Some really good advice from
all the other posters on this thread....
I would add to my own post a couple of comments.
1. If you have certain visual problems by all means use whatever sight options or modifications are available to enhance your shooting...
2. The Crimson Trace option would seem to fit your home defense needs perfectly. They're wonderful for close range and they enable a person to get on the target quickly once the firearm is sighted in. They shine in dim light or dark conditions but are almost useless in bright sunlight beyond about ten yards.
3. The beauty of the Crimson Trace produce is you can retain your original factory open sights and use them too, plus have the grips installed "laser" sighting instantly available for darker light conditions...
A draw back for many people is the retail cost of their product. Some models are in the $300 dollar range.
Another plus for this option is women who shoot infrequently love them. These sights gives them confidence to see where (or hope where) their bullet will be hitting. That make it an easy sell to wives especially...
Hope this helps...