All I can say is after years of working with optics the idea makes me shudder with revulsion...

You want a solvent that is pure and will not leave a residue- windex does not fit the bill...

Windex-like products typically contain detergents, ammonia, fragrance to moderate the odor of ammonia, and some form of dye. The original modern Windex was colored a light, transparent shade of blue, but varieties are marketed today in a variety of colors and fragrances, touting additives such as vinegar or lemon juice.
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The Sam Wise patent #3,463,735 lists several example formulae, one of which is 4.0% isopropyl alcohol (a highly volatile solvent) 1% ethylene glycol monobutyl ether (a less volatile solvent), 0.1% Sodium laurel sulfate (a surfactant), 0.01 tetrasodium pyrophosphate (a water softener), 0.05% of 28% Ammonia (added more for smell than for cleaning ability), 1% of a dye solution, and 0.01% perfume. This formula was not only significantly less expensive to manufacture, but allowed the product to be packaged in glass bottles and dispensed with a plastic sprayer.

The product was recently reformulated [1] to more environmentally-desirable solvents. Reducing solvent levels paradoxically results in cleaner glass because the glass cleaner does not evaporate as quickly, and the consumer must polish the glass longer.

From Wikipedia

I have no idea how such additives would affect the coating on my optics... but since it would require wiping the surface to get them off it is unacceptable...