Effect of zinc on the visual sensitivity of the bullfrog's eye

Mineral elements in the hair of amblyopic children

Amblyopia is a common cause of vision damage in children, and some aspects of its etiology are not clear. A number of mineral elements have important effects on the nerve and visual nerve systems. However, little is known about the relationship between amblyopia and nutritional mineral elements. In this study, hair samples were collected from 67 children with amblyopia and 57 age-matched control groups. The height and weight of each child was measured, and body mass index (BMI) was calculated. Mineral elements were determined by atomic absorption spectrometry and inductively coupled plasma-atomic emission spectrometry. The calcium and magnesium levels in the hair of amblyopic children were higher (p < 0.006), but the level of manganese were lower compared with those in the control groups (p < 0.006). Other elements measured were found to have an insignificant difference between the two groups (p > 0.006). The BMI of amblyopic children was higher (p < 0.001). These results show that mineral elements may play an important role in the visual development of children. Therefore, studies should pay more attention to investigating the impact of mineral elements on child vision.

Dietary supplementation: effects on visual performance and occurrence of AMD and cataracts

OBJECTIVE

To evaluate results of studies that have provided information regarding the effects of dietary supplementation on visual performance, development and progression of age-related macular degeneration (AMD), and risk for cataracts.

RESEARCH DESIGN AND METHODS

Studies with information about the effects of dietary supplementation were identified via PubMed searches that combined (in separate searches) the terms 'supplement' OR 'supplementation' OR 'diet' AND 'cataract' or 'macular degeneration' or 'visual' OR 'vision'. Additional references concerned with biologic effects of specific agents, measurement of visual function, and the etiology and epidemiology of cataracts and AMD were identified on the basis of PubMed conventional literature searches.

RESULTS

Studies of the effects of dietary supplementation, primarily with preparations including lutein and zeaxanthin, have demonstrated improvements in contrast sensitivity and visual performance under glare conditions that, in some studies, have been correlated with effects of treatment on macular pigment optical density. Results from both observational and prospective interventional studies generally support the conclusion that dietary supplements including these xanthophylls significantly decrease the occurrence of AMD and the development of nuclear lens opacities. However, there is variability in results regarding effects of dietary supplementation that may be related to limitations of long-term observational or interventional studies and which cannot be easily controlled or which may also be related in some studies to other important, yet unrecorded, diet- and lifestyle-related factors that are capable of influencing the risks for AMD and/or cataracts.

CONCLUSIONS

The multiple benefits of dietary supplementation support the development and use of these preparations to promote optimal visual function and decrease risk for AMD and cataracts. Increasing understanding of the optimal approach to supplementation will depend upon results from interventional studies that also carefully evaluate and analyze well-established factors for these two conditions.