One of the reasons our eyes age is something called glycation. Glycation transforms the "proteoglycan" material our eye and lens are made out of gradually into something resembling cooked meat chemically.
At one point several years ago, my eyes were in really terrible shape, and I thought it was irreversible, but somehow, they have improved. Basically, I take a lot of different antioxidants, and some of them I think make a very big difference. In terms of bang for the buck a good one is alpha lipoic acid. Ideally, you should take a low dose several times a day.
Around that time I was diagnosed with glaucoma too, and I still have it but its dramatically better now.
Another thing that helps the eyes are many so called "phytochemicals". Almost all berries are good for the eyes, and so are those phytochemicals in them. Bilberry extract is known to be very good for night vision. Also ALL of the carotenoids are good for your eyes.. beta carotene, but also astaxanthin and zeaxanthin.
Resveratrol is super good for the eyes. One study I have seen verifies that but I know it from personal experience.
Another thing that is really good for the eyes is L-carnosine, but its expensive. There is a very expensive n-acetylated carnosine that has been patented and is sold as a nonoperative way of reducing cateracts.. However, if you look at the literature, and trace it back, you'll find one paper by the same Russian scientist who patented the n-acetyl carnosine, that reveals that l-carnosine in a very dilute saline solution has similar effects, it just has a very short shelf life. So, you can buy one 50 gram bottle of l-carnosine for around $25 and - making sure to keep it clean, make up small batches of eye drops AS YOU USE THEM, and never keep unused solution for more than two or three days. Also, refrigerate it.
This is also a good treatment for old dogs who often are going blind. Carnosine is the best way to reduce the opacity of the eye!
The body manufactures its own carnosine from histidine and beta-alanine but obviously, the eye is not so heavily vasuclarized so evidently, supplemental carnosine helps a lot. Its also an AGE inhibitor so it helps you get a leg up so to speak on the glycation process which otherwise will eventually kill all of us.