Astaxanthin in the Treatment of Eye Diseases
Astaxanthin is a powerful antioxidant that is a naturally occurring red carotenoid pigment found in microalgae. Its structural and functional characteristics make it a promising bioactive compound in the prevention and management of a wide range of eye diseases. Confirmed by several human and animal studies there is a growing body of evidence the beneficial effects of astaxanthin in the prevention, treatment and the significant improvement in the outcomes of diabetic retinopathy, age-related macular degeneration, glaucoma and cataracts.
Age Related Macular Degeneration
Age-related macular degeneration is a common eye disease and leading cause of vision loss among adult individuals in developed countries. The macula is the part of the retina responsible for sharp and high-resolution vision and its thinning gradually leads to vision loss and subsequently significantly affects patients’ quality of life and daily productivity.
Astaxanthin provides protection against oxidative stress and patients treated with a combination of lutein/zeaxanthin and astaxanthin over a two-year period were more likely to report a significant improvement in visual acuity, contrast sensitivity and vision-related function
The retina is the innermost, light-sensitive nervous layer of the eye and stands as the most metabolically active tissue in the body, with a constantly high demand for oxygen and an almost continuous exposure to light. Both these conditions cause eye vulnerability to irradiation-initiated oxidative damage and subsequent inflammation.
Dry Eye Diseases
Dry eye disease is characterized by a significant increase of oxidative stress markers, which are responsible for altering epithelial proliferation and differentiation homeostasis.
The ocular surface, and in particular the cornea and conjunctiva, is almost constantly exposed to sunlight, which consists of wavelengths including UV light, known as a causative factor of oxidative stress in biological systems.
Results showed that oral micronutrients supplementation significantly improved tear production and stability while decreased corneal fluorescein staining, thus leading to a significant improvement in both signs and symptoms.
Cataract development causes the natural lens of the eye to become opaque, thus leading to decreased visual acuity. It remains one of the main causes of blindness worldwide and surgery is required to restore vision. Lens proteins normally exist under a soluble phase, and such solubility accounts for transparency. Under certain circumstances, such as ageing, diabetes, steroids use and trauma, proteins leave the soluble phase to form high molecular weight aggregates, which account for the light scattering and opacity of the lens. Oxidative stress seems to play a key role since it causes protein modifications and the strong antioxidative power of astaxanthin could be used to prevent cataract development. Additionally, a recent study showed that astaxanthin supplementation delayed the development and progression of metabolic cataracts by inhibiting oxidative stress.
Astaxanthin has been shown to significantly reduce ganglion cells apoptosis that is responsible for the progression of retinal damage in glaucoma.