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, how long it may continue, or how significant it may become.
The effect of the hyperopic shift depends on the person's age and whether
the person is nearsighted or farsighted after the surgery:
Double vision, or diplopia, is a symptom to take seriously. Some causes of diplopia are relatively minor, but others need urgent medical attention. WebMD takes a look at the causes, symptoms, and treatments of double vision.