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
INTENDEDLEARNINGOUTCOMES“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
1ST 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 ofrefraction )
 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)
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. Rule out any of these :
 Corneal dystrophy.
 Vascularization.
 Active HSV .
 Corneal ectasia .”Keratoconus”
Refractive surgeries
Preoperative assessment (Identifies aCo-Pathology)
Cornea

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

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

18. Dilated Fundus Exam
Essential
Refractive surgeries
Preoperative assessment (Identifies aCo-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