Photorefractive keratectomy (PRK).PRK is sometimes used if you have a low to moderate degree of nearsightedness or farsightedness, or if you have nearsightedness with astigmatism.

• 屈光性角膜切除术（PRK）：当你有低于中等度数的近视或者远视，或者近视加散光，有时会选择PRK。