Astaxanthin is anticipated to improve vision by enhancing blood circulation in the eye also reducing free radicals.
Numerous illnesses, including brain and heart ischemia, reperfusion injury following such ischemic events, and tumor growth, involve oxidation processes [62, 63]. As a result, cutting-edge research on antioxidant compounds has intensified. In the realm of ophthalmology, antioxidant therapies have been studied since oxidation has been linked to diseases such age-related macular degeneration (AMD), diabetic retinopathy, uveitis, and cataracts [64, 69].
Visual display terminals (VDTs), like PCs, smartphones, pads and TVs are widely used and essential in modern life. However, it is known that VDT use results in a reduction in blink frequency, dryness of the eye from insufficient blinks, impaired accommodative function, headache, and tense shoulders [66]. In addition, the proportion of people who have subjective physical symptoms such stiff shoulders and eye tiredness rises as the duration of VDT operation does. Light emitting diodes (LEDs) make up the majority of VDT light sources, and exposure to their blue light is thought to cause dry eyes and eye discomfort by producing reactive oxygen species (ROS) in photoreceptor cells over time [73].
As a result, astaxanthin is anticipated to restore ciliary body function by enhancing blood circulation also reduce free radicals which will enhance accommodative function, improve acuity and contrast sensitivity, lessen eye fatigue.
Substation studies focused on astaxanthin benefits on eye health:
Yasunori Nagaki et al. (2002). “Effects of astaxanthin on accommodation, critical flicker fusion, and pattern visual evoked potential in visual display terminal workers.” J.Trad.Med.19, 170-173, 2002.
“We evaluated the effects of astaxanthin, a red carotenoid, on accommodation, critical flicker fusion (CFF), and pattern visual evoked potential (PVEP) in visual display terminal (VDT) workers. As controls, 13 non-VDT workers received no supplementation (Group A). Twenty-six VDT workers were randomized into 2 groups: Group B consisted of 13 subjects who received oral astaxanthin, 5 mg/day, for 4 weeks, and Group C consisted of 13 subjects who received an oral placebo, 5 mg/day, for 4 weeks. No significant difference in age was noted among the 3 groups. A double-masked study was designed in Groups B and C. Accommodation aqilitude in Group A was 3.72±1.5 diopters. Accommodation amplitudes (2.3±1.4 and 2.2±1.0 diopters) in Groups B and C before supplementation were significantiy (p<0.05) lower than in Group A. Accommodation amplitude (2.82±1.6 diopters) in Group B after astaxanthin treatment was significantly (p<0.01) larger than before supplementation, while accommodation amplitude (2.32±1.1 diopters) in Group C after placebo supplementation was unchanged. The CFFs and amplitude and latency of P100 in PVEP in Group A were 45.0±4.2 Hz, 6.54±1.8 μV, and 101.3±6.5 msec, respectively. The CFFs in Groups B and C before supplementation were significantly (p<0.05) lower than in Group A. The CCFs in Groups B and C did not change after supplementation. Amplitudes and latencies of P100 in PVEP in Groups B and C before supplementation were similar to those in Group A and did not change after supplementation. Findings of the present study indicated that accommodation amplitude improved after astaxanthin supplementation in VDT workers.”
YASUNORI Nagaki et al. (2005). “The effect of astaxanthin on retinal capillary blood flow in normal volunteers.” Transl. J. Clin. Ther. Med., Vol. 21 (Issue 5) (2005). [66]
“We evaluated the effect of astaxanthin on retinal circulation in healthy volunteers. Design: A double blind randomized placebo controlled study. Methods : Thirty-six volunteers were randomized into two groups: An astaxanthin group that consisted of 18 subjects who received oral astaxanthin, 6mg/day, for 4 weeks and a placebo group that consisted of 18 subjects who received an identical looking oral placebo for 4 weeks. Retinal capillary blood flow was measured using a Heidelberg Retina Flowmeter. Changes inblood pressure, blood cell counts, fasting plasma glucose level, fasting plasma astaxanthin level, retinal capillary blood flow and intraocular pressure were examined and a survey about eye strain taken before and after supplementation in both groups. Results : The fasting plasma astaxanthin level in the astaxanthin group was significantly (p<0.001) higher than before supplementation. The fasting plasma astaxanthin level in the placebo group after placebo treatment remained unchanged. After 4 weeks supplementation, retinal capillary blood flow in the astaxanthin group was significantly (p<0.01) higher than before supplementation in both eyes, while retinal capillary blood flow in the placebo group after placebo treatment was unchanged. Intraocular pressures in both groups remained unchanged during thesupplementation period. Conclusion: Our results suggest that astaxanthin supplementation may increase retinal capillary blood flow.”
Y. Nagaki et al. (2011). “Effect of Astaxanthin on Accommodation and Asthenopia.” J. Clin. Ther.Med., 22 (1) (2011), pp. 41-54.
“To investigate the effects of astaxanthin (AX) on accommodation and subjective asthenopia. Subjects and Methods: The subjects were patients who had been occupationally engaged in work requiring the use of a visual display terminal (VDT) for 6 h or more per day for more than 1 year and who frequently experienced asthenopia. They were recruited and provided informed consent. For objective assessment of the clinical trials, we employed a double-blind placebo controlled design where the results of the dietary supplements (AX) group were compared with those of the control (placebo) group. After consumption of AX for 4 weeks, an evaluation was made on the pre-and post-treatment accommodation ability, and the patients were asked to complete a questionnaire to report their subjective asthenopia. In parallel, the safety of astaxanthin was assessed through a clinical examination and a doctor’s questionnaire Results: (1) The post-treatment accommodation ability of the AX group with respect to value and rate of change was significantly higher than that of the control group. (2) The distribution of rate of change also showed significant improvement in post-treatment accommodation ability of the AX group when compared to control group. (3) Subjective questionnaire regarding 4 conditions (“eyestrain”, “hazy vision”, “flickering images”, “my shoulders/back feel stiff”), showed that AX group significantly improved to those of control group. (4) Clinical examinations revealed no clinically relevant abnormal changes resulting from AX consumption. Furthermore, there were no reports of adverse events associated with AX consumption. Conclusion: Here we demonstrated that AX consumption (9 mg per day) for 4 weeks substantially alleviated symptoms associated with accommodation ability and subjective asthenopia. Moreover, no safety problems associated with AX consumption were found.”
Saito et al. (2012). “Astaxanthin increases choroidal blood flow velocity.” Graefes Arch Clin Exp Ophthalmol 250(2): 239-245.
“Previous studies have reported that astaxanthin (AXT) has antioxidative and anti-inflammatory effects in addition to its ability to shorten blood transit times. As laser speckle flowgraphy (LSFG) can noninvasively visualize the hemodynamics of the choroidal circulation, we used the technique to evaluate whether continuous ingestion of 12 mg of AXT per day could increase quantitative blood flow velocity. METHODS: In this randomized, double-blind, placebo-controlled study, we examined 20 healthy volunteers who ingested 12 mg AXT or placebo capsules over a 4-week period. LSFG was measured in the right eyes of all subjects at pre-ingestion, and at 2 and 4 weeks after the treatment of AXT. LSFG values were used to calculate the square blur rate (SBR), which is a quantitative index of relative blood flow velocity. RESULTS: A significant increase of the macular SBR was seen 4 weeks after AXT ingestion when compared to the pre-ingestion values (Wilcoxon signed-rank test, P = 0.018). In contrast, no statistical difference in the macular SBR was detected in the placebo group (Friedman test, P = 0.598). No subjective or objective adverse events were found after the 12-mg AXT ingestion. CONCLUSIONS: Results suggest that administration of AXT over a 4-week period can elevate the choroidal blood flow velocity without any adverse effects.”
Hashimoto et al. (2016). “The effect of astaxanthin on vascular endothelial growth factor (VEGF) levels and peroxidation reactions in the aqueous humor.” J Clin Biochem Nutr 59(1): 10-15.
“We explored the effect of astaxanthin on vascular endothelial growth factor in the aqueous humor, by measuring vascular endothelial growth factor levels and oxidation-related parameters, including O2 (*-) scavenging activity, H2O2 level, and total hydroperoxide level in the aqueous humor, obtained from 35 patients before and after astaxanthin administration. We evaluated the relationship between vascular endothelial growth factor and the oxidation-related parameters as well as the patient’s diabetic status,age, and sex. Vascular endothelial growth factor levels did not change significantly but O2 (*-) scavenging activity and total hydroperoxide level significantly (p<0.05) increased and decreased, respectively. Both pre- and post- astaxanthin intake, vascular endothelial growth factor and total hydroperoxide levels were positively correlated (Pearson: r = 0.42, p<0.05; r = 0.55, p<0.01, respectively). Analysis of vascular endothelial growth factor levels and O2 (*-) scavenging activities gave a negative correlation but only pre-astaxanthin intake (r = -0.37, p<0.05). Differences in levels pre- and post-astaxanthin only showed association between vascular endothelial growth factor and total hydroperoxide (r = 0.49, p<0.01) analyzed by multiple linear regression. Using multivariate analysis, pre-astaxanthin vascular endothelial growth factor level was associated with two factors of total hydroperoxide and O2 (*-) scavenging activity (r = 0.49, p<0.05), and post-astaxanthin vascular endothelial growth factor level with two factors of total hydroperoxide and sex (r = 0.60, p<0.01). Astaxanthin intake may have affected vascular endothelial growth factor level through its antioxidant effects by increasing O2 (*-) scavenging activity and suppressing peroxide production.”
Hashimoto et al. (2013). “Effects of astaxanthin on antioxidation in human aqueous humor.” J Clin Biochem Nutr 53(1): 1-7.
“We evaluated the antioxidative effects of astaxanthin through the changes in superoxide scavenging activity, levels of hydrogen peroxide and total hydroperoxides in human aqueous humor. The study subjects were 35 patients who underwent bilateral cataract surgery on one side before and the other side after intake of astaxanthin (6 mg/day for 2 weeks). Their aqueous humor was taken during the surgery and subjected to measurements of the three parameters. After astaxanthin intake, the superoxide scavenging activity was significantly (p<0.05) elevated, while the level of total hydroperoxides was significantly (p<0.05) lowered. There was a significant negative correlation between the superoxide scavenging activity and the level of total hydroperoxides (r = -0.485, p<0.01), but no correlations between the hydrogen peroxide level and the other two parameters. Astaxanthin intake clearly enhanced the superoxide scavenging activity and suppressed the total hydroperoxides production in human aqueous humor, indicating the possibility that astaxanthin has suppressive effects on various oxidative stress-related diseases.”
Supporting studies on astaxanthin and eye health:
After ingestion of astaxanthin for consecutive 28 days, the uncorrected far visual acuity significantly improved in groups receiving 4 mg or 12 mg. The accommodation time significantly shortened in groups receiving 4 mg or 12 mg. There was no change in refraction, flicker fusion frequency, or pupillary reflex. Study mentioned in “Additional studies” section.
The symptoms eye fatigue, eye heaviness, blurred vision and eye dryness in P group were increased, but Ax group showed increased in eye fatigue and eye heaviness. On the basis of these results, we concluded that astaxanthin has the effects of reducing and preventing eyestrain induced by accommodative dysfunction. Study mentioned in “Additional studies” section.
We have examined the effects of AX on accommodative recovery from rest after operation. Ten healthy volunteers participated in the study. One subject was removed from the study as that person developed allergic conjunctivitis during the study. Therefore, only nine volunteers were evaluated (9 dominant eyes) based the objective diopter value, the HFC value, and the accommodative reaction value. The result showed the HFC value after operation decreased significantly after AX intake compared to that of before uptake. This study suggested that AX had effect on accommodation and worked on accommodative fatigue during the recovery process, which aided in relieving fatigue rapidly. Study mentioned in “Additional studies” section.
6-weeks consumption of the test food inhibited a decrease in the accommodative function caused by visual display terminal operation (UMIN000036989). Study is presented in “Combinatorial applications of astaxanthin” section.
Oral antioxidant supplementations may increase tear production and improve tear film stability by reducing tear ROS. The vegetable-based antioxidant supplement used in this study is safe and can be utilized as an adjuvant therapy to conventional artificial tear therapy for patients with dry eye syndrome. Study is presented in “Combinatorial applications of astaxanthin” section.
In nonadvanced age-related macular degeneration eyes, a selective dysfunction in the central retina (0 degrees -5 degrees ) can be improved by the supplementation with carotenoids and antioxidants. No functional changes are present in the more peripheral (5 degrees -20 degrees) retinal areas. Study is presented in “Combinatorial applications of astaxanthin” section.
Patients treated with lutein/zeaxanthin and astaxanthin together with other nutrients were more likely to report clinically meaningful stabilization/improvements in visual acuity, contrast sensitivity, and visual function through 24 months compared with nontreated subjects. Further studies are needed with more patients and for longer periods of time. Study is presented in “Combinatorial applications of astaxanthin” section.
This study shows that multiple dietary supplement containing lutein, astaxanthin, cyanidin-3-glucoside, and DHA has effect to improve accommodative ability and subjective symptoms related to eye fatigue. Study is presented in “Combinatorial applications of astaxanthin” section.
The study reported improvement of visual acuity and muscle fatigue after dietary supplementation with astaxanthin.
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66. YASUNORI Nagaki et al. (2005). “The effect of astaxanthin on retinal capillary blood flow in normal volunteers.” Transl. J. Clin. Ther. Med., Vol. 21 (Issue 5) (2005).
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Algalif, Natural Astaxanthin: Human Clinical Studies Overview
