A polymerizable composition is described, which composition comprises a
major amount of a polyol(allyl carbonate) monomer, e.g., diethylene
glycol bis(allyl carbonate) monomer, and a minor amount of a radically
polymerizable second monomer represented by the general formula,
##STR00001## wherein R.sub.2 is a polyvalent linking group that is free
of urethane linkages, e.g., R.sub.2 may be a residue of a polyisocyanate,
such as isophorone diisocyanate; R.sub.3 is a residue of a material
having a single hydroxy group and at least one allyl group, R.sub.3 being
free of urethane linkages, e.g., R.sub.3 may be a residue of a
poly(alkylene glycol) allyl ether, such as poly(1,2-propylene glycol)
allyl ether; and j is a number from 2 to 4. The second monomer may also
be present in the composition in an amount at least sufficient such that
a polymerizate, e.g., a plus ophthalmic lens, obtained from the
composition is substantially free of tinting defects, e.g., ferns and/or
moons.