Yes, you heard it! I said eye drops.
The information is as hot as the bread coming out of the oven: published less than a month ago, but perhaps on its way to revolutionizing vitamin A supplementation. Having in mind the quietly-installed vitamin A hypervitaminosis and risks associated with its hepatotoxicity, it is no wonder that one day a researcher thought: “Wait a minute! If dry eyes are the problem, then drop it in the eye!“.
And so they did…
A research group from the Department of Ophtalmology, Juntendo University Shizuoko Hospital led by Toshida et al. dared the adventurous – but high reward – path of direct delivery straight to the eye. An ophtalmic solution containing 500IU/mL of retinol palmitate was tested for its safety and efficacy in treating dry eye among patients with a confirmed dry eye diagnosis. The rigorously controlled study enrolled 66 patients, all were 15 years or older, that were randomized to receive either vitamin A (retinol) or placebo.
A multicenter, placebo-controlled, randomized, double-masked, parallel-group Phase II clinical study – Drug Design, Development and Therapy 2017:11
The authors assessed the presence of subjective symptoms – such as dryness, eye fatigue, foreign body sensation, blurred vision, eye pain, photophobia, heaviness, itching, ocular discomfort, eye discharge, tearing, and hyperemia – before and after receiving the eye drops. The vitamin A group showed an improvement for all the symptoms, except hyperemia (eye redness).
“No serious drug-related adverse events occurred in any patient during the study.“- Drug Design, Development and Therapy 2017:11
That’s why I think science, and pharmacy in particular, is fabulous! The active vitamin A, so-called retinol, has to be preformed first by cutting beta-carotene, then it has to be transported to the liver, stored there for ages (400+ days is the half-life time), and EVENTUALLY 1 out of every 100 molecules or so gets transported to the eye to prevent occurrence of dry eyes. Unfortunately, the transport of retinol to the eye is not as efficient as the vitamin A storage in the liver. The more we eat or supplement, the more stays in the liver. Indeed, a little more makes it to the eye, but – let’s be honest: good eye sight without a properly working liver isn’t what you had in mind when starting to take vitamin A!
So now, here we are witnessing a discovery in the making: Toshida et al. have shown that vitamin A eye drops can be considered safe and efficacious. Does this mean that you should go buy liquid vitamin A and drop it in your eye? NOOOOO! DO NOT DO THAT! Not all liquid forms of vitamin A can be used as eye drops. Specifically, only one can – the one we just learned about this summer. Eye drops are very special liquids or gels. They must be free of any germs and preservatives. Above everything else, depending on where you are in the world, they must have been approved by a drug agency responsible for the drug safety in the area where you are. For the United States, the Food and Drug Administration is – of course – the agency in charge.
When will we see the vitamin A eye drops prescribed or available? Hard to predict, but let’s give a forecast: I say under 5 years. Is it long? Short? Given the fact that the above clinical study just demonstrated its safety, one would become optimistic. But I learned to be reserved in these matters. I look forward to a bigger phase III/IV clinical study that will establish effectiveness and safety in a bigger randomized trial implemented for a longer time. I also hope to see how the patients from the current study will do in the months and years following this experience. No, I do not expect that anyone will grow wings or orange hair, but I want to make sure that all the bases are covered if I am to ever make a recommendation to use or not to use vitamin A eye drops!
Hope you enjoyed the news. Stay in good health till next time!
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Wait for the FDA…. id rather watch turtles race