A multi-center study of radial keratotomy (RK) outcomes funded by the National Eye Institute. Ten-year results of RK patients who had the surgery in 1983 were published in Archives of Ophthalmology in October 1994.

The study found that seven out of ten patients who had the operation on both eyes no longer wore or required corrective lenses ten years after surgery, and 85% of patients saw 20/40 or better without glasses. It concluded that RK is a "reasonably safe operation" that can "effectively reduce but not eliminate myopia" (nearsighted, shortsighted vision).

The study also found that 43% of patients experienced a hyperopic shift following surgery over the ten-year period. These patients typically experienced an improvement in their vision as their refractive error moved closer to 20/20. It is for this reason that ophthalmic doctors will often intentionally undercorrect their patients, then monitor the rate of healing before performing a follow-up enhancement procedure.

Patients whose vision had achieved full correction or near full correction through surgery and who experience a hyperopic shift could become farsighted and need to wear glasses.