intraocular lens

1. CURRENT TIME’S IOL
VASIUR RAHMAN
R.P. Centre for ophthalmic science
All India Institute of Medical Science
New Delhi.

2. BIRTH OF IOL
First Person-
Sir Harold Ridley
Royal Air force pilots who
sustained eye injury during
world war second involving
PMMA as wind shield material
did not show any rejection or
foreign body reaction.

3. First IOL

4. Generations of IOLs
8 generations till now.
Rigid posterior chamber belongs to Vth generation.
Foldable IOL- VIth generation
Multifocal IOL- VIIth genration
Phakic refractive IOLs &
accomodative IOLs- VIIIth generation

5. Material for IOL
• Poly methyl Methacrylate (PMMA) -
Rigid, chemically stable compound.
• Silicon hydrogel & Acrylic-
– foldable material
– Phacoemulsification & MICS
PMMA material

6. Structure of IOL
ACIOL PCIOL

7. Traditional IOLs
• Traditional IOLs are
monofocal, meaning they offer
vision at one distance only (far,
intermediate or near).
• patient must wear eyeglasses
or contact lenses in order to
read, use a computer or view
objects at arm's length.

8. Premium IOLs:
• Aspheric IOLs
• Toric IOLs
• Multifocal IOLs
• Accomodating IOLs

9. Aspheric IOL
• slightly flatter in the periphery and are
designed to provide better contrast
sensitivity
• Reduce the abrassions
• Gives better visual aquiety

11. Chromatic Aberration
• Uneven focusing of an optical system which
causes wavelengths of light to have different focal
points thus decreasing optical performance

12. • Chromatic aberration from IOLs may negatively impact:
– Visual acuity
– Contrast sensitivity
– Functional vision
• The chromatic aberration of optical materials can be expressed by their
Abbe numbers
• The higher the Abbe number the lower the chromatic aberration and the
higher the retinal image quality

13. Abbe number
• The Abbe number, also known as
the V-number or constringence of
a transparent material, is a
measure of the
material's dispersion (variation of
refractive index with wavelength) in
relation to the refractive index, with
high values of V indicating low
dispersion (low chromatic
aberration). It is named after Ernst
Abbe (1840–1905), the German
physicist who defined it

14. Multifocal IOLs
A multifocal lens implant focuses light from distance and near
simultaneously. This feature addresses both distant and
near vision and makes the recipient less dependent on
glasses or contact lenses
• Currently available MF use either Diffractive or Refractive
optics

15. refractive multifocal IOL
• Two zone lens
• Central near vision segment
surrounded by distant vision
segment
• Disadvantage in bright sunlight
• Annulus type-
• Central portion contain distant
vision refraction
• Refractive provides excellent
intermediate and distance vision

16. diffractive multifocal IOL
• Near and distant correction is put in each of concentric ring
• Utilize the principle of wave optics
• Step height is in the range of wavelength of light
• 82% focus on 2 major foci
• 41% for near vision
• 41% for distant vision
• 18 % scattered & lost

17. Disadvantage of MF
• Light intensity
• Contrast sensitivity
• Off axis aberrations
• glare and haloes around lights at night, a
feature that is inherent to multifocal lenses
• most patients find that they get used to this
phenomenon with time and the glare and
haloes become less obvious

18. Toric IOLs
• designed to correct
astigmatism at corneal
plane.
• Correct astigmatism at
corneal plane only.
• Only one vision is corrected.

19. Vision with
cataract
Vision with
normal IOL
Vision with Toric
IOL

21. IOL for Refractive Error
• . This type of IOL is also
called Phakic intraocular
lens (PIOL) and the
crystalline lens is not
removed.
• alternative to LASIK
• (PIOLs) can be either
spheric or toric—the latter
is used for astigmatic eyes

22. Accommodating IOLs
• Accommodating IOLs interact with ciliary
muscles and zonules using hinges at both ends
to ―latch on‖ and move forward and backward
inside the eye.
• provide excellent vision at all distances (far,
intermediate, and near)
• same quality of distant vision as in monofocal
lens
• No loss of contrast sensitivity
• No halos at night
• So Advantage over MF

24. Fact
• Patients should expect to achieve "social" near vision with the
accommodative IOL.
• For example-watch faces, cell phones, price tags, grocery labels,
computer screen text and magazine size print under average
lighting conditions.
• Patients whose main goal is to sit and read small print in dim
lighting conditions for prolonged periods of time or do other very
precise near work are likely to be disappointed with the unaided
near vision available from the accommodative IOLs.
• Of course, reading glasses may be worn to improve the near
vision for precise or prolonged near tasks
• healing mechanism nay interfare.

25. For your kind attention