Hello! The reason why the letters in your center vision disappear is because of a condition called central scotoma. This condition is caused by damage to the macula, which is the part of the eye responsible for sharp, central vision. It can be caused by age-related macular degeneration, diabetes, or other eye diseases. Symptoms include blurred vision, difficulty reading small print, and difficulty recognizing faces. Treatment options vary depending on the cause of the condition and may include medications, laser treatments, or surgery. If you are a college student and are experiencing these symptoms, it is important to see an eye doctor as soon as possible for diagnosis and treatment.