Laser Excimer Refractive Surgery

Excimer laser - disrupts molecular bonding and vaporizes tissue.

Two main techniques - both used in the correction of short sightedness (myopia) and less frequently for long sightedness (hypermetropia) or astigmatism.

Astigmatism simply describes a cornea that is more curved in one axis than the other - it has a surface contour shaped like a rugby ball as opposed to a football - which is spherical. It is not a disease, and is usually correctable with glasses or contact lenses. Progressive astigmatism may be associated with keratoconus (see p. 92). Reading glasses will be required for middle-aged patients postoperatively.

1. LASIK (Laser-assisted in situ keratomileusis).

2. PRK (Photo refractive keratectomy).

■ the most common refractive surgical procedure

LASIK (laser-assisted in situ keratomileusis)

Excimer laser applied to corneal stroma

Excimer laser applied to corneal stroma

Fig. 10.2b LASIK.

Corneal flap replaced and smoothed down

Lasered and reshaped underlying cornea

Lasered and reshaped underlying cornea

Fig. 10.2b LASIK.

occur.

■ best technique for high refractive errors

■ rapid visual recovery

■ little or no postoperative discomfort.

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