Macular degeneration (MD) is a disease that damages the macula which is the central part of the retina. The macula is responsible for providing the sharp, central vision we need for reading, identifying objects, recognizing faces and even driving. The macula works best in bright light and is also responsible for providing most of our color vision.
Macular degeneration is a leading cause of vision loss in Americans 60 years of age and older and hence is also called Age-Related Macular Degeneration (AMD). There are two types—dry and wet. In Dry Age-Related Macular Degeneration the retina tissues atrophy slowly over time. In Wet AMD vessels beneath the retina begin to grow and leak that can cause a sudden and potentially dramatic reduction in vision.
There are many other types of disorders that can be called “macular degeneration” including Juvenile Macular Degeneration (Stargardt’s Disease), Macular holes, Best’s Disease, and Epiretinal membranes (Macular pucker). There are also numerous other disorders that can also affect central vision including Albinism, Achromatopsia, Diabetes, MS, Optic Atrophy, Nystagmus, Micro-ophthalmia, Coloboma, Rod-Cone Dystrophy, and Myopic degeneration to name just a few.
Fortunately, macular degeneration is limited to the central retina, so that the peripheral retina, responsible for side (peripheral) vision and motion detection remains intact. Individuals with Age-Related Macular Degeneration will never go totally blind. In fact, individuals can usually walk and engage in most domestic activities with little difficulty due to their vision.
Why don’t regular eyeglasses help macular degeneration?
When macular degeneration damages central vision detail vision its reduced, making print and signs difficult to read and faces difficult to identify. While at first one might assume that an eyeglass prescription may need to be changed, it’s not the eye’s focus that is the problem. It’s the retina, the “screen” at the back of the eye that receives the image and converts it into neural impulses, that’s not working properly.
Imagine visiting a movie theater and seeing the picture perfectly well. Now imagine that black paint is spread across all of one of the actor’s faces. Will changing the focus get rid of the black paint? Of course not. Now imagine that the camera zooms in for a close-up and now the actor’s face is 4 times larger. Now the black paint will cover just the actor’s nose, or cheek or eye, and as a result much more of the face becomes visible. So, what helps individuals with macular degeneration see better is making things larger, and for seeing at a distance, bioptic telescopes can offer a great visual solution.
Telescopic options for low vision
As discussed above, patients complain that they cannot see far enough away to perform whatever activity they have in mind. They must move closer in order to see it adequately. Of course, we may not always be able to move cose enough. That’s where telescopic low vision aids become so important. They bring thing closer optically without the user having to move closer.
Low vision bioptic telescopes can either be positioned above the user’s line of sight so that they can alternate their view between the carrier lens and the telescope (Bioptic), or in a straight-ahead position for convenient use at closer distances.
In either event, attaching telescopic lenses to eyeglass frames makes magnified vision easy and convenient to use!