His technique, called keratomileusis, meaning corneal reshaping (from Greek κέρας (kéras: horn) and σμίλευσις (smileusis: carving)), enabled the correction, not only of myopia, but also of hyperopia. It involves removing a corneal layer, freezing it so that it could be manually sculpted into the required shape, and finally reimplanting the reshaped layer into the eye. Although this early form of refractive surgery (keratomileusis with freezing) was improved in 1986 by Dr. Swinger (keratomileusis without freezing)[citation needed], it remained a relatively imprecise technique.