informative regarding different types of multifocal iols and there use at respective conditions...

1. MULTIFOCAL IOLs
Dr. L.Venkatesh

2. History of multifocal IOLs
• Hoffer in 1982 was the first to hit upon the idea of a
multifocal IOL after observing a patient who had 6/6
vision in spite of an IOL that was decentred by more
than 50% of the pupillary area.
• Logistic problems prevented him from being the first
surgeon to implant bifocal IOL.
• The credit goes to Dr. John Pierce in 1986 who was to
implant the bull’s eye style of the multifocal IOL

3. Type of Multifocals
There are mainly 3 types of multifocal:
1. Refractive
2. Diffractive
3. Combination of diffractive & refractive

4. Refractive optics Multifocal IOLs
• These IOLs, also termed as bulls eye design lens,
have concentric rings of different powers
• This lenses, using concentric zone philosophy are
available in two styles
1. Two Zone Lenses.
2. Annulus type or Bulls Eye lens

6. Two Zone Lenses.
• This have a central near vision segment surrounded by a
distant vision segment and so also may be called a bifocal
IOL
• Since the pupil constrict during near focus, the section is
about 2mm in diameter.
• Optimally when the pupil dilates during distant
viewing,the peripheral distant segment is exposed.
• This design have a disadvantage in bright sunlight,

8. • Since the constricted pupil blocks the distant
segment of the lens.
• It is those poorly tolerated by the pupils who enjoy
out door sports in which clear vision is required.

10. Annulus or bulls type

11. Annulus type or Bulls Eye lens
• The pupil constricts not only during near tasks but also
for distance visual tasks in bright light.
• Therefore,, it becomes imparative that the central zone
must function for both distant and near.
• Those, in annulus design multifocal IOLs, the central
portion of the optics contains the distance vision
refraction and there is near vision ring outside it, which is
inturn surrounded by a another distance vision ring.

12. • With this lens style, even marked pupillary
constriction allows distance vision and mild
contriction allows distance and near vision.
• And all the three lens segments are exposed when
the pupils are dialted.
• However, excessive constriction during reading in
bright light blocks the add portion of the lens, those
preventing clear near vision.

13. Diffractive optics Multifocal IOLs
• In these lenses, the near and distance correction
is kept in each of the concentric rings, during
diffraction optics.
• The diffractive optics utilises the principle of
wavefront optics of light.

14. • The diffractive optic lens combins the standard
convex curvature placed on the front surface with
approximately 25 concentric annular zones cut on
the posterior surface with microscopic steps
between co terminus annuli

18. • The step height is in the range of wavelength of light.
• Such a lens design produces two diffractive orders in
which the incoming waves of light will be in phase,
resulting in discrete optical foci of equal intensity.
• Actually 82% of light is found in two major
foci(approximately 41% of light is in Phase and
focused for near vision and the another 41% is in
Phase and focused for distant vision).

19. • The remaining 18% is lost.
• This diffractive optical effect is present at all points of
the lens.
• Thus,even if the lens is decentred or pupil is
eccentric or deformed,the protion of the lenses
within the pupil will supply power for distance and
near vision.

23. CONCEPT OF APODIZATION
• The concept of apodization is that of a gradual
transition of optical properties from centre of
a lens to its egde.

24. Disadvantages of Multifocal IOLs
1. Reduce light intensity
2. Reduced contrast sensitivity
3. Off axis aberration
4. Perception of rings
5. Glare and halos

25. 1. Reduce light intensity
• The light intensity entering the eye is halved.
Thus, the greatest optical disadvantage of
multifocal IOLs, In general, is that even in the
ideal situation not all the light entering the eye
reaches the retina in focus for either near or
distance vision, as:
i. In bulls eye lenses:- The amount of the light
transmitted for each of the focal lenghts varies
with pupil size. Therefore, distant and near
objects may be of different intensities

26. ii. Diffractive optic IOL:- The image intensity is
equal for near and distance vision, but even
in the ideal situation, only one half of the
light entering the eye is in focus.

27. 2. Reduced contrast senstivity:
• contrast senstivity is decreased in multifocal iols as
compared to conventional IOLs,obviously bec’os of
decreased intensity of the light focused..
• Moreover,even more light may b lost due to
scaterring,further decreased retinal image contrast.
• Patients with MFI need somewat brighter light to
read well,and generally functional less well in dim
light.

28. 3.off axis aberrations:
• in decentred IOLs create more problems in multifocal
IOLs as compared to conventional IOLs.
• Although both bulls eye and diffractive IOLs require
excellent centration,it is more critical with diffractive
lenses since they suffer stronger off axis aberration.
4.Perception of rings:
• around point sources of light is another
problem faced with the use of multifocal IOLs

29. • Less satisfactory visualization of fundus-
difficulty in vitreo retinal procedure.
• Requires visual cortical- neuro adaptation

30. PATIENT SELECTION
• B/L implantation
• Postopertive astigmatism <0.75D
• Postoperative emmetropia or max <0.75D hyperopia.
• Patient motivation(high diopter
glasses,hyperopia,spectacle independence).
• No glaucoma and ARMD pathology.
• hobbies like painting, playing the piano, playing cards or
billiards or is he just the unusual avid reader?

31. • Age group of 40 to 70 yrs of age.
• Occupational night drivers –For all these patients
even ashort term glare or halo effect will be
intolerable.
• Counseling these patients and explaining them about
potential side effects and also the fact that they are
easily tolerable with binocular summation and lessen
with time is very crucial

33. NOT SUITABLE
• Significant dry eyes
• Corneal scarring
• Pupil size <2.5mm
• Monofocal implant in one 1 st eye
• Uncorrected postoperative astigmatism >0.75D
• Unstable capsular support
• ARMD,glaucoma with severe visual field loss.
• Someone who demands perfect vision

34. • Retinal problems which may have already decreased
the contrast sensitivity, may not be ideal candidates.
• History of previous Refractive Surgery-Although
these patients are the most strongly motivated ones
to have multifocal lens implants they may be
unsuitable.
• If K readings are < 40 one should suspect this
possibility.
• Biometry accuracy is not always possible in these
patients and clinical correlation with previous or
present spectacles along with the pre-refractive
surgery keratometry is important if a multifocal IOL is
planned.

37. Rezoom multifocal iol

38. • Its a refractive type multifocal iol
• Resembels the annulus type design n function
as such as that of annulus type.
• Common concerns are monoocular
diplopia,halos at night n object glow.

40. Acrysof restor

41. • It is a diffractive type multifocal iol
• Silicone material
• Uses ‘apodization’ to soften blur and sharpen
vision
• Provides excellent VA at near,distance n
intermediate ranges.

42. Acrysof restor

43. Tecnis multifocal

45. • Diffractive type multifocal iol
• The Tecnis IOL (Advanced Medical Optics, Inc., Santa
Ana, DA) represents the first IOL that has a
wavefrontdesigned, modified prolate, anterior-surface
optic that neutralizes the positive spherical aberration
of the human cornea.
• Its design is based on the average corneal-surface
wavefront-derived spherical aberration in a group of
patients, and the optic neutralizes this aberration.
• Spherical aberration is the human optical system, and
it increases throughout life to continually decrease
visual quality. Implanting conventional spherical IOL
optics not only fails to address this problem but also
contributes to it. The implantation of the Tecnis IOL can
significantly reduce spherical aberration in
postoperative cataract patients.

46. Rayner M flex multifocal

48. • It is a multizoned,refractive ,aspheric
multifocal intraocular lens.
• Indicated for those patients requiring a degree
of pseudoacommodation

49. Combining Refractive & diffractive
IOLs
• Refractive IOLs such as the AMO ReZoom lens offer
excellent intermediate and distance vision as well as 100%
transmission of light.
• Incoming light is directed across the entire focal plane of the
lens to provide vision at all distances.

50. • However, near vision is not as strong with these
lenses as with some other technologies, so patients
may have more difficulty reading up close.
• These lenses are also pupil dependent, so there may
be mild night-vision symptoms.
• Refractive lenses are ideal for light to moderate
readers who drive mostly during the day

51. • Patients who play sports, use a computer frequently,
or enjoy activities such as playing cards activities that
all rely heavily on intermediate vision will benefit
from refractive lenses.
• Diffractive IOLs such as Alcon’s ReSTOR lens and
Advanced Medical Optics’ Tecnis Multifocal IOL offer
excellent near and distance vision as well as good
reading speed.
• They are pupil independent, so patients experience
fewer problems with night vision.

52. • However, there is a, gap in intermediate
vision as well as a loss of transmitted light and
therefore, a loss in contrast sensitivity with
these lenses.
• Diffractive lenses are ideal for patients who
spend a lot of time reading or doing detailed
craft-work.
• Those who like to go to the movies and those
who often drive at night are also good
candidates for these lenses because they
function independently of pupil size.

53. • However, not all patients fit neatly into one
category.Some individuals love sports and movies.
• Others aren’t big readers but often drive at night.
Studies have been done compare the results of
bilateral implants of the same IOL to a mix-and-
match diffractive/refractive.
• Mixing and matching different IOLs allows the
surgeon to combine the advantages of both
refractive and diffractive lens technologies

55. THANK YOU