1. LASIK Aravind Eye Hospital, Tirunelveli

2. - Technological explosion in field of refractive surgery refractive surgery - 25 years later, 20 different refractive surgical techniques surgical techniques - Lasik currently most widely used Introduction

3. Indications a) Myopia (-1-to-15D) b) Hypermetropia (+1-to+8D) need for modification of current algorithms & better ablation profile to improve predictability need for modification of current algorithms & better ablation profile to improve predictability c) Astigmatism: - range from – 0.5 D. - range from – 0.5 D. - in mixed astig may not be possible to correct in a single ablation

4. Pre Operative assessment Patient selection - Vital importance - patient education - practical knowledge of procedure - preshyopic age group

5. Patient selection Criteria 1) Above 18 years of age 2) Stable refraction for atleast for one year 3) Refusal to use glass or Contact Lens 4) Contact lens intolerance 5) Absence of corneal pathology 6) Realistic expectation from the procedure 7) Properly obtained informed consent

6. History Stability of Refraction - stable atleast for preceding year - 18 years or Older - change in spherical equivalent should not be more than 0.50D over 12 months

7. Contact Lens - Reversible changes in refractive status of eye - Discontinue CL atleast 2 weeks in soft lens & 4 weeks in RGP / hard lens users.

8. Clinical Examination Uncorrected and best corrected visual acuity Uncorrected and best corrected visual acuity Manifest and cycloplegic refraction Manifest and cycloplegic refraction Fundus examination Fundus examination Slit lamp examination Slit lamp examination Keratometry and axial length Keratometry and axial length Corneal topography Corneal topography Pachymetry Pachymetry Pupil size Pupil size IOP IOP Specular microscopy Specular microscopy Glare & contrast sensitivity Glare & contrast sensitivity

9. Instruments (1) Laser machine (2) Eye tracking system (3) Foot switches (4) Micro keratome (5) Power supply (6) New blade (7) Suction ring

10. Patient Preparation  Some surgeons prefer to sedate  Eye cleaned with 5 % povidone iodine solution  Broad spectrum antibiotic  Patient, head must be parallel to floor and the chin & forehead should be at the same level  Patient cornea is perpendicular to laser beam  Topical anaesthesia drops applied 10 minutes prior to surgery and just before inserting speculum  Eye Drape.

11. Post operative management SIL after an hourSIL after an hour Steroids for 1 weekSteroids for 1 week Tear supplementsTear supplements

12. Conclusion Complications following Lasik though rare can be sight threatening - Demand for safety - Knowledge experience careful use and maintanence of microkerotome can reduce incidence of these complications