Most people who have radial keratotomy (RK) surgery gradually become more farsighted for at least 8 to 10 years after surgery. This is called the hyperopic shift. It is not clear what causes the shift. It's also not clear how long it may last or how bad it will get.
The effects depend on the person's age and whether the person is nearsighted or farsighted after the surgery.
- People who are still slightly nearsighted after surgery (undercorrected) may find that their distance vision slowly improves as the hyperopic shift occurs.
- People younger than 40 may not notice the shift. That's because their eyes can adjust to the change.
- People around age 40 may get presbyopia sooner as a result of the hyperopic shift. They may need reading glasses.