15 Feb. 2007
SETI League
PriUPS Project

A Valuable Safety Tip

Your life is important to me.  For the next 60 seconds I'm going to deliver information that may preserve you as a reader of this blog.  I think I'm up to 10,000 millireaders and so can't spare any! 

This tip has to do with gravity and bifocals.  I've mentioned it several times elsewhere, but a moment of panic followed by a quick search revealed that I had not written about it here, and I feel it would be important to enough to "interrupt this blog" if, in fact, the blog were not already discontinuous.  You know how I'm always telling you to "Be careful" (and occasionally to "Be lucky")?*  I'll admit that sometimes both can be futile suggestions, but this time I have something specific.

As one ages, the ability of the eyes to focus or "accommodate" diminishes.  A frequent concomitant is the need to wear not just glasses, but glasses with distinct regions of correction.  For example, while driving, you need to focus on the road and while reading you need to focus on your computer screen (or "book").  Instead of switching glasses, you can use either "progressive lenses" which blend different regions together seamlessly, or bifocals, which have two sections separated by a distinct line.  (Trifocals exist, too, and this blogitem probably applies to them as well, although I've never actually used them.)

When wearing bifocals, one semi-consciously uses the far or near section depending on one's current need.  A neck-angle adjustment and proper pointing of the eyes is all that is necessary.  But for the activity of climbing and particularly descending a staircase, this doesn't seem to work.  Rather, I have found that if I look at a staircase as I climb or descend, the demarcation line between the different refractive sections of the bifocals often falls on the boundary between stairs and can appear to swallow one of them up.  This would not be a major issue if it weren't for gravity.  It turns out that placing a foot on a nonexistent stair can result in damage to the body to which the foot is attached.  As goofy as this sounds, I have found a handful of references to this on the internet, so it has been at least noticed by others, some of whom survived.

Avoiding Bifoculargenic Damage

I wouldn't be me if I didn't have the solution for this problem.  (You can trust me, at least for now, as I am physically undamaged despite using stairs on a daily basis.)  In fact there are several solutions:

The best may be to use "progressive" lenses.  When I first tried them, I found them somewhat disorienting, but after about an hour I became accustomed to them.  If you gave up after an initial try, go back!  I use these everywhere but at home, and since they employ no abrupt refractive transition, there's no problem.

I do use bifocals at home, and only at home, because I read a lot, and I find the larger area of correction more convenient.  Because I have a limited number of staircases at home, I counted and memorized the number of actual steps on each one, a number which has so far remained invariant with time.  This is no great prodigy of memorization.  I simply have to remember which has seven and which has eight.  I'm up to the challenge as long as I don't have to read any CNN articles about my house.  ("Mr. Factor climbs 8,000 stairs five hundred times every day...")  By not looking down and counting the steps as I walk up or down assures that I will use only steps that are there, and none that aren't.  At least I will on days when I'm not having attention span problems.  Sometimes, when I'm feeling especially frisky, I'll even close my eyes while varying my elevation.

An extra added safety plus:  I hold on to the railing while climbing and descending.  I paid for it and I might as well use it.

Home Accidents

Remember, some large percentage of accidents occur in the home.  I'd know that percentage if I were to look it up, or be able to tell you that it's 754% if I could find that CNN article again.  Please don't have one of those accidents.  I'd hate to have 1,000 of my millireaders damaged.

* With a modest effort I could have strung five punctuation marks together there, but I didn't want to stretch my luck.

NP:  "If I Needed Someone" - Street

Richard Factor

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