Low vision, photophobia and aniridia
One of the main problems of people with aniridia, which makes their daily life difficult is low vision and sensitivity to light.
How does it affect life of patients with aniridia?
First, the quality of vision (visual acuity) is low.
Visual acuity is the maximum capacity of the individual to perceive objects. The well see person can count fingers of a hand from a distance of 50 m. If the vision is 20/40, then the patient should be kept at a distance of 20 paces to see what a person with normal vision can see at 40 paces. The decrease in visual acuity in patients with aniridia usually ranges from 20/60 to 20/400. Those with visual acuity 20/200 or worse, are considered visually impaired. For visual acuity testing use special table computer diagnostics.
Second, people with aniridia may have decreased peripheral vision (visual fiel). This is not directly due to aniridia, but rather to glaucoma, which may develop due to structural changes in the eye. If a patient has adequate visual acuity, but has a decreased visual field of 20 degrees or less at its widest diameter, he/she is considered legally blind.
Third, all individuals with aniridia have little or no iris in either eye (sometimes there is a partial iris). As a result of the lack of iris, individuals with aniridia are often sensitive to bright lights and glare, which is usually helped by wearing polarized sunglasses and hats outside and mildly-tinted lenses inside or photochromic lenses. In addition, because light is not being filtered, individuals usually experience reduced acuity as a result of light flooding into the back of the eye (if you have ever had your eyes dilated for a vision test, you may notice that vision is a little "blurry").
Some individuals with aniridia have had success with special contacts with a "painted" iris. However, contact lens use in individuals with aniridia must be closely monitored because contacts can harm the cornea. The type of contact lens and frequency of use is very important.
Fours, people with aniridia have a refractive error. This term used when someone needs glasses for distant or close activities. People with aniridia may have hyperopia, myopia, or astigmatism. People with aniridia are obliged to have glasses by prescription. Recommended high-impact (polycarbonate) and polarization (against glare) lenses. Contact lenses can be used if the cornea is absolutely healthy.
Devices for reading and watching in the distance for patients with aniridia.
Most patients with aniridia problems with near activities. For example, reading newspapers, books, menus, price lists, medications, etc. There are several ways to improve vision.
The most suitable glasses for people with aniridia are bifocal reading glasses. Also, sometimes they need to hold reading material a little closer than normal people. At first, to patients may seem that the distance a little uncomfortable, however, the newspaper will appear larger and, therefore, increase clarity.
Another option - the use of hand-held magnifiers.
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http://www.enhancedvision.com/low-vision-product-line.html
The paper should be non-reflective, and color of the paper and letters should contrast well (for example, a white paper with black letters). It is desirable to use a large font. APHont font was designed specifically for people with poor vision.
For looking in the distance people with aniridia can use different binoculars and monoculars.
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Lighting is also important. You must decide if a bright light over your shoulder helps or vice versa increases glare.