New Rare Condition to Add to My Collection: Pellucid Marginal Degeneration

Went to a new eye doctor today.  Turns out I do not have Keratoconus after all.  My left eye has Pellucid Marginal Degeneration, which is often confused with it and is much more rare.  The good news is that it does not lead to blindness and does not get worse with age.

I had been wearing soft contacts for almost twelve years until one day in 1998, my new optometrist gave me the usual eye tests.  Right eye was fine.  Left eye though, not so much.  "Which of these look better, one or two?"  "Neither"  This went on for too long as I sat nervously, wearing those steam-punk goggles.  The doctor seemed very puzzled, then told me "Well it looks like you have Keratoconus, or a curved cornea.  There's not much we can do.  We could give you glasses, but the left lens would be about 5 inches thick.  Sorry."  Wha?!

Luckily, we have an optometrist in the distant family.  Called him, and he said the doc was crazy and recommended another one.  He too declared "Keratoconus" but claimed "your last doc was wrong -- you can do something about it.  Hard contact lenses."  Rigid gas-permeable, to be exact.  They are like tiny translucent blue versions of those saucer sleds kids play with in the snow.  In fact, they are so similar to those that it's very easy to lose them in the sink drain.