Re: AGEs

Eyedrop developed by Dr. Robert Rowen.
Let's take a closer look at the ingredients.
Reduced glutathione: This may function to break down the "miniature molecular cages" formed by wasted (oxidized) glutathione in the lens. These "mini-cages" trap colored chromophores (damaged lens crystallins) inside them, and prevent clearance of the cataract by lens enzyme systems. However, the reduced glutathione in the eye drops may also become oxidized, making the situation worse.
DMSO (Dimethyl Sulfoxide): This functions to transport the other two ingredients in the eyedrop through the cornea. However, as it is also an oxidized sulfur compound, it would tend to create an oxidizing environment not conducive to reduction of glutathione.
Vitamin C: Normally, vitamin C functions as a reducing agent to prevent oxidation in the lens. But vitamin C itself is oxidized by the AGEs in the cataractous lens, even in the absence of oxygen, and in this way, vitamin C contributes to formation of more AGEs, again making the situation worse. This oxidation of vitamin C is not prevented by reduced glutathione. Please see the paper by Linetsky et al, at:

http://www.jbc.org/content/289/24/17111.full
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"UVA Light-excited Kynurenines Oxidize Ascorbate and Modify Lens Proteins through the Formation of Advanced Glycation End Products"

Background: Human lens proteins accumulate pigmented, protein-cross-linked AGE adducts during cataract formation, and the mechanisms of their formation are poorly understood.
Results: UVA-excited kynurenines can oxidize ascorbate under anoxic conditions and promote synthesis of AGEs.
Conclusion: UVA light-excited kynurenines promote AGE synthesis and contribute to cataract formation.
Significance: This study provides a mechanism for UVA light-mediated damage to lens proteins during cataract formation".
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Quote from this paper:
"Ortwerth's group identified more than 100 ASC-derived AGEs in cataractous human lens proteins (1), for which the structures are not known. Thus, ASC is a dominant AGE precursor in the human lens".
(ASC=ascorbate=Vitamin C).
Thus, Vitamin C, when it is oxidized by AGEs excited by UV-A light, contributes hugely to cataract formation.
Quote from this paper:
"Oxidation of ASC by photoexcited kynurenines is not prevented by GSH".
(GSH=reduced glutathione).
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Once again, we see that the only possible way to reverse an advanced cataract with an eyedrop is to chemically break the bonds between AGEs and lens proteins, and destroy the AGEs.
We can also appreciate that, to prevent progression of cataract, it is of paramount importance to avoid exposure to UVA light, and even better, block the conversion of the aminoacid tryptophan to kynurenine and other degradation products which do all the damage.
On the Net, I found that curcumin blocks degradation of tryptophan by blocking induction of the enzyme Indoleamine 2,3-Dioxygenase (IDO).
Consuming turmeric on a regular basis could therefore help.
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