Common vision problems
In the normal eye, light rays pass through the cornea at the front of the eye and the lens behind it focuses them as a sharp image onto the retina at the back. When the cornea or eye is misshapen, however, we see a distorted or blurred image (called a refractive error). The most common errors are:
- Myopia (short-sightedness) - light rays are focused in front of the retina, leading to an inability to see far, or blurred distant vision.
- Hyperopia (long-sightedness) - light rays aren’t yet in focus when they reach the retina, leading to blurred close-up vision.
- Astigmatism - light is focused at different points because the cornea is uneven, leading to blurred or distorted vision at all distances.
Laser eye surgery
Laser eye surgery is an irreversible procedure that’ll permanently alter the curvature of your cornea. (There are other procedures, such as a lens implant, but this is the most common.) Varying degrees of myopia, hyperopia and astigmatism can be corrected with laser eye surgery, either singly or in combination.
- An ophthalmologist (opthalmic surgeon) performs the operation, most commonly in a laser eye clinic, with a computer-controlled excimer laser that uses pulses of ultraviolet light to reshape the corneal surface — flattening it in short-sighted people, sculpting a steeper curve if you’re far-sighted and evening the curve out to correct astigmatism.
- Ophthalmologists are registered medical doctors who assess eyes, diagnose diseases, prescribe corrective devices and carry out medical and surgical procedures. However, they need no formal training to do laser eye surgery.
- For a description of the various laser eye surgery see Techniques and technologies.
Presbyopia — the age-related loss of our ability to focus on near objects — can’t be corrected with traditional laser surgery, but monovision or conductive keratoplasty may help. With monovision your eyes work independently — you use your dominant eye for distance and the other for near vision. This condition can occur naturally, or can be created with contact lenses or laser treatment. But not all people can tolerate it, so you may want to trial monovision first with contact lenses before you decide on surgery. Conductive keratoplasty (CK) is a radiofrequency heat treatment to the peripheral cornea that’s less invasive than laser surgery. It can be used to correct small degrees of long-sightedness or improve reading vision in one eye.