REFRACTIVE SURGERY.pptx

short notes for undergraduate medical students regarding refractive surgeries

1. Refractive Surgery Dr. Mohamed F Elbarghathi By Assistant lecturer , Ophthalmology department Faculty of medicine, University of Benghazi

2. Explain the steps - including history, ocular examination, and investigations - in evaluating whether a patient is an appropriate candidate for refractive surgery. 1 INTENDED LEARNING OUTCOMES “ ILOs ” Identify the various techniques used in refractive surgeries. 2 For (LASIK), describe surgical techniques and complications. 3 State possible contraindications to corneal based refractive surgery in patients with pre-existing ocular or systemic disease. 4

3. Refractive surgeries INTRO  Group of procedures that may be surgical or laser assisted, on cornea or lens.  The surgeries on cornea are done far more frequently than on the lens  Principle in corneal refractive surgeries is to change the corneal curvature to change its refractive power  Some of the eyes that may benefit visually by surgery cannot be operated due to existing contraindications .

4. Refractive surgeries HISTORY 1965 1970 1983 1991 1996 Jos - Ignacio Barraquer Introduction of Keratomileusis . Fyodorov invents Radial Keratotomy  Invention of the Excimer Laser PRK and LASIK approved by FDA Slade / Brint 1 ST LASIK surgery Evolution of Femtosecond Laser in Refractive Surgery 2001

5. Refractive surgeries CLASSIFICATION CORNEA BASED R.K 01 PRK 02 LASIK 03 SMILE 04 LENTICULAR BASED PHAKIC  APHAKIC  IOL CLEAR LENS EXTRACTION >45Y PHAKIC IOLs (Young) AC PC BIOPTICS Combination of the two

6. Refractive surgeries Preoperative assessment (History ) Corneal ectasia (KC) January December

7. Refractive surgeries Preoperative assessment (History ) Why age is important ? Ranges between 20 and 45 years  Under 20 years have higher chances of being unstable  over 45 years have following drawbacks: 01- Is the age of presbyopia. 02- Many of them will develop lenticular changes ( Cataract).

8. Refractive surgeries Preoperative assessment (stabilization of refraction )  The procedures should be done only on eyes that have unchanged errors of refraction, at least 1 year prior to surgery. January December

9. Refractive surgeries Preoperative assessment (Contraindications) Contraindications 1.. 2. Allergic keratoconjunctivitis . 3. Diabetes mellitus. 4. Pregnancy. Absolute C/I Infection 01 Keratoconus 02 Glaucoma 03 Posterior segment anomalies 04 Immune suppression 05 Amblyopia 07 Corneal dystrophies 06 Relative C/I Dry eyes 01 Allergic keratoconjunctivitis 02 Diabetes mellitus 03 Pregnancy 04

10. 1- No improvement. Organic pathology , Amblyopia Pin hole 2- Improvement. Refractive surgeries Preoperative assessment (Visual acuity & Refraction)

11. Subjective assessment of Refractive error and BCVA Objective measurement of Refractive error Visual acuity measurement UAVA Refractive surgeries Preoperative assessment (Visual acuity & Refraction)

12. BCVA 02 UAVA 01 Refractive surgeries Preoperative assessment (Visual acuity & Refraction)

13. Cycloplegia should be performed to all cases . to refine the sphere. By neutralizing accommodation . Refractive surgeries Preoperative assessment (Visual acuity & Refraction)

14.  LASIK (Sphere) +5.00 TO -14.00 D (Cylinder) Up to 5.00 D  PRK (Sphere) +6.00 TO -12.00 D (Cylinder) Up to 4.00 D  Phakic intraocular lens (Sphere) –3.00 to –20.00 D (Cylinder) Up to 4.00 D Toric lens  Refractive lens Exchange (Sphere) All ranges (Cylinder) Up to 4.00 D toric lens Refractive surgeries Preoperative assessment (Visual acuity & Refraction) Reference : 2022-2023

15. Cornea Rule out any of these :  Corneal dystrophy .  Vascularization.  Active HSV .  Corneal ectasia .”Keratoconus” Refractive surgeries Preoperative assessment (Identifies a Co-Pathology) Cornea

16. Cornea Rule out any of these :  Cataract .  Ant or Post Lenticonus  Lens Subluxation Refractive surgeries Preoperative assessment (Identifies a Co-Pathology) Lens

17.  Tear meniscus height .  Tear film break up time .  Schirmer test . EXCLUDE :-  Severe dry eye .  Autoimmune disease . Refractive surgeries Preoperative assessment (Identifies a Co-Pathology) Pre ocular tear film

18. Dilated Fundus Exam  Essential Refractive surgeries Preoperative assessment (Identifies a Co-Pathology)

19. Corneal Tomography. Refractive surgeries Preoperative assessment (Investigation) Keratometry measurements 01 Corneal thicknes measurements 02 Pentacam

20. CORNEAL REFRACTIVE PROCEDURE

21. Radial keratectomy Series of 4-8 deep, radial corneal stromal incision 01 Weaken the paracentral & peripheral cornea & flatten the central cornea 02 Complications Bullous keratopathy Low stability of refraction

22. Radial keratectomy

23. PHOTOREFRACTIVE KERATECTOMY ( PRK ) Outer layer of cornea is removed then excimer laser is applied. 01 No flap created 02 Vision improves as surface heals from 7 to 21 days. 03 Longer recovery period (> 2 weeks) 04 Discomfort present during healing 05

24. PHOTOREFRACTIVE KERATECTOMY ( PRK )

25. LASIK (Laser-assisted in situ keratomileusis) Most commonly performed refractive surgery 01 Excimer laser ablation of corneal stroma beneath a corneal flap that is created with a mechanical or femtosecond laser microkeratome 02

26. LASIK (Laser-assisted in situ keratomileusis) Steps of LASIK Flap creation Apply excimer laser Flap returned

27. LASIK Illustrative Animation Start animation

28. Femto LASIK Illustrative Animation Start animation

29. LASIK Vs PRK

30. Unwanted astigmatism 05 Corneal ectasia 04 Flap complication 03 Epithelial trauma 02 Under/over correction 01 Laser vision correction complications

31. Excimer & Femto laser machine

32. Femto SMILE

33. LENTICULAR REFRACTIVE PROCEDURE

34. Phakic Intra ocular lenses (IOL)  Artificial lenses implanted in the anterior or posterior chamber in the presence of the natural crystalline lens to correct refractive errors. Types AC iris-fixated ( Artisan ) Posterior chamber IOL ( ICL )

35. AC iris-fixated ( Artisan )

36. Posterior chamber IOL (ICL )

37. Complication of phakic IOLs  PC IOLs - Pupillary block . - Dislocation. - 2ry Glaucoma . - Iritis, Cataract.  AC IOLs - Pupillary block . - Dislocation. - 2ry Glaucoma . - Iritis.

38. Thanks Dr Mohamed Elbarghathi