Depends on what your vision problem is. Some are nearsighted, some are farsighted, some just need reading glasses. Along with those variables, some have verying degrees of glaucoma, some have cataracts. You can't just take another old guys recommendations. Oh, and some are color blind or have compromised color recognition with certain colors. See your eye doctor and experiment with some stuff yourself. You can use the opinions on the forum for ideas, but you can't get a definitive answer to your question from "I like x" posts. No offense to anybody her, but those are the facts.
I'm 70 years old and have been shooting for 50 years. For myself, I'm near sighted, wear bifocals and have mild glaucoma. If I use three dot nights sights I see SIX dots in very low light conditions. All of my sights are plain black rear. With night sights, I prefer them on the front only. In dim light at normal civilian defensive distances, I'm just sticking the front sight on the target anyway.
With plain rear sights, I don't think it makes any difference what the color is, since the front sight is just a general reference point. If you are staring intently on your super bright colored front sight instead of the barely visible attacker, you have more of a problem than which color to use.
I think in some cases, there is too much emphasis on equipment rather than technique. For defensive purposes, you should have established the ability to properly index the gun in fast defensive drills. Use of a flash sight picture is the goal. Precision shooting skill is OK too, but the odds are the flash sight picture or just indexing skill is what you will use in low light.
My defensive shooting group will occasionally shoot in near pitch blackness. At seven yards you can get good hits, even without night sights - if you have good indexing. After the first shot you can't see the glow of the sight anyway and are silhoutting the sights on the target. If your range allows it, try it sometime.
I don't claim to be an expert on this, but I can say what my own experiences have been. Take it or leave it.