Shortsightedness and Vitamin D?
Vitamin D seems to have considerable influence on eye health.
We all have learnt that Vitamin D is important for the bones and prevents rickets, but not many know that this Vitamin plays a considerable role in the welfare of the eye.
This is a concern when there is evidence of a pandemic of Vitamin D deficiency in the UK affecting the whole population. Much has to do with decreased sun exposure – let’s face it, the weather has not been great over the last few years. Also because of the risk of skin cancer more people are appropriately covering up.
“…this Vitamin plays a considerable role in the welfare of the eye.”
It is the skin that is responsible for manufacturing Vitamin D and this process requires exposure to sunlight. Pigmented individuals are more affected and it is estimated that 90% of Asians in the UK are Vitamin D deficient.
Considerable research is being conducted on the role of Vitamin D and there is much to discover. The following findings are based on preliminary laboratory findings:
1. Shortsighted people have lower Vitamin D levels
Shortsighted or myopic people have lower average blood levels of Vitamin D than those who are not shortsighted. The trigger for this study was the observation that children of two shortsighted parents who spent more time outdoors had significantly less chances of developing shortsightedness.
The study authors found lower Vitamin D levels in shortsighted patients compared to those who were not, but no differences in levels.
2. Vitamin D improves corneal epithelial barrier function
The corneal epithelium is the outermost layer of the cornea. The cells have tight junctions which makes the layer impermeable. Problems with this epithelial barrier can result in visual problems and a reason why dry eye causes so much havoc. Could Vitamin D have a role in dry eye? No evidence there yet – we look forward to results of research in this area.
3. Vitamin D products has been found in the tears and inside the eye
Vitamin D bi-products or metabolites have been found in tears as well as the aqueous fluid and Vitreous gel inside the eye. Vitamin D supplementation affects the concentration of these metabolites. It is also thought that the corneal epithelial cells are capable of manufacturing D3 metabolites.
4. Vitamin D reduces inflammation in the eye
“Shortsighted or myobic people have lower average blood levels of Vitamin D than those who are not shortsighted”
Inflammation is where the eye becomes angry (red, swollen and painful). The level of inflammation can be low and grumbling and patients with inflamed eyes often complain of discomfort and being sensitive to light. There are many causes of inflammation and these symptoms require investigation and evaluation by an ophthalmologist. It is interesting that the use of Vitamin D can reduce inflammation and one wonders if those with chronic discomfort might be Vitamin D deficient.
5. Vitamin D improves the vision in ageing eyes
“Treated mice showed significant reductions in retinal inflammation and levels of amyloid beta (Aβ) accumulation, a hallmark of aging. They also had significant reductions in retinal macrophage numbers and marked shifts in their morphology. These changes were reflected in a significant improvement in visual function, revealing that vitamin D(3) is a route to avoiding the pace of age-related visual decline”.
6. How can Vitamin D deficiency be diagnosed?
A simple blood test can establish whether there are low levels of Vitamin D in the body.
7. How can Vitamin D deficiency be treated ?
Vitamin D can be provided as a supplement in tablet form in doses ranging from 1000 IU (international units) to 10,000 IU. Your doctor is in the best position to indicate what levels of supplementation is required if you are deficient.
Invest Ophthalmol Vis Sci. 2011 Sep 21;52(10):7359-64. doi: 10.1167/iovs.11-7605. Vitamin D enhances corneal epithelial barrier function. Yin Z, Pintea V, Lin Y, Hammock BD, Watsky MA.
Yanping Lin, John L. Ubels, Mark P. Schotanus, Zhaohong Yin, Victorina Pintea, Bruce D. Hammock, Mitchell A. Watsky 3 Enhancement of Vitamin D Metabolites in the Eye Following Vitamin D3 Supplementation and UV-B Irradiation. Current eye research, October 2012, Vol. 37, No. 10 , Pages 871-878
Lee V, Rekhi E, Hoh Kam J, Jeffery G. Vitamin D rejuvenates aging eyes by reducing inflammation, clearing amyloid beta and improving visual function. Neurobiol Aging. 2012 Oct;33(10):2382-9. doi: 10.1016/j.neurobiolaging.2011.12.002. Epub 2012 Jan 2.
Donald O. Mutti, OD, PhD and Amanda R. Marks, OD, MS Blood Levels of Vitamin D in Teens and Young Adults with Myopia Optom Vis Sci. 2011 March; 88(3): 377–382.