Stanford researchers analyzed millions of medical records and found that people with bladder cancer and color blindness have a 52% higher 20-year mortality rate than those with normal vision[1]. Color blindness makes it difficult to distinguish the color red, which complicates the detection of blood in the urine[1]. Blood in the urine is the most common early symptom of bladder cancer, which is usually painless in its early stages[1]. In patients with color blindness, the disease is diagnosed at a more advanced stage[1]. If the cancer is caught before it spreads outside the bladder, the five-year survival rate exceeds 70%[1]. When spreading to organs such as lungs, liver or bones, it drops to 9%[1]. The most common form of color blindness affects the perception of red and green colors[1][5].