February 06, 2008
This afternoon, after two weeks of anticipation, I picked up my new glasses. The frames and lens shape and size fit my face perfectly. Both Sibylle and I are very pleased with how they look. Unfortunately i am finding it hard to see through them.
Because I needed astigmatism correction as well as help with my near vision, my lenses are progressive, or “no line,” bi-focals. Little did I know when I agreed to this style of lens what I was getting myself into. When I first put them on I was delighted to suddenly have near focus again. The sample text at the fitting desk, which I could only read at arm’s length, was clear and crisp through the glasses. I was too giddy with the sensation to notice that the progression in the lens, from top to bottom, and from the outside edges inward, caused significant distortion of the periphery of my corrected vision.
After I got home and started using the glasses to work on the computer I immediately noticed some odd visual artifacts. The area of greatest magnification in the lens is tiny, perhaps only as wide as the tip of my forefinger. Reading a sentence, whether on screen or in a book, requires that I turn my head - I have to continually move the spot of focus along the line. As I turn my head the area of vision defined by the outer rim of the lens distorts, wripples like someone was twisting the screen or book. Imagine the funhouse mirror and you’ll have an idea what I am seeing evertime I turn my head.
I called my Dad to see if he had progressive lenses in his glasses. Nope. Just old fashioned tri-focals, complete with lines. Next I called Ted, who it turns out, does have progessive lenses. Has had for nearly a year and is “still getting used to them.” He takes them off to read (not an option for me) and is considering getting lined bi-focals on his next trip to the optomitrist. Not encouraging.
Sibylle did some web searches and together we found several articles about the challenges of adapting to progressive lenses, including this one. All indicated that it could take two or three weeks for the wearer to adapt. They also indicated that great care had to be taken in selecting the right type of progressive lenses, based on the wearer’s activities. Heavy computer use or reading would require a different lens structure than non-hevy use might.
Finally I got out my old lined-bi-focals and wore them to see if the fun-house mirror problem existed there as well, and I had forgotten about it. No distortion whatsoever. Tomorrow I am going to return to the vision center and initiate an exchange to get lined bi-focals. Spending as much as 10 or 12 hours a day using a computer or reading will be miserable if I have to wear glasses that make me dizzy when I turn my head.