Since a bleeding pineal tumor left me with diplopia (double vision, in my case owing to a neurological injury in the alignment of my eyes) in January 1996, I've hoped that one day I would be able to use both eyes again to fuse my right and left images into one. For over ten years of nothing happening in that direction, I put tape over my right spectacle lens and used only my left eye for focused seeing, though a cataract was beginning to cloud the light. After surgery to remove the cataract (and install a lens that all but removed the left eye's near-sightedness), I didn't have to use tape anymore; my right image was so fuzzy (through spectacles with the same thin, left-eye prescription in both lenses) that my brain pretty much ignored it anyway.
But then, last year, my new neuro-ophthalmologist proposed that a prism in one of my spectacle lenses could render my two images close enough for the brain to fuse them. His professional enthusiasm for the project matched my personal hope. He proposed an experiment to try to prove this. I'd be fitted for a soft contact lens for my right eye that would approximately equalize its image in size with my left eye's image, and I'd wear a temporary prism patch on one of my spectacle lens for a month. It worked; I was able to fuse.
The next step, then, was to have cataract surgery in the right eye too. It happened that the optimum lens the surgeon installed resulted not only in unrefracted 20-20 vision in that eye, but also in the complete removal of that eye's astigmatism. (The earlier cataract surgery has reduced the left eye's astigmatism, but not entirely removed it; its astigmatism must have been caused by a combination of surface imperfections, some in the original, natural lens and some in the cornea, which hadn't been affected by the surgery. Apparently the right eye's astigmatism had been owing entirely to the imperfection of its original lens.)
I "adjusted" to the cataract surgery for a month or so, still using the temporary prism patch, then a permanent prism was ground into the right lens of my glasses (both the ones for long distance and the ones for reading). I could now use both eyes for fused-image driving, movie watching, and so on, as well as for reading and "office work" (most of it involving a computer screen).
Not quite. I soon noticed that I couldn't read a book for more than a few minutes before my eyes seemed to rebel, and I begin to see two lines of text, one more or less horizontal, the other slanting in at about five degrees from the upper right. Fusing was just too much of a strain to do for long. (I already knew this from a pin-hole experiment of my own I had conducted in the years right after the brain surgery. I must have wanted so badly lately to fuse again—regularly, day in and day out—that I wouldn't let myself remember how much of a strain it had been and might continue to be.)
Working at a computer with both eyes was proving even less successful than reading a book or magazine. I could fuse, with considerable effort, for a few seconds only, before the two images flew apart and I had to favor one eye (virtually always my preferred, left eye) for looking at words or pictures. Making only the mightiest effort, could I get the eyes back together for a few more seconds of fusing. Without realizing it (or putting two and two together), I ended days at the office exhausted and was falling asleep on the commute ride home virtually every evening.
My eye doctor suggested that I do some "pencil push-ups" to strengthen the eye muscles that "crossed" the eyes for close-up. Bring the pencil end towards my eyes slowly, then take it away, and again and again, thirty times or more a day for a month. The push-ups did make a difference. I could now read a book for much longer before noticing the rebellion, but I saw hardly any improvement at the computer. We tried the exercises for another month. No more improvement.
Okay, my doctor said, the prism you have aids fusing in the vertical dimension. We could put a horizontal prism into the other lens of your reading spectacles. It needs to be slightly under-strength, so that you don't become dependent on it and your eye muscles lazy.
I've had my new reading glasses for a week. Reading a book is great, but in some ways computer work has become even worse. The horizontal prism makes it possible for me to fuse longer looking at the screen. The fact that I can do it more readily now encourages me to try harder (a conscious effort) to achieve it. The attempt is painful, and I can make it for only a little while before I want to scream.
So. The "truth" that I think I have discovered today (through the suggestion of my wife, who proposed it and pointed out that I myself hadn't given a thought to this possibility) is that my recent almost chronic fatigue could be owing entirely (if it turns out I have no sleep apnea whatsoever) to "brain drain."
I went to my primary care physician last November with my first complaints of being continually tired. Only today did it occur to me that that was but a few weeks after the experiment described above, my second cataract surgery, the vertical prism, my new glasses...and the apparently regained world of image-fusing....
Whether this "theory" is true or not, and whether the sleep study results will identify a sleep disorder or not, I believe, right now, that my wife may have discovered to me the primary reason I have been so tired lately. Curiously, this "truth" (whether it be true or not) gives me hope, even energizes me—I don't feel so tired right now. I don't need for my physician to call me today; I can wait until next week to be told the results of the sleep study.
Before sitting down to write this, I stuck a piece of tape over my right spectacle lens, as of old.
The hope that I will use both eyes fully again might have been dashed, but the hope that my energy level will rise again is revived.
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