Since it first became available, LASIK has undergone many refinements, such as the availability of bladeless surgery. An ophthalmologist located near Londonderry or Manchester can use an IntraLase laser to create the corneal flap, for instance. After creating and lifting the corneal flap, the eye doctor can reshape the cornea and replace the flap. The reshaping of the cornea allows for the correction of refractive errors because light can bend properly as it enters the eye. The three refractive errors that LASIK eye surgery can correct are farsightedness, nearsightedness, and astigmatism.
Farsightedness 
Eye doctors diagnose patients with farsightedness, or hyperopia, when they can clearly see objects at a distance, but not those that are close to the patients. Hyperopia may occur if the cornea lacks sufficient curvature or if the eyeball is too short. When the light rays enter the eye of a farsighted person, they are focused behind the retina. Patients with farsightedness may suffer from eye strain, achy eyes, and headaches, particularly after close work such as reading or using a computer. They may find themselves holding books and other items further away from the head to compensate.
Nearsightedness
Patients with nearsightedness have the opposite problem as those with farsightedness. Nearsightedness, or myopia, allows patients to see close objects clearly, but distant objects appear blurry. Myopia is diagnosed in people who have corneas with too much curvature or eyeballs that are too long. Because of the excessive curvature, the light entering the eye is focused on an area directly in front of the retina, instead of on it. Like farsightedness, nearsightedness can cause eye strain, headaches, and fatigue. People may find themselves squinting to see more clearly. They may have trouble seeing road signs or playing sports, but reading is generally easier.
Astigmatism
Lastly, LASIK eye surgery can correct astigmatism. It’s not uncommon for a patient to have astigmatism along with farsightedness or nearsightedness. Astigmatism occurs due to the irregular shape of the cornea, which prevents the light rays from focusing properly on the retina. The resultant blurry vision can lead to eye strain and discomfort.