Low Vision – When Glasses aren’t Enough

Low Vision – When Glasses aren’t Enough

 

There are many diseases that can affect the back of the eye, the retina, and cause permanent vision loss that cannot be fixed with glasses.  Conditions such as macular degeneration and diabetic retinopathy (from diabetes) can devastate a person’s vision leaving them unable to read, write, watch TV, pay bills, drive, and many other activities that sighted individuals do every day without thinking about how their lives would be different if they could not see.

Why won’t glasses work?  The example I give my low vision patients is an analogy of the old cameras that used real film.  “The job of glasses is to focus light onto the retina, the same way the lens of a camera focuses light onto the film.  If a disease has damaged the retina, then there are no glasses that will help, just like if there is damage to the film there is no camera lens that will focus to make a good picture.”

 If there are no glasses, medications, or surgeries to fix the back of the eye then what choices are there?  Some optometrists offer low vision services which uses different devices to help low vision individuals use their REMAINING eyesight more efficiently.  We are NOT restoring vision, merely training what is left to work better.  There are three issues that must be addressed:

1.)    Contrast.  This is the difference between an object and the background around it.  The eye chart at the doctor’s office is HIGH contrast, black letters on a white background.  Human faces are considered LOW contrast.  The nose, ears, cheeks, chin are all fleshy colored and tend to blend together making faces appear to be blobs instead of well-defined individual structures.  To address the loss of contrast, we must have GOOD lighting (strong light directly on the reading material) and use filters to block certain wavelengths of light and enhancing others. 

2.)    Magnification.  When areas of the retina are damaged from disease, the images must be made larger to hit the “healthy parts” of the retina.  The amount of magnification differs depending on how bad the vision is.  We work exclusively with PRESCRIPTION MAGNIFIERS which are high quality devices that reduce the distortion and enhance images.  There are literally thousands of devices that can be used to enlarge images and it takes someone who has studied in low vision to help you choose the right device and the right power.

3.)    Learning to do things differently.  Many patient’s that suffer from low vision are elderly and have been doing things the same way their whole lives.  When explaining their condition and the possible options it is important that they understand that in order to see they may need change how they read, use different devices based on the situation, or where in the house they read. 

When different diseases damage the retina and a loss of vision follows, doctors specializing in low vision must look at contrast, magnification, and new ways to use vision in order to help the patient return to a more normal life.  Lighting, devices (filters and prescription magnifiers), and training can truly help a person with vision loss get back to performing their activities of daily living and give back the independence that has been lost.

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