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LASIK—PG ENTRANCE NOTES

Laser Assisted in-situ keratomileusis (LASIK)

INDICATIONS

1. Approved range for myopic correction is – 0.5 to –14.00 diopters (-2 to –12 D; Parsons’), with up to 5 diopters of astigmatism
2. Residual stromal bed thickness should be at least 250 mm (i.e. total corneal thickness of 550-600mm)
3. Hyperopic corrections have been approved for +4.00

 CONTRAINDICATIONS

1. Unstable refractive error.
2. Age less than 21 years.
3. Active collagen vascular disease (especially in the presence of iritis or scleritis).
4. Pregnancy.
5. Presence of a pacemaker.
6. Any ongoing active inflammation of the external eye (eg, conjunctivitis, severe dry eye).
7. Refractive error outside the range of laser correction.
8. Keratoconus

 PATIENT SELECTION FOR LASIK (preoperative workup)

Contact lens wear should be discontinued prior to the examination

3 days for soft contact lens wear

2 weeks for rigid gas permeable lenses.

 A complete eye examination

Manifest and cycloplegic refraction

Slit lamp examination

Dilated fundus examination –Indirect Ophthalmoscopy

Corneal topography

An estimate of scotopic pupil size is helpful in screening candidates that may be at risk for postoperative glare

 PROCEDURE

1. Paint, drape, place speculum.
2. A suction ring placed on the eyeball elevates IOP to about 60 mmHg (temporary blackout of vision occurs).
3. The microkeratome advances and creates an epithelial flap, which is hinged usually nasally.
4. The flap is lifted and laser ablation of stroma done.
5. EXCIMER LASER is used.
6. Leave behind residual corneal thickness of at least 250 microns.
7. Irrigate bed with saline and close the flap. No sutures. It sticks by itself.
8. Use antibiotics and steroid drops for about 1 week.

 ENHANCEMENTS

·         Enhancement LASIK (i.e. repeat procedure) can be performed but usually after 3 months of table refraction.

SUPER VISION

·         Wavefront technology in LASIK aims to corrct all aberrations of the eye to give vision beyond 6/6 – super vision.

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