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The 2019 National Coffee Drinking Trends report showed that 64 percent of people who participated in the survey said they had drunk coffee the previous day, which is interpreted as daily consumption. This was up from 57 percent in 2016, said the report. 

Even though the U.S. population is drinking more coffee than ever, the nation still only ranks 25th overall in per capita consumption. The people of Finland average 3 times as much coffee consumption as people in the U.S.

So what does all this caffeine intake do to our eyes?

The research is rather sparse and the results are mixed.

Here are some major eye topics that have been investigated:

Glaucoma

One study, published in the journal Investigative Ophthalmology and Visual Science, showed that coffee consumption of more than 3 cups per day compared to abstinence from coffee drinking led to an increased risk for a specific type of Glaucoma called Pseudoexfoliation Glaucoma.

Another analysis of several existing studies by Li,M et al demonstrated a tendency to have an increase in eye pressure with caffeine ingestion only for people who were already diagnosed with Glaucoma or Ocular Hypertension, but no effect on people without the disease. A separate study, published by Dove Press, done with the administration of eye drops containing caffeine to 5 volunteers with either Glaucoma or Ocular Hypertension showed that there was no change in the eye pressure with the drops administered 3 times a day over the course of a week.

Summing up the available studies in terms of Glaucoma, the evidence points to maybe a slight increase in Glaucoma risk for people who consume 3 or more cups of coffee a day.

Retinal Disease

A study done at Cornell University showed that an ingredient in coffee called chlorogenic acid (CLA), which is 8 times more concentrated in coffee than caffeine, is a strong antioxidant that may be helpful in warding off degenerative retinal disease like Age Related Macular Degeneration.

The study was done in mice and showed that their retinas did not show oxidative damage when treated with nitric oxide, which creates oxidative stress and free radicals, if they were pretreated with CLA.

Dry Eyes

A study published in the journal Ophthalmology looked at the effect caffeine intake had on the volume of tears on the surface of the eye. In the study, subjects were given capsules with either placebo or caffeine and then had their tear meniscus height measured. The results showed that there was increased tear meniscus height in the participants who were given the caffeine capsules compared to placebo. Increased tear production, which occurred with caffeine, may indicate that coffee consumption might have a beneficial effect on Dry Eye symptoms.

Eyelid Twitching

For years eye doctors have been taught that one of the primary triggers for a feeling of twitching in your eyelid has been too much caffeine ingestion (along with stress, lack of sleep and dry eyes). I have been unable to find anything substantial in the literature to support this teaching. Therefore, I’m going to have to leave this one as maybe, maybe not.

The End Result

Overall, the evidence for the pros and cons of coffee consumption and its effects on your eyes appear to be rather neutral. There are one or two issues that may increase your risk for glaucoma but it also may decrease your risk of macular degeneration or dry eyes.

Since there is no overwhelming positive or negative data, our recommendation is--and this holds for most things--enjoy your coffee in moderation.

Related links

• Study: Coffee is good for your eyes
• Study links caffeinated coffee to vision loss
• Effect of caffeine on intraocular pressure
• Effect of caffeine in patients with primary open angle glaucoma
• Drinking coffee prevents eye damage
• Caffeine increases tear volume

Article contributed by Dr. Brian Wnorowski, M.D.

Hydroxychloroquine (Plaquenil) was originally used to treat malaria and is now used mostly to treat rheumatological and dermatological diseases. Its most frequent use now is for rheumatoid arthritis (RA) and Lupus and is often very effective in mitigating the joint and arthritic symptoms these diseases can cause.

One of the most significant side effects of the drug is its possibility of causing eye problems resulting in blurred or decreased vision. The most common issue is damage to the retina. It can impair your color vision or damage the retinal cells, particularly in the area right around the central vision.

In your retina, the area that you use to look straight at an object is called the fovea. The fovea is the area that provides you with the most definition when looking at an object. The area just around the fovea is called the macula and it has the ability to see objects with slightly less definition than the fovea but significantly better than the rest of your retina, which accounts for your peripheral vision. The most commonplace for Hydroxychloroquine to cause a problem is in a ring of the macula surrounding the fovea.

The reason it is important to detect any of these changes as early as possible is that in many instances the changes are not reversible even if you come off the medication.

The risk of this happening is highly correlated with the cumulative dose of the drug you have received. So, the higher the dose and the longer you have been on it the higher your risk.

The current recommendation is a daily dose that does not exceed 6.5 mg/kg/day (that is milligrams per kilograms per day).  There are approximately 2.2 pounds. in a kilogram.  The pills come in 200 mg tablets.  Most people who are on this drug are on either 200 mg once a day or 200 mg twice a day. The safety breakpoint comes at around 135 pounds. People weighing more than that will stay within the safety guidelines (not more than 6.5mg/kg/day) at 400mg per day, but people under 135 pounds should probably only be taking 200 mg per day.

Other risk factors for Hydroxychloroquine retinal toxicity include kidney or liver disease and obesity. Obesity is a risk factor because the drug does not penetrate fat tissue so there is more of the drug in your lean body mass (including your retina and its supporting cells called the retinal pigment epithelium). What that means in real terms is that if you take two people who each weigh 140 pounds and put them both on 400 mg a day and one person is 4-foot 11 and the other is 5-foot 9, the 4-foot 11-inch person is at greater risk for side effects because the shorter person has more of their body weight in fat tissue. Since the hydroxychloroquine can’t penetrate the fat tissue that means there is a higher concentration of it in sensitive tissues like the retina.  People with kidney and liver problems have a tougher time eliminating the drug from their system so they are at higher risk because the body is going to retain more of the drug for a longer period of time.

The recommendation is to have a baseline eye exam with dilation and a visual field test before or soon after starting the drug. A repeat of that exam should occur every year if there is no evidence of toxicity.  

The actual incidence of retinal toxicity from hydroxychloroquine is difficult to pin down because there is usually a long time between being started on the drug and the start of any identifiable retinal toxicity. The overall rate of probable retinal toxicity is in the range of 1 of every 200 people treated. The rate is much lower than that in the first 7 years of treatment but gets to about 5 times higher after 7 years of treatment. Some of that data is old now and there is much greater awareness currently about keeping people below that 6.5 mg/kg/day dosage level.

I have been in practice for over 25 years and have seen “probable” retinal toxicity from hydroxychloroquine a total of 5 times and only once in the last 10 years when people have been more careful about keeping the dosage in the right range.

The drug can be very effective in its treatment of RA and Lupus and the likelihood of serious vision problems is small and can potentially be avoided with the correct dosing and monitoring of the eyes. Other drugs in the treatment for RA or Lupus may have more frequent or serious side effects than Hydroxychloroquine so it would be wise to consider it a viable treatment option and not easily dismiss it because of the risk of what amounts to a fairly infrequent eye issue.

Article contributed by Dr. Brian Wnorowski, M.D.