Robby,
Carnosine or NAC work for some people, but in others, they make the cataract worse. That's because although carnosine is a glycation inhibitor (prevents sugars from latching onto your eye lens proteins), it also - in the presence of copper and zinc ions - prevents your natural eye lens cleanser molecule, glutathione, from photobleaching the pigments that latch onto your eye lens proteins. If (yellow or brown) aging pigments in your eye lens are bleached, they are partially decomposed, and will release the eye lens proteins which got shackled up with them.
Ironically, copper and zinc ions enhance the chaperone activity of alpha-crystallin. That's good in early cataract when there is still some free alpha-crystallin left, and that in turn will help to clear the lens. But in advanced cataract, there ain't no free alpha-crystallin left cos' it's all tied down by other molecules (sugars, and colored pigments). Then, copper and zinc trigger mass aggregation of the other eye lens proteins - beta and gamma crystallins - which creates a really dense cataract. Worse, copper and zinc partially prevent glutathione from photobleaching the pigments. Even worse, if carnosine eye drops are then used, the carnosine finally causes the copper and zinc ions to "completely abolish" the photobleaching action of glutathione. What does that mean? It means carnosine eye drops will make someone with advanced cataract worse, and will color their visual world yellow, red and brown (as it did mine).

Now here's the good news. If EDTA is added to the carnosine, all the photobleaching action of glutathione is restored (research, Kingston University, London, UK). And from there on, the carnosine works synergistically together with EDTA and glutathione to reverse the cataract (yes, even advanced cataract).

It gets better. An eye drop called C-KAD containing carnosine, EDTA and MSM in de- Ionized Water has already been trialed on cataract, including advanced nuclear cataract, back in 2002. In an advanced cataract patient, within about 2 months, his cataract symptoms regressed and his visual acuity shot up. After 1 year, the grade of his cataract fell from 4+ to 3. A Phase II clinical trial of C-KAD was carried out on 80 patients at 4 centers across the US again in 2009, but no results have ever been posted (check for yourself online). Passing strange? The company that developed C-KAD, Chakshu Research, then changed its name to Livionex, abandoned the eye drops, and switched to making toothpaste. Passing strange?

I'm already semi-blind from colored nuclear cataract, and I sure would like some C-KAD. However, it isn't so easy. The EDTA must be ophthalmic grade, not food grade. EDTA is made from toxic raw materials, and may also contain traces of toxic formaldehyde - unless it is EDTA for ophthalmic use. The other two ingredients, L-carnosine and MSM, can however easily be sourced in high purity. Anybody got any ideas? Where do we go from here?