Yes, it is true that some people's eyes may appear red after drink coffee. The main ingredients of coffee is caffeine, and caffeine can get into your blood vessel of eyes and make your eyes look red and affect your eye vessels. Over intaking of caffeine will accelerate your blood circulation and make your eye muscles spasm. That's how caffeine affects your eyes and makes your eyes look red.
You eyes will appear red if you drink too much coffee. Because the caffeine may keep you alert all the time, then you'll possibly get exhausted. Bloodshot eyes show up as the symptom, it denote strain and fatigue.
Do not drink too much coffee, especially when you're under pressure. Once you get red eyes, stop drinking coffee, and relax more. Use some artificial tears to relieve your eyes.
Yes, excessive and some unreasonable consumption of coffee can cause red eyes and it can be very uncomfortable. Since there are a lot of caffeine in coffee can you can get caffeine allergy which can cause red eye irritation and red eyes. What's more, if you drink caffeine before bed, I tend to not fall sleep and then you can have poor sleeping, which can lead to your red eyes in return, so just do not drink coffee a lot and never drink it before bed.