Hi-Viz and Tru-Glo are pretty much the two big players.
Hi-Viz ought to run you about $20-30 depending on which you get.
I prefer tritium, but if "any" light (even a nightlight down the hall) is on, the Hi-Viz will be very visible. My dad wears trifocals and he could see the dot easily. You still need on onboard weapon light, but the fiberoptic isn't too bad.
"And Shepherds we shall be. For thee, my Lord for thee. Power hath descended forth from thy hand, that our feet may swiftly carry out thy command. So we shall flow a river forth to thee and teeming with souls shall it ever be. In nomine Patris, et fili, et Spiritus Sancti. Amen."