Unlike the regular vision disorders of myopia and hyperopia, these patients’ eyes show severe off-axis low vision optics which can cause huge refractive errors. These errors can’t be corrected by wearing glasses, on the contrary patients have lost some of their visions. Vision optical aids may be applied to help patients use the remaining vision sight to tackle their daily lives.

There are wide array of vision optical magnifiers for specific use. It is pretty difficult for patients to have one-for-all aid for different occasions. Patients may need one for reading newspapers, one for cooking and the other for watching TV.

It is very crucial for ophthalmologists to determine the correct power or strength of the magnifier aid for the patient. A correct strength vision optical aid helps enhance patient’s vision optics and ensure to have a joyful life.

Hand-held magnifier is the one form of vision optical aid. Patients need to practice to be accustomed to this new tool. An easy yet useful tip for properly using this vision optical aid is to hold the aid straight and keep the eyes, the magnifier and the target on the same line, otherwise the target will be distorted and will not be seen clear behind the vision optical magnifier.

In fact, there are still many types of low vision aids for reading. Some of them require a prescription from ECPs and others are nonprescription ones. Patients should always get advice from their doctors in devices choosing.

The simplest and most affordable device is handheld magnifier. Variations of handheld magnifiers include that contains reading lamps, the type that is mounted on height-adjustable stands or hand around the neck.

Strong reading glasses and bifocal eyeglasses with high-power reading segments can also be your choice. Reading telescopes can be handheld or mounted onto special eyeglass frames with enhanced nose pads and padded bridges.

Video magnifiers are another more advantageous option, although they cost much more. These devices project printed materials on a closed circuit television (CCTV), monitor or computer screen. The patient can see those materials on the screen, just like watching TV. All common parameters such as magnification degree, brightness, contrast and color are under adjustable. In addition, the gesture of the patient can be more natural.

You can also get portable reading from a special device system. The device rests on your reading materials and magnifies it. And you can read materials on your eyeglasses projected by the device. You hold the device and can move it in any direction to magnify certain parts of a page. The device can also magnify curved surfaces such as cans and pill bottles.

In addition to the above low vision devices, inexpensive non-optical adaptive aids are also helpful. People with low vision may have difficulty recognizing certain objects. Large-print cookbooks, large-numbered playing cards, clocks, telephones and watches are easier for reading. Other “devices” include large felt-tip pens, wide-lined paper, color-coded pill boxes, voice-recording electronic organizers, signature guides etc…

Regardless of any type of vision aids you choose, good lighting is critical. People with impaired vision need a larger amount of ambient light. Natural sunlight is the best for reading, so that low vision patients can sit near a window during daytime reading. If natural lighting is beyond your hand, use “full-spectrum” incandescent bulbs, rather than harsh fluorescent lighting. While the former type is closer to natural sunlight, the latter type causes glare and discomfort. You should choose bright light bulbs or lamps with three-way sockets.

Article Source:http://vision.firmoo.com/others/optical-vision-aids-for-reading.html

Computer operating systems and Internet browsers also allow partially sighted computer users to increase the size of texts and web pages. Commonly used web browsers such as Internet Explorer, Firefox and Safari can enlarge web page texts by pressing the “+” key while holding down the “Ctrl” key. In opposite, “Ctrl” plus “-” can minify pages to normal size and even smaller sizes. Another more convenient way is to scroll your mouse up or down to change text sizes while also holding down the control key.

These common web browsers also provide menu operation to customers for size control. You can find the “Text Size” or “Make Text Larger” command within “View” menu bar at the top of your browser. If you want enlarged mouse pointers and other navigation items, large-print display software can help. Other solutions include screen magnifiers and larger size of LCD displays.

As mentioned before, certain software can read text aloud. This kind of “talking computers” first scans text from sources and then converts it to sounds. For people who have difficulty reading an entire screen, these special voice systems can read aloud both actual text and important navigation items.

Some people may have difficulty in tracing tiny mouse cursor, so that operating systems provide useful keyboard commands for mouse movements. For people accustomed to a mouse, some tips are useful. Ergonomic design is essential to all types of mouses, in case of any hand discomfort such as cramp. Most modern mouses are equipped with a wheel in the center for simple scrolling down and up. A newer version of mouse is wireless optical mouse.

The flicker of traditional cathode ray tube (CRT) monitors is common by abnormal. This problem is always caused by improper screen refresh rates. You should set this rate above 70 Hz. Liquid crystal display (LCD) screens won’t bring flicker problems.

Article Source:http://vision.firmoo.com/others/computer-based-low-vision-aids.html