Vitamin A – how important is it in treating – or causing – dry eye?
Vitamin A – how important is it in treating – or causing – dry eye?
As a senior resident in Ophthalmology, I was tasked to oversee the junior residents in their daily clinic. One day a bright junior resident approached me with the case of what was subsequently dubbed, “the peanut kid.” As this was close to 4-decades ago, the details should be hazy – but the important pieces remain clear as it was a true glimpse into a severe vitamin A deficiency the likes of which would rarely be seen outside of a third world country.
This approximately 13-year-old child had been seen by several city-wide eye doctors with the complaint of severely dry and irritated eyes. He’d been prescribed a variety of steroid and combination steroid and antibiotic eye drops, ointments, and artificial tears without relief. By the time he got to the resident’s clinic, his mother was upset and fortunately remained tirelessly committed to getting her son appropriate treatment. At the time of exam, he had “glassy eyes” that were glazing over with a roughened corneal surface, including some dry, triangular patches on the outer part of the eyeball (what this resident recognized as “Bitot Spots”).
Astutely, this resident asked the mother if there was anything unusual about her son’s diet. The amazing answer was something like this – “You’re the first doctor to ask about his diet and I’ve been reluctant to bring this up, but yes – he is quite unusual in that he only seems to like peanuts.” Subsequent inquiry determined that he would eat a bag of peanuts for breakfast, another for lunch and then two for supper. He would have “Hi-C” – an orange flavored drink rich in vitamin C, with breakfast and sometimes have ice cream after supper. These foods would provide the vitamins C and D along with calcium in the ice cream – and peanuts are a surprisingly good source of other vitamins, proteins, fats and minerals – so the remaining weak link in his dietary chain (apart from some essential Omega Oils) was Vitamin A.
Of further interest was the mother’s recall that as a younger child, when he first developed this peculiar interest in a peanut diet, his pediatrician told her that it would be a passing phase, and that she could keep him on a healthy track by supplying a (then Flintstones brand) child’s daily vitamin. At some point, around the time his pediatrician passed away, he stopped taking the vitamins and the new pediatrician seemed disinterested in her child’s diet. His health otherwise appeared “normal” so the idea this would be a passing phase caused her to go along with her son’s peculiar diet.
Further testing revealed he was almost totally night blind (an expected side effect of Vitamin A deficiency, as this vitamin is critical in supplying the retinal pigments responsible for vision in general – though night vision is typically the first to notably suffer). Lab work revealed an essentially undetectable level of Vitamin A in his bloodstream. The good news was that he responded quickly to vitamin A supplements, recovering his night vision, and restoring a healthy ocular surface.
Much research has been done in determining the benefits of Vitamin A in ocular health in general and in dry eye disease, in particular. My general sense is that short of an exceptional diet like the “peanut kid,” it is unlikely we will find many patients truly deficient in Vitamin A in the developed world – but as children get increasingly “picky” (and appear to subsist on diets based on pastries, chicken nuggets, mac and cheese and the like) – I find many who are deficient in essential Omega Oils (& believe a vitamin deficiency is not impossible).
I recently posted on Vitamin A products being touted for dry eye patients, thanks to the brilliant response by Dr. Peter Pham. I’ll paste that conversation here for those who want a deeper dive:
I’ll post her question and the excellent answer from Dr. Peter Pham (a chemist and ophthalmologist who invented the Zocuwipe and Zocugel products):
“Can someone please explain which forms of vitamin A are safe for meibomian glands…? I’m intrigued by the iVizia wipes and HyloNight ung, but hesitate to recommend after years of discouraging use of retinol on lids… any insight is greatly appreciated - thank you! “
Peter Pham: “Agree, am confused about retinoids myself. Such a complex topic with numerous patents and PhDs awarded on this topic, but the general rules of chemistry still apply. We shouldn't look at just one ingredient to determine whether a product is "safe" or "unsafe". This is especially true for "retinol", which comes in many forms. The most biologically active form is the carboxylic acid form, retinoic acid, which is two oxidation steps from the alcohol "retinol" form. Retinoids have multiple unsaturated isoprene chains and are inherently unstable. Just because a product has 1% or 0.1% retinol does not mean there's actually that much available since multiple other variables are involved from co-ingredients to packaging (airless bottles better than jars) to pH to temperature storage/fluctuations. If a retinol product is stored or transported at high temperatures or exposed to light, there may little useful retinol left, no matter what the initial percentage was. If a product is mostly water without much oil or emulsifiers, it's unlikely to be able to dissolve much retinol, which is oil soluble and we can predict that the percentage of retinol would be low. iVizia and Hylo both use the more stable ester form of retinol but what's not apparent from the ingredient list is that even the ester form needs to be stabilized, usually with the antioxidants butylated hydroxytoluene (BHT) or butylated hydroxyanisole (BHA) in the source product. There's an endless stream of superficial, fear-mongering posts about how BHT and BHA are "dirty" ingredients, with "retinols" mixed in there. But the mere presence of an ingredient does not make anything unhealthy or dirty. If a chemical is serving a useful purpose, it's unlikely to cause harm. Retinol helps to maintain ocular health - we know what happens when we lack it. And there's no doubt high doses of oral retinoic derivatives over a prolonged period can kill meibomian glands. As with everything, too much or too little of anything is never good.”
I’m not sure I know either. It does seem to vary by each case and may depend on the product and how it’s applied. Best to consult your dry eye specialist to get the best answer. Orally, eating plenty of leafy greens and colorful vegetables is the best source, as your body will convert these lutein and xeazanthein nutrients into active forms of Vitamin A as your body needs them. Too much active A can damage your liver, so unless you’re diagnosed as low, you generally don’t want to take the active form of Vitamin A in high quantities. Topically, your specialist can monitor the health of your eyes on appropriate supplements if they feel they are necessary.
To schedule an appointment with Dr. Jaccoma, call Excellent Vision at either of these two dry eye offices:
(1) 155 Griffin Rd, Portsmouth, NH 03801 (603) 574-2020
(2) 3 Woodland Rd, STE 112 Stoneham, MA 02180 (near Boston) (781) 321-6463
(Last week’s post includes an index to past posts which will not include this post but is otherwise a complete reference!)