a seminar about intraocular lenses,their types , uses and complications

1. INTRA-OCULAR LENS
VISHNU NARAYANAN

2. What is intraocular lens?
• An artificial lens implanted in the eyes
• Replaces the crystalline lens
• To correct the optical power of the eyes
following:-
Lens being
clouded by
cataract
Refractive surgery

3. Primary vs secondary implantation
• Primary implantation – use of IOLs during
surgery for cataract
• Secondary implantation – implantation of IOL
to correct aphakia in a previosly operated eye

4. Parts of an IOL
• OPTIC
Part of the lens that focuses
light on the retina.
• HAPTIC
Small filaments connected to
the optic that hold the lens in
place in the eye
HAPTEN
OPTIC

5. HISTORY OF IOL
• K

6. THE FIRST IOL!!
• PMMA made lens – 45 year
old female after performing
extracapsular cataract
extraction
• Disc shaped bi-convex design
• Site- posterior chamber
• First generation IOL

7. EVOLUTION OF IOLs
1. First generation IOLs
• Ridley lenses
• Disadvantages – posterior dislocation
poor surgical technique
2. Second generation IOLs
• Rigid and semi-rigid anterior chamber IOLs
• Advantages – reduce posterior dislocation
• Disadvantage – corneal decompensation
UGH syndrome

8. 3. Third generation IOLs
• Iris supported lens
• Advantages- less corneal decompensation
• Disadvantages – iris chaffing
pupillary distortion
c/c inflammation
cystoid macular edema

9. 4. Fourth generation IOLs
• Modern anterior chamber lens
• Flexible loops and multiple point fixation
• Advantages – more stable, better design, less
complications
• Disadvantages – anterior chamber is not the
physiological site for IOL

10. 5. Fifth generation IOLs
• PMMA lenses
• Foldable and small incision lenses

11. MATERIALS USED FOR INTRAOCULAR
LENSES
Optic materials
1.Non-foldable-rigid IOL
• Polymethyl
methacrylate(PMMA)
2.Foldable IOL
• Silicone
• Hydrophobic acrylic
• Hydrophilic acrylic
3.Rollable/Ultra-thin IOL
• hydrogel
Haptic materials
• Polypropylene
• PMMA
• Acrylic

12. POSITIONING OF IOL
1. Posterior chamber
implantation
• Ciliary sulcus fixation
• In the bag fixation
• Scleral fixation
Eg:- modified C loop type
IOL

13. Ciliary sulcus fixation

14. In-the-bag fixation

15. Scleral IOL

16. 2. Anterior chamber
implantation
• angle supported IOLs
• Kelman multiflex type
IOL

17. 3. Iris- fixated lens
• Fixed on the iris with
claws,loops or sutures
• Eg- Singh and Worst’s
iris claw lens

18. Different types of haptic angulation
relative to the plane of optic:-
For posterior chamber lens:-
• 100 anterior angulation to keep the optic
part away from the pupil.
For anterior chamber lens:-
• Posteriorly angulated lens to vault the
intraocular lens away from the pupil

20. FOCUSSING ABILITY OF IOLs
1. Unifocal intraocular lens
• Lens with unifocal power
• Can have problem with near vision

21. 2.Multifocal IOLs
• Simultaneous vision
lenses
• Based on either refractive
or diffractive optics
• Psuedoaccomodation lens

22. 3.Accomodative IOLs
• Exhibit anterior movement of optic
to improve near vision

23. Special function IOLs
TORIC IOLs
• Correct any associated
astigmatism
ASPHERIC IOLs
• Reduce spherical
aberration

24. ANIRIDIA IOLs
• Cover the defects of aniridia or
partial iris loss as in trauma
• Has a black diaphragm over the
optic
PIGGYBACK IOLs
• An IOL piggybacking onto an
existing IOL or simultaneous
implantation of 2 IOLs

25. BLUE LIGHT FILTERING IOLs
• Lenses are yellow colored to screen out UV
Light and blue spectrum
• Reduced risk of age related macular
degeneration
PHOTOCHROMATIC IOLs
• UV absorbing photo chromes

26. IMPLANTABLE MINIATURE
TELESCOPE
• Miniature implantable Galilean
telescope
• Implanted in posterior chamber
• Contains number of micro lenses
in the optic which gives a
magnification of about 3 at the
central visual field
• Used to treat macular
degeneration

27. TELESCOPIC IOLs
• New generation miniature
telescopes which uses 2 mirrors
instead of lens to provide
magnification with minimum
loss of peripheral vision

28. Phakic IOLs
• IOLs used to correct myopia with the eye’s
natural lens being untouched
• Implantable contact lenses
1. Angle supported lens
2. Iris – fixated lens
3. Sulcus supported lens

29. BIOMETRY
THEORETICAL FORMULAE
• Binkhorst formula
• Colenbrander’s formula
• Gull strand’s formula
• Hoffer’s formula
EMPERICAL FORMULAE
• Modified Sanders-Retzlaff-Kraff formula
• SRK II
• SRK III
• SRK T
• Haigis formula

30. Binkhorst formula
• E= [N/(L-C)] – NK/(N-KC)]
E
• Emmetropic IOL power
L
• Axial length of the eye
K
• Corneal dioptric power
C
N
• Psuedophakic length of anterior chamber
• Refractive index of aqueous and vitreous humor

31. Modified Sanders-Retzlaff-
Kraff formula
• Based on the statistical correlation
between calculated and observed
refractive error after ocular
implantation.

32. Modified SRK Formula
• E=A - 2.5L - 0.9K
• Parameters used in the formula are
estimated by
• A-scan ultrasonographic sonometry and
keratometry
• Instrument - biometer

33. E=A - 2.5L - 0.9K

34. • Power ( I )required to produce Required post
operative refraction ( R ) ,
I = E – cr R
• cr – empirical constant
cr = 1 if E < 14
cr = 1.25 if E > 14

35. Complications of IOL implantation
• Mechanical damage to the IOL
• Dislocation
• Bullous keratopathy
• Posterior capsule rupture
• Anterior capsule opacification
• Posterior capsule opacification
• Calcium deposits within the optic of hydrophilic
intraocular lens
• Adherence
• UGH syndrome
• Sunset syndrome

36. Sunset syndrome

37. “Lens of the future”-liquid injectable
IOLs
• A new IOL concept that combines an acrylic
IOL with a liquid, injectable IOL may someday
allow patients to retain accommodation.
• Following IOL implantation, liquid IOL is injected
and capsular bag is inflated fully and IOL kept in
place
• Mechanism- forward movement and thickening
of lens