Cineraria eyedrops containing an extract of the plant "cineraria maritima" (alternative name: Dusty Miller) are available from homeopathy stores in the US. There seem to be two versions, one is Dr. Reckeweg and the other one is Schwabe. They are manufactured either in India or Germany, but if they are sold in the US, there will be no problem regarding sterility.
I do not know whether they would improve an advanced nuclear cataract with dense colored pigments (AGEs) at the core of the lens. But there seems to be no harm in trying them.