September 2019

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Good news about caffeine and cataract


by Stefanie Petrou Binder, MD EyeWorld Contributing Writer

The more coffee you drink, the higher the concentration of antioxidants reaching the lens, according to researchers. New data indicates that drinking coffee before cataract surgery increases the caffeine levels in the lens capsule in a dose dependent manner. Based on the assertion that caffeine’s antioxidant nature could have a positive effect on the prevention of cataract blindness, this finding may be the news coffee lovers have been waiting for.
Speaking on the effects of caffeine on the eye during a free paper session at the 23rd European Society of Cataract and Refractive Surgeons Winter Meeting, Manuel Ruiss, MSc, presented study results that assessed caffeine concentrations in the eyes of patients who drank coffee just before cataract surgery.1 He worked on the study with his supervisor, Martin Kronschläger, MD.
“Cataract is still the leading cause of blindness across the globe, with no approved drug to prevent the disease,” Mr. Ruiss said in his presentation. “The crystalline lens is constantly subjected to oxidative stress, for instance via ultraviolet radiation. In cataract, reactive oxygen species are increased, like hydrogen peroxide, whereas antioxidants like glutathione, a primary lenticular antioxidant, are decreased. Experimental animal studies and observational data suggest antioxidants might retard the development of cataract.”

Studying the effects of coffee

The study included 40 patients (80 eyes) scheduled for bilateral cataract surgery, with a gap of 1 week between surgeries. The patients were examined 1 week prior to surgery and asked to abstain from caffeine until the second eye surgery, encompassing 2 weeks of no caffeine. There were no statistically significant differences among age, weight, and usual coffee consumption in the study patients. Patients drank an average of 1.6–2.3 cups of coffee/day. The mean patient age was between 72 and 78 years, and their weight was between 77 and 80 kilos.
Shortly before the second cataract surgery, the patients were asked to consume coffee and were randomized into different groups: 0 mg caffeine (n=10), 60 mg caffeine (n=10), 120 mg caffeine (n=10), and 180 mg caffeine (n=10). The time between coffee consumption and surgery was 144–191 minutes (2–3 hours).
After cataract surgery with capsulorhexis, the lens capsule and lens epithelial cells were collected and sent to a lab for a gas chromatography-mass spectrometry analysis of caffeine concentration. Of the 80 eyes of 40 patients that were included, seven patients (14 eyes) were excluded due to protocol noncompliance. The results showed that coffee intake before cataract surgery increased the caffeine levels in the lens capsule in a dose dependent fashion.

Past caffeine studies

Past studies have examined the antioxidant effect of caffeine and its ability to inhibit oxidative damage. In one such study, caffeine was thought to be an important antioxidant, being a scavenger of free radicals. The study likened the general antioxidant ability of caffeine to that of the established biological antioxidant glutathione and significantly higher than ascorbic acid.2 Another study from the literature demonstrated the protection factor (PF) of caffeine against UV radiation to be higher than the PF of both vitamin C and vitamin E.3
“Up until now there has been some evidence that caffeine or antioxidants might play a protective role for lens epithelial cells and a preventive role for cataract, however, no one has shown if caffeine can protect the lens and the lens capsule through peroral intake. Epidemiological findings show that caffeine has had a positive effect on the prevention of cataract blindness,” Mr. Ruiss said.
The incidence of cataract blindness in humans was significantly lower in groups consuming higher amounts of coffee in comparison to those groups with lower coffee intake, according to a study that credited both its antioxidant and bioenergetic effects on the lens. The study assessed per capita coffee consumption in kg/year as obtained from the Food and Agriculture Organization of the United Nations and from other sources.4 The dietary total antioxidant capacity, including coffee, of middle-aged and elderly women was inversely associated with the risk of age-related cataract, according to yet another study on the subject. The Swedish population-based study found that coffee contributed 15% of total antioxidant capacity along with fruit and vegetables (44%) and whole grains (17%).5
“Caffeine accumulates in the lens capsule and epithelial cells after oral intake of coffee, making it a potent candidate to delay the onset of cataract,” Mr. Ruiss said.

About the doctor

Manuel Ruiss, MSc
Vienna Institute for Research
in Ocular Surgery
Hanusch Hospital
Vienna, Austria

References

1. Kronschläger M, et al. Pharmacokinetics of caffeine in the lens capsule/epithelium after peroral intake: a pilot randomized controlled study. Invest Ophthalmol Vis Sci. 2018;59:1855–1860.
2. Devasagayam TP, et al. Caffeine as an antioxidant: inhibition of lipid peroxidation induced by reactive oxygen species. Biochim Biophys Acta. 1996;1282:63–70.
3. Kronschläger M, et al. Caffeine eye drops protect against UV-B cataract. Exp Eye Res. 2013;113:26–31.
4. Varma SD. Effect of coffee (caffeine) against human cataract blindness. Clin Ophthalmol. 2016;10:213–20.
5. Rautiainen S, et al. Total antioxidant capacity of the diet and risk of age-related cataract: a population-based prospective cohort of women. JAMA Ophthalmol. 2014;132:247–52.

Relevant financial interests

Ruiss: None

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