  We reanalyse optical gravitational lens surveys from the literature in order
to determine relative probabilities in the $\lambda_{0}$-$\Omega_{0}$ plane,
using a softened singular isothermal sphere lens model. In addition, we examine
a portion of the $\lambda_{0}$-$\Omega_{0}$ plane which includes all viable
cosmological models; this is vital for comparison with other cosmological
tests. The results are, within the errors, consistent with those of more
specialised analyses, such as those concerning upper limits on $\lambda_{0}$ in
a flat universe. We note that gravitational lensing statistics can provide a
quite robust LOWER limit on the cosmological constant as well, which could
prove important in confirming current claims of a positive cosmological
constant. At 95% confidence, our lower and upper limits on
$\lambda_{0}-\Omega_{0}$, using lens statistics information alone, are
respectively -3.17 and 0.3. For a flat universe, these correspond to lower and
upper limits on $\lambda_{0}$ of respectively -1.09 and 0.65.
