Figure 1.

1Spectral power distributions of four lights and increased ocular axial length in juvenile monkeys under different CCT LED lighting during one-year experiment

A: Spectral power distributions of three LEDs with similar spectral profiles. Due to differences in ratio of blue and yellow green light bands in each light, CCT increased with increasing blue light band ratio. CCTs of three groups were 2 883±30 K, 3 803±14 K, and 4 740±13 K, respectively (measured by spectral flicking irradiance meter SFIM-400, Everfine Corporation, Hangzhou, China). B: Spectral power distributions of incandescent lamps (CCT: 2 709±74 K). C: Increased ocular axial length over time under three different LED lighting conditions. Ocular axial growth rate under artificial light with lower CCT (3 000 K; red circles) was significantly smaller than that under light with higher CCT (4 000 K, green circles; 5 000 K, blue circles). Differences in growth rates between two higher CCT conditions were not significant (ns). D: LED 3 000 K group (red circles) showed lowest increase in ocular axial length after one year compared with LED 4 000 K (green circles) and LED 5 000 K groups (blue circles). There was no significant difference in axial length between LED 4 000 K and LED 5 000 K groups. E, F: Effects of conventional incandescent lamp (2 700 K; black circles) and LED with comparable CCT (3 000 K; red circles) on development of ocular axial length in juvenile rhesus macaques. Statistical analysis showed no significant differences in axial growth trends throughout experiment (E) or in ocular axial growth between two groups at end of experiment (F). *:P<0.05; **P<0.01. Data are presented as mean±SEM.