What is visual impairment?
Many people have a visual problem at some point in their lives. Some can no longer see distant objects. Others have problems reading the fine print. These types of vision problems are often easily treated with glasses, corrective lenses or contact lenses.
However, when one or more parts of the eye or brain needed for image processing are damaged, severe or total loss of vision can occur, which is called visual impairment. In these cases, vision cannot be fully restored by medical treatment, surgery or corrective lenses such as glasses or contacts.
Visual impairment is a term that experts use to describe any type of vision loss. Some people are blind, and others have partial vision loss.
What causes visual impairment?
Some of the main causes of visual impairment are:
Albinism is a pigment deficiency that causes several physical conditions, the most important being the lack of color in the hair, skin and eyes.
People with albinism often have poor vision, including photophobia (sensitivity to light and glare). They also often have nystagmus (a rapid and irregular movement of the eyes from side to side). For this type of condition, tinted lenses can be prescribed by ophthalmologists.
Cataracts are the leading cause of blindness in the world. A cataract is a clouding of the lens of the eye that causes light to be scattered as it enters the eye, impacting the clarity of the visual image.
Although most cataracts are a natural result of aging, there are other types of cataracts that can result from diseases such as glaucoma, diabetes or eye injuries.
Common symptoms of cataracts include blurred vision, sensitivity to glare or light, double vision, discoloration or yellowing of colors, poor night vision, and an increased need for light to read or perform close-up tasks.
Diabetic retinopathy is a disease that affects people with diabetes, in which high blood sugar levels damage the blood vessels in the back of the eyes, on the retina. When blood vessels rupture, vision is distorted. Scarring may develop and, in some cases, the retina may detach. All of these factors lead to vision deterioration and sometimes blindness.
Symptoms of diabetic retinopathy often begin with blurred vision that usually worsens over time. Teens with diabetes should be sure to get regular eye exams because there are no warning signs of the disease.
Macular degeneration is a pathological condition. It is a gradual and progressive deterioration of the macula, the most sensitive area of the retina, leading to a loss of sharp central vision. Loss of central vision affects acuity, color vision and can also lead to light sensitivity.
Macular degeneration is often age-related (it occurs in older people), but in some cases it can also occur in younger people. Excessive exposure to the sun and smoking can increase the risk of age-related macular degeneration.
Symptoms may include increased difficulty reading or watching television, or distorted vision in which straight lines appear wavy or objects appear larger or smaller than they really are.
Glaucoma, perhaps the most common eye disease in the world, is a progressive condition characterized by an increase in intraocular pressure resulting in damage to the optic nerve and nerve fibers of the retina.
Glaucoma is most commonly seen in the elderly, although babies can be born with the disease and children and teenagers can sometimes be affected as well. People with glaucoma may experience eyestrain, increased frequency of headaches, blurred vision, halos around lights, difficulty seeing in dim light, and sometimes an unresponsive pupil, pain or even a swollen eye.
Visual impairments range from mild to severe and affect people differently. Lindegger Optique’s expert opticians use a variety of procedures and eye tests to evaluate the integrity, health and function of the eye:
- Visual Acuity Test – A person is asked to read a chart of the eye to measure their vision at different distances.
- Visual Field Test – Ophthalmologists use this test to measure the field of vision (the side or peripheral vision) of the eye.
- Tonometry test – This test determines the fluid pressure inside the eye to detect whether or not the patient has glaucoma.
In the evaluation process, the ophthalmologist uses a combination of patient history and eye assessment to determine the type and extent of visual disturbance.
Do you think you have a visual impairment? Make an appointment for an eye exam at Lindegger Optique in Geneva.