Refractive surgery copy

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Refractive surgery copy

  1. 1. REFRACTIVE SURGERY Capt dr shoaib Muhammad
  2. 2. INTRODUCTION • A RANGE OF PROCEDURES AIMED AT CHANGING REFRACTION OF THE EYE BY ALTERING THE CORNEA AND / OR CRYSTALLINE LENS • REFRACTIVE ERRORS CORRECTED INCLUDE MYOPIA, HYPERMETROPIA AND ASTIGMATISM
  3. 3. CORRECTION OF MYOPIA • CORNEAL SURGERY – RADIAL KERATOTOMY • RADIAL INCISIONS IN PERIPHERAL CORNEA – PHOTOREFRACTIVE KERATECTOMY – LASER-IN-SITU KERATOMILEUSIS (LASIK) – INTRASTROMAL PLASTIC RINGS • CAUSE CENTRAL CORNEAL FLATTENING
  4. 4. • LENS SURGERY – – CLEAR LENS EXTRACTION PHAKIC POSTERIOR CHAMBER INTRAOCULAR LENS IMPLANTATION – PHAKIC ANTERIOR CHAMBER INTRAOCULAR LENS IMPLANTATION
  5. 5. APPEARANCE FOLLOWING RADIAL KERATOTOMY
  6. 6. APPEARANCE FOLLOWING LASER THERMAL KERATOPLASTY
  7. 7. CORRECTION OF HYPERMETROPIA • CORNEAL SURGERY – PRK • CAN CORRECT LOW DEGREES OF HYPERMETROPIA – LASIK • CAN CORRECT UPTO 4 D – LASER THERMAL KERATOPLASTY • HOLMIUM LASER • LENS SURGERY – PHAKIC INTRAOCULAR LENS IMPLANTATION AT AN EARLY STAGE
  8. 8. CORRECTION OF ASTIGMATISM • CORNEAL SURGERY – ARCUATE KERATOTOMY • MAY BE COMBINED WITH COMPRESSION SUTURE PLACED IN PERPENDICULAR MERIDIAN – PRK • CAN CORRECT UPTO 3 D – LASIK • CAN CORRECT UPTO 5 D • LENS SURGERY – USING A TORIC INTRAOCULAR LENS IMPLANT – POSTOPERATIVE ROTATION OF IMPLANT
  9. 9. PHOTOREFRACTIVE KERATECTOMY • PERFORMED WITH EXCIMER LASER • MYOPIA TREATED WITH ABLATING THE CENTRAL ANTERIOR CORNEAL SURFACE • 10 MICROMETER ABLATION CORRECTS 1 D OF MYOPIA • CAN CORRECT – MYOPIA UPTO 6 D
  10. 10. PRINCIPLES OF PHOTOREFRACTIVE KERATECTOMY FOR MYOPIA
  11. 11. TECHNIQUE OF PRK • VISUAL AXIS MARKED • PATIENT FIXATES AT AIMING BEAM OF THE LASER • LASER APPLIED TO ABLATE ONLY BOWMAN LAYER AND ANTERIOR STROMA • TAKES USUALLY 30 – 60 SECONDS
  12. 12. APPEARANCE DURING PRK
  13. 13. COMPLICATIONS OF PRK • • • • SLOW HEALING EPITHILIAL DEFECTS CORNEAL HAZE POOR NIGHT VISION REGRESSION OF REFRACTIVE CORRECTION • UNCOMMON PROBLEMS INCLUDE – – – – – – – DECENTRED ABLATION SCARRING IRREGULAR ASTIGMATISM HYPOASTHESIA STERILE INFILTRATES INFECTION ACUTE CORNEAL NECROSIS
  14. 14. SUBEPITHELIAL CORNEAL HAZE FOLLOWING PRK
  15. 15. Excimer Laser Epithelial Keratomileusis(LASEK) Corneal epithelium is loosened and set aside, or removed, refractive procedure is performed with the excimer laser (PRK), Finally epithelial layer is brought back to recover the cornea again and held in place Indications  Myopia up to – 6.0 diopters  Hypermetropia up to + 3.0 diopters  Astigmatism up to 3.0 diopters Advantage  Less glare problem than PRK
  16. 16. LASER IN-SITU KERATOMILEUSIS • CURRENTLY MOST FREQUENTLY PERFORMED REFRACTIVE PROCEDURE • CAN CORRECT – – – HYPERMETROPIA OF UPTO 4 D ASTIGMATISM UPTO 5 D MYOPIA OF UPTO 12 D • TO PREVENT CORNEAL ECTASIA, A RESIDUAL CORNEAL BASE OF 250 MICROMETER THICKNESS MUST REMAIN AFTER THE FLAP HAS BEEN CUT AND TISSUE ABLATED
  17. 17. CORNEAL FLAP CREATED WITH A KERATOME DURING LASIK
  18. 18. COMPLICATIONS OF LASIK • OPERATIVE FLAP-RELATED – – – – – BUTTONHOLES THIN FLAPS FLAP AMPUTATION INCOMPLETE OR IRREGULAR FLAP RARELY CORNEAL PERFORATION • POSTOPERATIVE – WRINKLING, DISTORTION OR DISLOCATION OF FLAP – EPITHELIAL INGROWTH UNDER THE FLAP – DIFFUSE LAMELLAR KERATITIS – PERIPHERAL CORNEAL INFILTRATES
  19. 19. WRINKLED FLAP FOLLOWING LASIK
  20. 20. PRK vs. LASIK Same destination; Different journey PRK LASIK Day one: “Oowww!” Less surgical risk Slower recovery 80% 20/20 Haze No flap 0.2 – 0.3% risk visual loss (>2 lines) Day one: “Wow!” Greater surgical risk Quicker recovery 80% 20/20 No haze Flap 0.2 – 0.3% risk visual loss (>2 lines)
  21. 21. YOU THANK

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