Coffee is known to stimulate the brain and keep you alert and awake – something most mornings need. That’s why it’s one of most Americans’ most popular ways to start the day. But, despite the many health benefits of coffee, there are also some risks. Excessive coffee consumption can negatively affect your eye health in the short and long term.

The objective of this study was to evaluate acute changes in retinal blood vessels after coffee consumption.

Even though most Americans consume caffeine in the form of coffee, you shouldn’t forget that many other beverages and some chocolate also contain caffeine. Therefore, it is possible to get too much caffeine if combined with coffee. 

Most ophthalmologists in New York agree that caffeine is safe in moderation. However, a high intake of coffee or caffeinated beverages can cause sudden spikes in blood sugar levels, which may result in blurry vision or sudden eyelid spasms. The eyes can also tingle and burn when you drink too much caffeine, a sensation that’s undoubtedly uncomfortable, especially during the workday.

It has been shown that people who drink more than three cups of coffee a day are at a higher risk of developing glaucoma. According to research, glaucoma results from increased pressure on the optic nerve, reducing vision. According to a couple of theories, glaucoma is caused by the accumulation of deposits on the eyes. Secondly, caffeinated drinks increase blood pressure and pressure in the eyes. 


The experts used a single patient monitoring system to measure the heart rate, blood pressure, and arterial oxygen saturation pressure of 22 healthy young adults. The subjects rested in a silent room for 15 minutes, and The researchers measured their blood pressure, heart rate, and arterial oxygen saturation pressure afterward.

The subjects’ eyes were imaged with optical coherence tomography (OCT) and OCT angiography (OCT-A), which were repeated 45 minutes after drinking 450 ml of coffee containing 130 mg of caffeine. This study assessed changes in the macular and optic nerve head neurovasculature.

Results Of The Study

Twenty-two study participants were aged 34 ± 6.8 years. Nine individuals (40.9%) were female, and there was no statistically significant difference in systolic and diastolic blood pressure or heart rate. Females had a 1.5% higher SpO2 than males by 1.5% (98.9% vs 97.4%, respectively, P = 0.008). There was no difference in pre- and post-coffee consumption.

According to the results, there was no significant change in the thickness of the peripapillary retinal nerve fiber layer or neural structural and vascular parameters of the optic nerve head. In addition, vessel densities (VDs) at the parafovea and deep capillary plexus at the perifovea were not significantly affected, despite significant decrements in superficial and deep vessel density.

Hence, drinking one cup of coffee (150 mg caffeine) statistically alters the thickness of the central fovea and the flow of blood around it but probably does not affect clinical outcomes in young adults with healthy eyes.

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