restaurants.
A variety of eye diseases, genetic disorders and birth defects, as well as age and injury, can affect healthy vision. Sometimes vision loss is too severe to be corrected with lenses and cannot be repaired with modern procedures. These visual impairments do not all work in the same way. Some, such as macular degeneration, undermine central vision without affecting peripheral vision. It is also possible to have a narrowed field of view where central vision is fine but peripheral vision is limited. Other visual impairments include photophobia (inability to tolerate light), diplopia (double vision), visual distortion, and difficulty perceiving sight. 20/200 to 20/400 visual acuity. Also known as severe visual impairment, things that are generally considered trivial can become difficult due to your visual impairment. If your visual acuity in your best eye is 20/200 or less, you are generally considered legally blind. Visual impairment takes many forms and exists to varying degrees.
Visual acuity alone is not a good predictor of a person`s vision problems. A person with relatively good visual acuity (20/40) may have difficulty functioning, while a person with lower visual acuity (20/200) may have no real problems performing daily activities. Visual acuity better than 20/200, but less than 20/70 in the best eye with the best correction. Note that in most states, 20/70 is required to obtain a driver`s license unless the person is referred to a bioptic driving program for special training. (Administration of Rehabilitation Services) While low vision or legal blindness can be limiting, there are many resources and tools to help you live your life with the utmost independence. Depending on the cause of your vision loss, you may be able to benefit from eye exercises and strategies to participate in daily activities. You may also find it helpful to use a stick, talking calculator, special computer software, and other products to help people who are legally blind. Retinitis pigmentosa gradually destroys night vision, significantly reduces secondary vision, and can lead to complete visual impairment. A hereditary disease, its first symptom – night blindness – usually occurs in childhood or adolescence. Vision can also be lost or damaged due to head injuries, brain damage, and stroke.
Signs and symptoms may include decreased visual acuity or field of vision, contrast sensitivity, blurred vision, eye distortion, poor depth judgment, glare, confusion when performing visual tasks, reading difficulties, double vision, headache, dizziness, abnormal posture, and balance problems. There may be one or more causes of poor vision. These are usually the result of disorders or injuries that affect the eye, or a disorder such as diabetes that affects the entire body. Some of the most common causes of low vision include age-related macular degeneration, diabetes, and glaucoma. Visual impairment can also result from eye cancer, albinism, brain injury or inherited eye diseases, including retinitis pigmentosa. If you have these disorders or are at risk of getting them, you also have a higher risk of low vision. Visual acuity refers to a person`s proximity to an object 20 feet away to see it in detail. Normal vision is measured at 20/20. If you had a visual acuity of 20/80, it would mean that you would be able to see details from 20 feet away, just like a person with 20/20 or normal vision from 80 feet away.
Low vision won`t stop you from doing your daily activities, but you may need to adapt and learn new ways to adapt. Low vision is a progressive disease, so it is important to have regular visits to the ophthalmologist. If detected early enough, you can significantly slow down the degenerative effects. Visual impairment is usually a byproduct of other diseases, such as diabetes complications, but can also occur as a result of brain or eye injury. The most common causes of visual impairment are: The severity of visual impairment can be categorized differently for certain purposes. For example, in the United States, we use the term “legal blindness” to indicate that a person is eligible for certain educational or federal programs.