Laser Eye Surgery Articles                

Astigmatism is a quite widespread condition that concerns the structure of one's eye. The condition is where the cornea, which is the outer lens of the eye, is of an irregular shape. This front part of the eye should be rounded (looking like an oval bubble on the surface of the eyeball), but with astigmatism, the cornea is more like the shape of an egg or a football. The effect of this is that the light that goes into the eye does not cleanly hit the receptors at the back of the eye. Instead, it can be refracted, meaning it is detected over more than one point, resulting in a blurred image interpreted by the brain.

Patients with astigmatism can have difficulty with objects at either short range or distant range, or both. Some people who do not wear glasses can have astigmatism without realising it, with common symptoms including eye strain, the need to squint to clarify words and letters (squinting compresses the shape of the eye back to 'normal') and resulting headaches. A large proportion of people who discover they need corrective glasses learn that they have astigmatism. Laser eye surgery can be used as a way of permanently treating astigmatism. The irregular 'football' shape of the cornea means that one slope of the cornea's shape is steeper than the other.

Therefore, laser eye surgery effectively works by 'evening out' the cornea, by removing cells on the steeper slope, to give a more even rounded shape, which is done using a specialist technique known as Photo-Astigmatic Refractive Keratectomy (PARK).

Myopia is the medical term for what is more generally known as short sightedness or near sightedness. One cause of myopia can be astigmatism, as described above, however, it can also be caused by more general 'problems' in the structure of the eye. Myopia tends to occur where the eye is too long for the light entering the eye to properly reach the receptors at the back of the eye (at the retina). Myopia is the most common condition affecting general eyesight and is the primary cause for most glasses wearers to need such equipment. If you have myopia, you will notice a minus (-) on your prescription, along with a number, within 0 to about 10. The unit of measurement is called dioptres (abbreviated simply as 'd' on a prescription), with a number closer to -10 indicating more severe myopia.

Myopia can be treated with laser eye surgery, although the best results will be experienced by those patients with a prescription of between 0 and -6 dioptres. Those with a more severe prescription are more prone to side effects such as loss of night time vision and a 'halo' effect around bright lights, caused by the pupils expanding into the treated part of the eye.

Myopia is a hereditary condition and often gradually becomes worse through life, although the condition often stabilises in young adulthood (early 20s). For this reason, most laser eye surgery clinics will have a minimum age requirement, which may be more than 21.