After wearing glasses for thirty-odd years, I’m tired of it. I’m thinking of surgery; since I’m on the verge of needing bifocals, my bright idea is to have one eye adjusted for distance and the other for arm’s length (the typical distance of a computer screen or a gun sight). It did occur to me that this might be a Bad Idea for some reason I hadn’t thought of, so I decided to bring it up with my optometrist. To my surprise, as soon as I mentioned LASIK he brought up monovision. He pointed out that some people find it very hard to adjust, and suggested that it would be wise to try it with contacts first before risking anything permanent.

So now I have contacts; temporarily accepting a lot more optical fuss in the hope that later I’ll have much less. With them, my dominant eye is (according to Doc Lowe) about 3/4 diopter more farsighted then than my, er, submissive eye. (Presumably there is a term of art but I don’t know what it is.) I think his plan is to increase the difference every few weeks.

I haven’t got the knack of taking soft contacts out. With hard ones, you just put tension on the lids and pop!. These I have to drag out with a fingertip. Today and yesterday I stripped one eye on the first try, but had a much harder time with the dominant eye – which is counterintuitive; you’d think the thicker lens would be easier to grab.

Entirely unrelated: In The Atlantic, an article on the rationale of the naked streets movement (though it doesn’t use that phrase). The key point: when rules take the place of judgement, people learn not to use judgement. A similar argument has been made about safety regulation in general.

Forgive my waxing hyperbolic . . .

This is a tiling of the hyperbolic plane by triangles whose angles are π/2, π/3, π/7 – the smallest possible tile. I present it in a conformal mapping analogous to the Mercator projection, which I’ve never seen done before.

Some years ago, using basic theorems of hyperbolic trigonometry, I worked out a conformal representation of the hyperbolic plane which preserves one line – analogous to the Mercator projection of the sphere, a conformal map which preserves one great circle. (At that time, I had a mistaken notion of the Mercator rule, so I didn’t know until later how strong the analogy is.) Unfortunately I’ve utterly forgotten how I worked it out; and I need to try again; because, now that I’ve learned enough hyperbolic analytic geometry to try making some pictures, there appears to be a flaw in my formula.