halacha - Do you have to be able to see to do shechita?

In the wake of a question about shechita on a boat (ok, with a cutlass, but also on a boat), the topic of other unusual shechita conditions came up in chat:

Can I do it in on a boat? Can I do it on a goat?
Can I do it in the rain? Can I do it on a train?
In the dark? In a tree?
In a car? Shecht, you see? ...
- Charles Koppelman

This got me wondering -- can you do shechita in the dark? Can a blind man be a shochet?

My instinct is "no" because it seems like you would need to visually verify your work, but I'm a city-dweller for whom meat comes in portioned packages wrapped in styrofoam and plastic wrap. I've never witnessed nor studied shechita. I've heard that it's largely done by feel and being able to see doesn't actually matter.

So: does halacha permit sightless shechita? And if it does, is it actually practical to do?

Answer

Simla Chadasha (the book on shechita) rules (11:1) that one should not shecht in the dark/at night, because he won't be able to look at the simanim, to check whether he did what he needed to do (רוב אחד בעוף רוב שנים בבהמה; most of one "siman" (windpipe/foodpipe) for a bird, most of two "simanim" for an animal). "Dark" is defined as "too dark to see what he's doing," so it will be a little subjective.

However, if one did so, and is able to check the simanim afterwards, then the shechita will always be kosher, even if it was done in the dark, or at night-time.
Interestingly, Mateh Asher there (#3) notes that someone who needs glasses to see is also not allowed to slaughter if he's not wearing his glasses -- the above rule doesn't have to do with daytime, or a certain amount of light that is present; it has to do with the ability to see. If someone is unable to check the simanim after shechita without his glasses on, then he can't shecht without his glasses.
Another point to note, Mateh Asher also says (#8) that if someone is using an electric lamp ("נר עלעקטר"י"), he needs to have a back up candle, because "פעמים נכבה מעצמו ע"י סבה," "sometimes it will go out for whatever reason." However, my rebbi has noted that there is no longer a need for this, as our electric lights are pretty reliable; as far as I've seen, we don't require a back up candle when shechting at night by electric light, though I've been told that some groups of chasidim are still concerned for this. I have shechted at night by electric light without a candle under my rebbi's supervision.

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About the blind: Simla Chadasha rules (1:37) that someone who is blind "in both eyes" may do shechita, although it should not be done lechatchila, unless there is someone else observing, or there is a pressing need (שעת הדחק is the same as בדיעבד).
If the particular person is a "מובהק בדעת ויראת ה," and knows the halacha very well, then he can be trusted to check his own shechita, to determine if the shechita was done properly.