Abstract
Purpose :
Monochromatic lights coexist with high or low temporal flicker provide different defocus signals to control eye growth. We want to know how the dopamine system changes during this process and whether it is related to refraction changes.
Methods :
Guinea pigs were randomly divided into eleven groups. Sixty animals were raised in White-steady, White-0.5Hz, White-20Hz groups. Eighty animals were raised in White-steady, Green-steady, Green-0.5Hz and Green-20Hz groups. Eighty animals were raised in White-steady, Blue-steady, Blue-0.5Hz and Blue-20Hz groups. Refraction were measured by streak retinoscopy at week 8. Changes in retinal dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in vitreous were determined by high pressure liquid chromatography with electrochemical detection (HPLC-ECD).
Results :
Refraction in Green-0.5Hz showed myopia and Blue-0.5Hz showed hyperopia, which were very similar to Green-steady and Blue-steady. Blue-20Hz showed less hyperopia compared with Blue-steady and more hyperopia in Green-20Hz than Green-steady. DOPAC significantly decreased in White-20Hz compared with White-steady. Both DA and DOPAC decreased in Green-steady compared with White-steady. DA and DOPAC increased in Green-0.5Hz compared to Green-steady. No significant difference was found between Green-steady and Green-20Hz. DA increased in Blue-steady compared with White-steady. DA decreased in Blue-20Hz compared to Blue-steady. However, DOPAC were not higher in Blue-steady compared with White-steady. DOPAC decreased in Blue-20Hz compared to Blue-steady as well.
Conclusions :
Monochromatic light affect the synthesis and secretion of dopamine. Flickering light at different frequencies stimulate dopamine differently compared with steady light. Changes in dopamine may not be responsible for changes of refraction in monochromatic lights coexist with high or low temporal frequency.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.