Of modern medicine, nutrition, and evolution

This topic has come up a few times over the years in conversation with various people who occasionally glance at this blog:

Are we still evolving? Modern medicine has eliminated many previously lethal hazards. So has evolution come to a stop?

[W]ithout natural selection to weed out problematic mutations, humans won't just stop evolving - we will also start accumulating defective genes. Each of us, says Kondrashov, has around a thousand mutations which we would be better off without. Without natural selection, future generations will have many more. Kondrashov is quick to point out that he is not talking about eugenics, or traits that are of dubious disadvantage. Rather, he is worried that we will build up traits that are clearly a problem - such as mutations that inhibit our ability to process cholesterol in the blood.

Since I, my father, and my brother all have eyesight imperfect enough that we would have been unlikely to survive as primitive hunters or gatherers, the following passage particularly caught my attention:

For early humans, a genetic propensity for poor eyesight would have been disastrous - try gathering food or dodging predators when everything is a blur. Today, poor eyesight may be a nuisance, but thanks to modern technology it is no longer remotely hazardous. Jones admits that dependence on such technology might be dangerous if it failed for some reason in the future....

I'm not about to pre-emptively eliminate myself from the gene pool, though.

Link ripped shamelessly from Arts & Letters Daily.