General Differences Between Polarized and Absorptive Lenses

Polarized and Absorptive Lenses

Polarized and Absorptive Lenses
Polarized lenses can be helpful in reducing glare; in fact, they were first developed to help with glare from outdoor sports and activities. Here is a passage from All About Vision that explains the basics of polarized lenses very well.

Light reflected from surfaces such as a flat road or smooth water generally is horizontally polarized. This means that, instead of light being scattered in all directions in more usual ways, reflected light generally travels in a more horizontally oriented direction. This creates an annoying and sometimes dangerous intensity of light that we experience as glare. Polarized lenses contain a special filter that blocks this type of intense reflected light, reducing glare.

Though polarized sunglasses improve comfort and visibility, you will encounter some instances when these lenses may not be advisable. One example is downhill skiing, where you don’t want to block light reflecting off icy patches because this alerts skiers to hazards they are approaching. In addition, polarized lenses may reduce the visibility of images produced by liquid crystal displays (LCDs) or light-emitting diode displays (LEDs) found on the dashboards of some cars or in other places such as the digital screens on automatic teller machines and self-service gas pumps. With polarized lenses, you also may be unable to see your cell phone or GPS device.

Boaters and pilots also have reported similar problems when viewing LCD displays on instrument panels, which can be a crucial issue when it comes to making split-second decisions based strictly on information displayed on a panel. (Some manufacturers of these devices have changed their products to solve the problem, but many have not yet done so.) Many polarized lenses are available in combination with other features that can enhance outdoor experiences.

Absorptive Sunlenses/Sunglasses do a little more than just reduce glare.

These are special wraparound sunglasses that filter out ultraviolet (UV) and infrared (IR) light. I explained those two types of light in my post. In addition to reducing glare, they can also increase contrast, which is important for visibility.

They also come in a variety of tints: dark gray-green, medium amber, medium gray, medium plum, yellow, orange, amber, and light orange. Many of the available tints/colors also have a percentage sign. The percentage sign represents the amount/percent of visible light that is transmitted through the lens. Here are some examples:

  • 32% medium gray
  • 10% medium amber
  • 2% dark gray-green
  • 20% medium plum
  • 65% yellow
  • 49% orange
  • 16% amber
  • 52% light orange

It is the tint – in combination with the amount of light transmission of each tint – that is helpful for people with glare issues. There are a few manufacturer websites that explain the range of absorptive lenses very well.

The first is NoIR Medical Technologies (NoIR stands for “No Infra-red” light.) You’ll see that there are different colors and tints, and many of the colors also have a percentage sign. The percentage sign represents the amount/percent of visible light transmitted through the lens.

Generally, NoIR recommends the following for people with glare problems:

  • 32% Grey
  • 13% Dark Grey
  • 18% Grey
  • 40% Grey-Green
  • 20% Plum
  • 16% Amber
  • 10% Amber
  • 54% Yellow

You can see from the list that the color does not have to be extremely dark for the lenses to reduce glare and light sensitivity.

Also, Eschenback Optik provides a good overview of Solar Shields, another type of absorptive lens product.

Most styles of absorptive lenses also can be fitted over prescription lenses. The bottom line is that it’s probably necessary to visit an office that carries a supply of these lenses and determine which color, tint, and percentage of light transmission is right for your wife. It’s helpful to compare several styles to determine what tint and percentage of light transmission work best.

10/27/15


Maureen Duffy, CVRTMaureen A. Duffy, CVRT, LVT
Social Media Specialist, visionaware.org
Associate Editor, Journal of Visual Impairment & Blindness
Adjunct Faculty, Salus University/College of Education and Rehabilitation

Low Vision Resources

What to do when “There’s nothing more that can be done.”

“I’m sorry, but there’s nothing more that can be done. There is no cure for your eye condition.”

In your work as healthcare professionals and health educators, it’s likely you’ve encountered a significant number of adults and older adults who have been on the receiving end of this devastating news.

When an eye care provider says, “There’s nothing more that can be done,” what he or she likely means is, “There’s nothing more I can do for you surgically.” But instead of saying, “There’s nothing more that I can do,” the discouraging message delivered to the patient is, “There’s nothing more that can be done.”

Thus, in many cases, the discussion ends there. Patients will either exhaust their resources searching for an elusive cure or become resigned to a life that is restricted and defined by incurable vision loss.

When receiving a diagnosis of vision loss, many adults who have managed to overcome a host of obstacles in their lives may now believe they are facing an obstacle with no viable solution. A natural, and understandable, initial reaction is to focus instead on the devastating losses that are seen as an inevitable accompaniment to blindness and low vision such as:

  • Loss of independence: “How will I prepare meals, clean my home, or shop? Will I become a burden to my family and friends?” 
  • Loss of confidence and self-worth: “All my life I’ve been physically active and self-reliant. Has my life as an independent person come to an end?” 
  • Loss of privacy: “I won’t be able to handle my finances independently. Will I have to surrender control of my life to someone else?” 
  • Loss of employment: “I’ll have to quit my job. How will I earn a living?” 

It’s important to let your clients and patients know that there is indeed hope—and life—after vision loss. A wide range of vision rehabilitation services enable adults who are blind or have low vision to continue living independently. The term “vision rehabilitation” includes highly trained professionals and comprehensive services that can restore function after vision loss, just as physical therapy restores function after a stroke or other injury.

Patient working with a low vision therapist
Patient working with a low vision therapist

Vision rehabilitation professionals include:

Additional vision rehabilitation services can include:

  • Peer support and counseling: talking with peers, sharing common concerns and frustrations, and finding solutions to vision-related problems. 
  • Vocational rehabilitation: vocational evaluation and training, job training, job modification and restructuring, and job placement. 
  • Veterans’ services: vision rehabilitation and related support services for blinded veterans of all ages. 

There are many resources available to help your patients and clients locate vision rehabilitation services. For example, the VisionAware Directory of Services allows you to browse by state and type of service, including counseling resources, support groups, low vision services, independent living skills, and orientation and mobility. The VisionAware “Getting Started” Kit provides tip sheets on specialized services and products that can assist with everyday life after vision loss.

The National Eye Institute’s National Eye Health Education Program (NEHEP) also has low vision education resources. The video, Living with Low Vision: Stories of Hope and Independence, explains how, as a health professional, you can help your patients make the most of their remaining vision and improve their quality of life by referring them for vision rehabilitation services. Share it with your colleagues, too. You can find additional resources and ideas for promoting vision rehabilitation on the NEHEP Low Vision Program page.

 

Maureen Duffy, CVRTMaureen A. Duffy, CVRT
Social Media Specialist, visionaware.org
Associate Editor, Journal of Visual Impairment & Blindness
Adjunct Faculty, Salus University/College of Education and Rehabilitation