Make your own free website on Tripod.com

Topic of the day

Home     Sure Success books  Questions Links

This page is aimed at  PG aspirants and we hope to update it daily with important topics for PG Entrance. If any errors have inadvertently crept into the matter here, please post it on the Message Board  so that we may rectify it. At the end of this page, please rate the usefulness of this article to you. 

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.

Please spare a moment and rate this article. Thank You

Sure Success in PG Medical Entrance
How do u rate this article?

Excellent/Useful
Good/Useful
Average
Bad/Not Useful


View Results
Home     Sure Success books  Questions Links