LOW VISION 


What is Low Vision?

Low vision is the term used to refer to a visual impairment that is not correctable through surgery, pharmaceuticals, glasses or contact lenses. It is often characterized by partial sight, such as blurred vision, blind spots or tunnel vision, but also includes legal blindness.


Many newly diagnosed people are referred to us for a low vision evaluation by a low vision specialist.

 

 

Low Vision Evaluation

 

What is a Low Vision Evaluation?

A clinical low vision evaluation assesses whether or not a child will benefit from optical devices such as monocular telescopes and/or magnifiers. An optometrist or ophthalmologist who specializes in low vision and the prescription of optical devices performs the clinical low vision evaluation.

 

assistive technology to help low vision

 

Advance Spectacle or Head-mounted Magnifiers

This type of low vision assistive device combines the increased magnification of microscopic view lenses, and a specialized head apparatus for securing the lenses before your eyes. This may be a useful low vision aid for hobbies, reading, and other close-up visual tasks.

Handheld Magnifiers

Smaller in size, designed to fit comfortably in your hand, the handheld magnifier can be as simple as the traditional magnifying glass and as advance as an electronic low vision magnifier. Models and manufacturers differ on the size, weight, function, and features available, however the electric handheld magnifier is generally designed to be used with ease and provide multiple magnification strengths. This category of low vision assistive devices offers great visual support for individuals with an on-the-go lifestyle.

Portable Electronic Magnifiers

Perhaps among the most versatile (personal to professional life) low vision assistive devices, the portable electronic magnifiers are able to cover a wide variety of tasks. Some portable electronic magnifiers are extremely lightweight and can be used in the home or in the office. These devices are often capable of being positioned in various directions allowing for information across the room to be gathered clearly and displayed on the personal monitor for enhanced viewing. The ability to adjust the camera (responsible for gathering the images or text) may also be self-directed to provide mirror image viewing, helpful when applying make-up or shaving. Beyond the ease of portability and flexibility, some portable electronic magnifiers offer increased option through viewing modes, adding features like contrast, magnification, computer connectivity and more.

Desktop Magnifiers

Desktop magnifiers, also called CCTV (closed circuit television) magnifiers are more stationary magnifiers. Providing some of the highest levels of magnification power (depending on model and manufacturer), viewing mode options, along with other features, makes these desktop low vision assistive devices more than just an aid for reading.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Prefooter

Pre Footer Background – Set the background color of the pre-footer area directly above the footer.


Footer

Footer Background – Set the background color of the footer area at the very bottom of the page.

Footer Text Color – Set the color of the text in the footer.

Footer Nav Font + Color – Set the typeface, font properties, and color of the footer navigation links.

Footer Nav Link (Active) – Set the color of the footer navigation links on hover.

Center Navigation / Info – Choose between left- and center-aligned footer navigation and site info.

Hide Site Info – Hide the site info in the footer.


Blog

Meta Priority – Select whether date or category of a post appear above its title in blog list view.

Hide Entry Author – Don't display the byline of a blog post. Useful for blogs with a single author.

Hide List Entry Footer – Don't display the footer (Comment + Like + Share) in blog list view.


Gallery Styles

Gallery Navigation – Determines the type of gallery image navigation is provided on the page.

Gallery Info Overlay – Select the type of display used for image title and caption.

Gallery Aspect Ratio – Controls the aspect ratio (width:height) for the gallery active slide.

Gallery Arrow Style – Determines the style of the arrows used to cycle through the slides.

Gallery Transitions – select the transition styles used to animate between slides being viewed.

Gallery Show Arrows – choose to use arrows for cycling through slides.

Gallery Auto Crop – choose to auto crop slide images to the selected ratio.

Gallery Autoplay – choose to cycle gallery images automatically without user interaction.

Gallery Loop – Enable a gallery to cycle through to the first slide after the last slide.

Gallery Autoplay Speed –Specify the speed at which the gallery pauses on the active slide.

Gallery Thumbnail Size – Control the height of thumbnail images when used for gallery navigation.

Gallery Arrow Background – Specify the color that is used for the shape of gallery arrows.

Gallery Arrow Color – Specify the color that is used for the arrow itself.

Gallery Circle Color – Specify the color that is used for the circle shape gallery arrows.

Gallery Info Background – Specify the color used in the background of the image title and caption. 


Event Styles

Event Time Format – Toggle between 24 hour or AM/PM for event times.

Event Icons – Enable icons on the address and event time display.

Event Thumbnails – Show an image thumbnail in list view.

Event Thumbnail Size – Control the size (ratio width:height) of the event thumbnail image.

Event Date Label – Enable date overlay on top of event thumbnail.

Event Date Label Time – Include the time of the event with the date overlay.

Event Excerpts – Show optional excerpt text of events on the list view when present.

Event List Date – Show the full event date (day, month, year) of the event on the list view.

Event List Time – Show the time range (start time-end time) of the event on the list view.

Event List Address – Show the event location address when present.

Event iCal/gCal Links – Show links to add events to Apple or Google calendars.

Event Like and Share Buttons – Show Squarespace simple like and share buttons on events.

Event List Compact View – Enable a simple stacked view of events in the list view.

Event Calendar Compact View – Enable a simpler calendar view optimized for smaller areas


Product Styles

Product Background Color – sets the color behind the product image.

Product Overlay Color – sets the color of the overlay when product list titles are set to 'overlay.'

Products Per Row – determines the number of products shown per line on the product list.

Product List Titles – controls the position of the product title on the product list.

Product List Alignment – sets the text alignment of the product title on the product list.

Product Item Size – select an image ratio for the product photo on the product list.

What is Low Vision? The definition of low vision varies. One definition is visual acuity of 20/70 or worse in the better-seeing eye that is not correctable with eyeglasses. Measurement of 20/70 vision means that a person with unimpaired vision can see the chart from 70 feet away, whereas a person with low vision would have to stand closer at 20 feet. Another definition of low vision is uncorrectable vision loss that interferes with one’s daily activities. This definition is useful because often a visit to the low-vision specialist will focus on ways to improve the patient’s independence and quality of life.   The Low-Vision Evaluation A low-vision evaluation focuses less on the specific disease, and more on the impact that the disease and resultant low vision have on the patient. Therefore, the low-vision specialist will ask about your daily activities, overall health and cognition level, as well as aspects of your social history, including whether you live alone or have support from family and friends. The low-vision specialist will also ask whether you are still driving. During the examination, the low-vision specialist will evaluate your distance and reading vision, contrast sensitivity, field of vision, and additional tests. The specialist will also determine how you use your vision. Some patients will need to use other parts of their visual field, not just the central part. This is called “eccentric viewing.” Sometimes training with eccentric viewing can help patients use low-vision devices more effectively.   Helpful Devices Next, the low-vision specialist will work with you to determine whether there are specific devices that can help you accomplish your goals. One important point is that there will not be one device that can help you with all of your tasks, but rather different devices for different activities. Also, magnification devices may not help glaucoma patients who do not yet have central vision loss, which only occurs in very advanced glaucoma. Magnification Full-Field Microscope Glasses For reading, full-field microscope glasses (very strong reading glasses), are useful because they free up hands to hold the reading material and are portable. However, there are some disadvantages, including the need for very good lighting and a limited field of view, such that the reading material may need to be moved in front of the eyes rather than the usual mode of using our eyes to scan the text. This brings up an important point about magnifiers. As the power of the magnification increases, it results in other challenges such as decreased field of view and image movement, which makes it more difficult to learn how to use the device effectively. However, with practice, patients can adapt and benefit from these devices. Stand Magnifiers A stand magnifier is another option for reading. The device sits on the page and the consistency between the lens and the text results in a more stable image than that of a handheld magnifier. The stand magnifier may also have its own lighting, which is beneficial for reading. The disadvantage is that these magnifiers tend to be less portable and require the user to move the magnifier across the text. Handheld Magnifiers Handheld magnifiers are ideal for people without any tremors or weakness, and they are portable and more useful in situations that only require short-term reading, such as reading price tags and menus. Electronic Magnifiers Electronic magnification (closed circuit television, i.e. CCTV, or a video magnifier) has some advantages because it projects a larger field of view on a screen, provides adjustable magnification and contrast modes, and produces no peripheral distortion. However, a major disadvantage is its cost. An alternative to CCTV is electronic readers (e-readers) such as the Kindle or iPad. These devices allow you to adjust the font size and contrast, and have text-to-speech functionality. However, the magnification is not as great as with CCTVs and glare may still be a problem depending on the device. Low- and High-Tech Tips Low Tech Improve lighting with a gooseneck lamp directed at the reading material. Carry a penlight with you at all times. Wear visors when outdoors to help reduce glare, or try yellow clip-on or wraparound yellow or amber sunglasses. Your low-vision specialist can perform a glare evaluation, and before purchasing any sunglasses try them out on a bright sunny day. Move closer to the TV or to the stage during performances. Borrow large-print books from the library. Purchase large-print remote controls, calendars, games, and books. Use rubber bands on certain medications. Put safety pins on blue clothing to separate them from black items. Switch from ball point pens to felt-tipped pens, which are bolder and easier to see. Borrow audio books from the library. Explore talking watches, calculators, and computers. High Tech Download apps that magnify (iRead, iLoupe, Magnify), or help identify the denomination of money (EyeNote). Use voice interfaces such as Siri. Experiment with mapping programs that provide voice-guided directions. Improving Mobility The difficulties with visual acuity, contrast, and field of vision can be very challenging. Some devices that can help with a constricted field of vision include sectoral prisms, which can increase awareness of side vision, very strong lenses, and reverse telescopes. Some of these devices make objects smaller so that more information fits into a small field of vision, but they are limited by the patient’s visual acuity. Your low-vision specialist may also work with certified orientation and mobility specialists who can help with performing a mobility evaluation, or even a home visit to help identify aids for use in the home. Even small changes at home, such as removing cords that are easy to trip on or marking appliance buttons with raised paint, can make a big difference. Psychological Support Vision loss can certainly be frightening but learning how to adapt, with the aid of low-vision specialists, can result in continued independence and a fulfilling life. Here we have focused on tools to help with the physical adaptations, but it is also important to seek the help of a counselor for psychological counseling if needed. There are also patient groups to help those who are coping with low vision that may provide the group support you need. Finally, maintaining a social network and asking for help will enrich your life far more than staying at home, and indeed help maintain your independence and quality of life.

What is Low Vision?

The definition of low vision varies. One definition is visual acuity of 20/70 or worse in the better-seeing eye that is not correctable with eyeglasses. Measurement of 20/70 vision means that a person with unimpaired vision can see the chart from 70 feet away, whereas a person with low vision would have to stand closer at 20 feet. Another definition of low vision is uncorrectable vision loss that interferes with one’s daily activities. This definition is useful because often a visit to the low-vision specialist will focus on ways to improve the patient’s independence and quality of life.

 

The Low-Vision Evaluation

A low-vision evaluation focuses less on the specific disease, and more on the impact that the disease and resultant low vision have on the patient. Therefore, the low-vision specialist will ask about your daily activities, overall health and cognition level, as well as aspects of your social history, including whether you live alone or have support from family and friends. The low-vision specialist will also ask whether you are still driving.

During the examination, the low-vision specialist will evaluate your distance and reading vision, contrast sensitivity, field of vision, and additional tests. The specialist will also determine how you use your vision. Some patients will need to use other parts of their visual field, not just the central part. This is called “eccentric viewing.” Sometimes training with eccentric viewing can help patients use low-vision devices more effectively.

 

Helpful Devices

Next, the low-vision specialist will work with you to determine whether there are specific devices that can help you accomplish your goals. One important point is that there will not be one device that can help you with all of your tasks, but rather different devices for different activities. Also, magnification devices may not help glaucoma patients who do not yet have central vision loss, which only occurs in very advanced glaucoma.

Magnification

Full-Field Microscope Glasses

For reading, full-field microscope glasses (very strong reading glasses), are useful because they free up hands to hold the reading material and are portable. However, there are some disadvantages, including the need for very good lighting and a limited field of view, such that the reading material may need to be moved in front of the eyes rather than the usual mode of using our eyes to scan the text. This brings up an important point about magnifiers. As the power of the magnification increases, it results in other challenges such as decreased field of view and image movement, which makes it more difficult to learn how to use the device effectively. However, with practice, patients can adapt and benefit from these devices.

Stand Magnifiers

A stand magnifier is another option for reading. The device sits on the page and the consistency between the lens and the text results in a more stable image than that of a handheld magnifier. The stand magnifier may also have its own lighting, which is beneficial for reading. The disadvantage is that these magnifiers tend to be less portable and require the user to move the magnifier across the text.

Handheld Magnifiers

Handheld magnifiers are ideal for people without any tremors or weakness, and they are portable and more useful in situations that only require short-term reading, such as reading price tags and menus.

Electronic Magnifiers

Electronic magnification (closed circuit television, i.e. CCTV, or a video magnifier) has some advantages because it projects a larger field of view on a screen, provides adjustable magnification and contrast modes, and produces no peripheral distortion. However, a major disadvantage is its cost. An alternative to CCTV is electronic readers (e-readers) such as the Kindle or iPad. These devices allow you to adjust the font size and contrast, and have text-to-speech functionality. However, the magnification is not as great as with CCTVs and glare may still be a problem depending on the device.

Low- and High-Tech Tips

Low Tech

Improve lighting with a gooseneck lamp directed at the reading material.

Carry a penlight with you at all times.

Wear visors when outdoors to help reduce glare, or try yellow clip-on or wraparound yellow or amber sunglasses. Your low-vision specialist can perform a glare evaluation, and before purchasing any sunglasses try them out on a bright sunny day.

Move closer to the TV or to the stage during performances.

Borrow large-print books from the library.

Purchase large-print remote controls, calendars, games, and books.

Use rubber bands on certain medications.

Put safety pins on blue clothing to separate them from black items.

Switch from ball point pens to felt-tipped pens, which are bolder and easier to see.

Borrow audio books from the library.

Explore talking watches, calculators, and computers.

High Tech

Download apps that magnify (iRead, iLoupe, Magnify), or help identify the denomination of money (EyeNote).

Use voice interfaces such as Siri.

Experiment with mapping programs that provide voice-guided directions.

Improving Mobility

The difficulties with visual acuity, contrast, and field of vision can be very challenging. Some devices that can help with a constricted field of vision include sectoral prisms, which can increase awareness of side vision, very strong lenses, and reverse telescopes. Some of these devices make objects smaller so that more information fits into a small field of vision, but they are limited by the patient’s visual acuity.

Your low-vision specialist may also work with certified orientation and mobility specialists who can help with performing a mobility evaluation, or even a home visit to help identify aids for use in the home. Even small changes at home, such as removing cords that are easy to trip on or marking appliance buttons with raised paint, can make a big difference.

Psychological Support

Vision loss can certainly be frightening but learning how to adapt, with the aid of low-vision specialists, can result in continued independence and a fulfilling life. Here we have focused on tools to help with the physical adaptations, but it is also important to seek the help of a counselor for psychological counseling if needed. There are also patient groups to help those who are coping with low vision that may provide the group support you need. Finally, maintaining a social network and asking for help will enrich your life far more than staying at home, and indeed help maintain your independence and quality of life.