Eye Fatigue (2002-2009 Studies) Reducing with Astaxanthin
A study looking at the effects of nutrients on lifestyle-related eye problems (such as macular degeneration, aggravated by the blue light from electronic devices) pointed out that astaxanthin is one of the carotenoids that are valuable in reducing inflammation that causes such conditions (Ishida, 2009).
Iwasaki & Tawara (2006) also confirmed the same tendencies of subjective eye fatigue complaints in a randomized double-blind placebo controlled double-crossover study.
Furthermore, questionnaire results obtained by Shiratori et al., (2005) and Nagaki et al., (2006), also confirmed the previous findings that astaxanthin supplementation at 6 mg for 4 weeks improved symptoms associated with tiredness, soreness, dryness and blurry vision.
A study by Takahashi & Kajita (2005), also demonstrated that astaxanthin attenuates induced-eye fatigue, as opposed to treating eye fatigue, which suggests prevention rather than treatment. Astaxanthin treated groups (asthenopia negative) were able to recover quicker than the control group after heavy visual stimulus.
2004A study by Nakamura (2004), demonstrated significant improvements in reducing asthenopia and positive accommodation for the 4 mg (p<0.05) and 12 mg (p<0.01) groups. However, it was not until Nitta et al., (2005), who established the optimum daily dose at 6 mg (n=10) for a period of 4 weeks by comparing eye fatigue using a visual analogue scale (VAS) based questionnaire and accommodation values. Overall, the 6 mg group improved significantly better at week 2 and 4 of the test period.
A study by Nagaki, 2002, demonstrated that subjects (n=13) who received 5 mg astaxanthin per day for one month showed a 54% reduction of eye fatigue complaints.
In a sports vision study (Sawaki, 2002), researchers demonstrated that depth perception and critical flicker fusion had improved by 46% and 5% respectively on a daily dose of 6 mg (n=9). The effect of astaxanthin on visual performance prompted a number of other clinical studies to evaluate the optimum dose and identify the mechanism of action.
Nagaki, Y, Hayasaka, S, Yamada, T, Hayasaka, Y, Sanada, M, et al. (2002). Effects of astaxanthin on accommodation, critical flicker fusions, and pattern evoked potential in visual display terminal workers. J Trad Med, 19(5):170-173.
Nakamura, A., Isobe, R., Otaka, Y., Abematsu, Y., Nakata, D., et al. (2004). Changes in Visual Function Following Peroral Astaxanthin. Japan J Clin Opthal, 58(6):1051-1054.
Takahashi, N., Kajita, M. (2005). Effects of astaxanthin on accommodative recovery. J Clin Therap Med, 21(4):431-436.
Ishida, S., (2009). Lifestyle-related diseases and anti-aging ophthalmology: suppression of retinal and choroidal pathologies by inhibiting renin-angiotensin system and inflammation. Nippon Ganka Gakkai Zasshi, Mar;113(3):403-22
Sawaki, K., et al. (2002). Sports performance benefits from taking natural astaxanthin characterized by visual acuity and muscle fatigue improvement in humans. J Clin Ther Med, 18(9):1085-1100.