Near, far, reading. Www.2020vision. Com/refractive_error. Html has the answers in detail.
Refractive errors. Myopia means nearsightedness, with the ability to see near but not far away. Hyperopia, or farsightedness is usually not an issue for younger people but causes issues in older adults. Astigmatism occurs when the front surface of the eye is not round and causes distortion. It is corrected like the above errors. Presbyopia means "old eyes" and refers to the need to reading glasses in adults.
Each is different. Hyperopia is far sightedness, Myopia is near sightedness and presbyopia means trouble focusing for reading and close objects. Presbyopia at age 31 would be very unusual but because a farsighted eye has to focus itself, early presbyopia and bifocals may be needed. Myopes need glasses for distance. If you have all three and each eye is different, you indeed may need bifocals.