  In recent work, Hill and Paz apply the operator product expansion to forward
doubly virtual Compton scattering. The resulting large-$Q^2$ form of the
amplitude $W_1(0,Q^2)$ is compatible with the one we obtain by extrapolation of
low-$Q^2$ results from a chiral effective field theory, providing support for
our approach. That paper also presents a result for the two-photon contribution
to the Lamb shift in muonic hydrogen that has a much larger uncertainty than in
previous work. We show that this an overestimate arising from the inclusion of
the proton pole term in the subtracted dispersion relation for $W_1$.
