This document discusses various refractive surgery procedures aimed at correcting refractive errors such as myopia, hyperopia, and astigmatism by altering the cornea and/or crystalline lens. It describes procedures such as radial keratotomy, photorefractive keratectomy (PRK), laser-in-situ keratomileusis (LASIK), and phakic intraocular lens implantation. It provides details on how each procedure is performed and discusses complications that can occur. The document compares PRK and LASIK, noting that while LASIK recovery is quicker, it carries greater surgical risk due to creation of a corneal flap. Both procedures have around a 0.2-0.3% risk of losing more than

2. REFRACTIVE SURGERY
Capt dr shoaib Muhammad

3. 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

5. 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

6. • LENS SURGERY
–
–
CLEAR LENS EXTRACTION
PHAKIC POSTERIOR CHAMBER
INTRAOCULAR LENS IMPLANTATION
– PHAKIC ANTERIOR CHAMBER
INTRAOCULAR LENS IMPLANTATION

7. APPEARANCE FOLLOWING
RADIAL KERATOTOMY

8. APPEARANCE FOLLOWING LASER
THERMAL KERATOPLASTY

9. 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

10. 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

11. 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

12. PRINCIPLES OF
PHOTOREFRACTIVE
KERATECTOMY
FOR MYOPIA

13. 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

14. APPEARANCE DURING
PRK

15. 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

16. SUBEPITHELIAL CORNEAL
HAZE FOLLOWING PRK

17. 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

18. 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

19. CORNEAL FLAP CREATED
WITH A KERATOME DURING
LASIK

20. 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

21. WRINKLED FLAP FOLLOWING
LASIK

22. 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)

23. YOU
THANK