Diagram of a normal eye
Myopia is characterised by blurred distant vision. Owing to an elongated shape of the eye in a myopic person the image does not form on but in front of the retina. This gives poor long distance vision. Myopia can sometimes occur alongside astigmatism (horizontal or vertical deformation of images).
If you are over 20 and your myopia is stable, you are probably a good candidate for refractive surgery, a laser operation on the cornea. If you also have astigmatism, the laser will correct both vision defects at the same time.
Hyperopia is characterised by blurred close vision. Owing to a shorter shape of the eye in a hyperopic person the image does not form on but behind the retina. This gives poor close vision. Hyperopia can sometimes occur alongside astigmatism to deform vision.
If your sight is stable, you can consider excimer laser treatment so as to remodel your cornea and recover clear sight, with the laser simultaneously correcting the hyperopia and the astigmatism.
Astigmatism is characterised by a horizontal or vertical deformation of images. The cornea is no longer spherical but oval shaped in someone with astigmatism. They find reading difficult with confusion of some characters.
Frequently associated with myopia or hyperopia, astigmatism can be corrected alone or in combination.
Presbyopia only appears after 40 years with a drop in the accommodation of the lens. You experience increasing difficulty in near vision and with the sensation of extending arms. If you are also hyperopic, presbyopia laser correction gives very good results. If you had very good sight before becoming presbyopic, it is not advisable to have the operation. If you wore glasses before becoming presbyopic, see your ophthalmologist for an assessment and confirmation that you are a good candidate.