Figure 6summarizes the pattern trends for the analyzed ages, genotypes, and treatments. NND analysis revealed consistently regular patterns in wild-type animals, an increasing tendency toward random patterns with age in
syu t4+/− and
syu tbx+/− retinas, and predominantly random patterns in the dorsal retinas of
alb zebrafish subjected to light toxicity, both before and after a period of regeneration
(Fig. 6A) . The shift from predominantly regular to random patterns was statistically significant (
P < 0.05) between young and old
syu +/− retinas of both genotypes and between any two of the three conditions for the
alb retinas. Quadrat analysis revealed consistently regular patterns in wild-type animals, tendencies toward both randomness and clumping in
syu t4+/− and the regenerated dorsal
alb retinas, and tendencies toward randomness in the dorsal
alb retinas immediately after acute light toxicity
(Fig. 6B) . The reduction in proportions of the analyzed regions showing long-range regularity was statistically significant (
P < 0.05) between any two of the four conditions for the
syu +/− retinas, and between control and light-treated
alb retinas. The increase in proportions of analyzed regions showing blue cone clumping was statistically significant (
P < 0.05) between young and old
syu t4+/− retinas and between regenerated and nonregenerated
alb retinas. Planimetric density of blue cones did not change significantly with age in either wild-type or
syu t4+/− retinas
(Fig. 6C) . The density of blue cones decreased significantly however, compared with the control after light-induced damage (
P < 0.05) and then increased significantly after regeneration (
P < 0.05;
Fig. 6C ). These results are consistent with a regenerative response that has not fully resolved the native local or global pattern of blue cones.