Fast forward to the next evening. I have finished reading Enhancing Visual Performance for People with Central Vision Loss by Susana Chung. It took me a while because since I have been losing my vision my reading speed is slow.
The research Dr. Chung did tells us why. It sheds some light on the rest of this mess, too.
Remember when we talked about eccentric viewing? That is looking at things off-center. It is using the peripheral retina, as opposed to the macula, to do our seeing. I knew the peripheral retina is not specialized for detail like the macula but I found out the finest detail the peripheral retina can see is four times larger (at 10 degrees from center) than what the macula can see.
That means we are sort of using a sledgehammer to do the job of a jeweler’s hammer when we try to use the peripheral retina to read. It is rather a blunt instrument!
I also found out if you are using a part of your retina 20 degrees of arc from your macular to read, you are, on average, reading six times more slowly than people who can still use their maculas! No wonder reading can take forever!
Another problem is eye movement control. Your eyes are made to line up the macula with what you are looking at, not to line up some random chunk of peripheral retina. The macula is sort of the sights on your ‘gun’. it wasn’t made to be held sideways and shot no matter what those gangsta movies suggest. It is not natural.
It is possible to improve reading skill and speed through magnification but that only works to a certain extent. Once print size gets too big, you start to have diminishing returns.
Dr. Chung messed around with several, different variables and really did not find anything that had an effect on reading speed in people with central vision loss until she started to study visual span. Visual span is how much information you can take in. It is sort of how wide your ‘look’ is. Most ‘looks’ that happen at the macula take in between 7 and 11 characters. If you are trying to use your peripheral vision 10 degrees of arc away from the macula your ‘look’ can take in about 5 characters at a time. Do the math. That is about half as much information.
Researchers have discovered there is a relationship between visual span, or how much info you can take in in one look, and reading speed. Increased visual spans should therefore lead to increased reading speeds. Perceptual learning – and another study I found – say it should be possible to train someone to widen his visual span and therefore increase his reading speed.
Revealing the actual way to do this is going to have to wait though. The journal article I have is over 20 pages and my reading is a little slow! ? Catch up with me later.