The pupillary direct light reflex change in New Zealand White rabbits before and after SNP injection. A. The illustration of pupillary direct light reflex in New Zealand White rabbits. B. The sample graphs of pupillary direct light reflex from control group, 0.1 mM SNP injection group, 0.25 mM SNP injection group, and 0.5 mM SNP injection group at day 28 after injection. C. The comparison of rate of pupil size change among control group, 0.1 mM SNP injection group, 0.25 mM SNP injection group and 0.5 mM SNP injection group pre- and 28 days post-injection. The ratio of pupil size in SNP injection groups were significantly larger than control group. ns: no significance. *: P<0.05.