Transcript Advanced Contact Lenses

Advanced Contact Lenses
Desinee Drakulich O.D.
Disclaimer
I have no affiliation, nor do I
received financial compensation
from any of the companies or
brands used in this
presentation.
Brief History of Contact Lenses
1508
1823
1887
1939
1948
1971
1978
1981
1986
1987
1987
1996
2002
2002
2010
Leonardo da Vinci illustrates the concept of contact lenses
British astronomer Sir John Herschel conceptualizes practical lens design
First contact lens manufactured from glass, and fitted to cover the entire eye
Contact lenses first made from plastic
Plastic contact lenses designed to cover only the eye's cornea
Introduction of soft contact lenses
Introduction of GP contact lenses
FDA approval of new soft contact lenses for extended (overnight) wear
Overnight wear of GP contact lenses becomes available
Introduction of disposable soft contact lenses
GP contacts available in next-generation fluorosilicone acrylate materials
Introduction of one-day disposable soft lenses
Silicone-hydrogel contact lenses first marketed
Overnight orthokeratology approved by FDA
Custom-manufactured silicone-hydrogel lenses become available
Types of Soft Contacts
Spherical
Aspheric
Toric
Multifocal
Spherical Soft Contact
A spherical contact lens bends light evenly
in every direction (horizontally, vertically,
etc.). They are typically used to correct
myopia and hyperopia.
Aspheric Soft Contacts
Aspheric contact lenses, on the other hand, have
varying curvatures across the surface, changing
from the edge to the center of the lens. This
gradient change of curvature allows for a different
interaction between the lens and light entering
the eye. The bending of light as it enters the eye
through an aspheric lens produces, theoretically,
a clearer image.
Toric Soft Contacts
A toric contact lens has a different focusing power
horizontally than it does vertically, and as a result
can correct for astigmatism. Because a toric lens
must have the proper orientation to correct for a
person's astigmatism, a toric contact lens must have
additional design characteristics to prevent the lens
from rotating away from the ideal alignment. This
can be done by weighting the bottom of the lens or
by using other physical characteristics to rotate the
lens back into position. Some toric contact lenses
have marks or etchings that can assist the eye doctor
in fitting the lens.
Toric Designs
LARS
Rotation
Right Eye
-1.50-1.25 x 090
Left Eye
-2.00-1.25 x 110
Remember LARS
Left Add
Right Subtract
Rotation
Right Eye
10 ‘
Left Eye
10 ‘
-1.50-1.25 x 090
-2.00-1.25 x 110
-1.50-1.25 x 100
-2.00-1.25 x 100
Multifocal Soft Contacts
 Different types of lenses that give two or
more focal pts
Monovision
Bifocal
Modified Monovision
Concentric Ring Multifocal
Simultaneous Viewing Multifocal
Monovision Soft Contacts
 Probably the oldest method of correcting
both distance and near with a soft
contact. It is simply correction the
patients dominate eye for distance and
their non-dominate eye for near.
 Advantages – easy to calculate, less expensive,
patient doesn’t have to change current brand of
contacts and can be used for patients with
astigmatism
 Disadvantages – when the difference between the
two eyes gets too large the patient will loss some
depth perception. Only works for about 70% of
people.
Monovision
Distance
Near
Bifocal soft contacts
 This was a simple design of near center
focal point lens. Simply the center of the
lens was corrected for near and the other
part of the lens was corrected for
distance.
 Advantages – excellent near vision
 Disadvantages – poor distance vision, didn’t correct
for astigmatism
Bifocal soft contact
Modified Monovision
 Took the technology of monovision and
bifocal design and merged them together.
The dominate eye was corrected with a
distance center, near peripheral contact
and the non-dominate eye was corrected
with a near center, distance peripheral
contact.
 Advantages – gave clearer distance vision in most
people. Does have an astigmatic version.
 Disadvantages – still slightly reduced depth
perception.
Modified Monovision
N
D
Dominate Eye
Non-dominate Eye
Concentric Ring Multifocals
This contact lens design uses
multiple rings of distance and near
vision to create multiple focal
points.
 Advantages – usually give better distance and
near vision. Generally doesn’t reduce depth
perception.
 Disadvantages – tend to be more expensive
Concentric Ring Multifocal
D
N
Simultaneous Viewing Contacts
 This design utilizes the fact that light travels in
parallel rays so when the patient is looking straight
ahead the parallel light rays create a distance focal
point and when the patient is converging to see
near the parallel light rays create a secondary near
focal point.
 Advantages – the patient never see both focal points
at the same time so distance and near vision tend to
be very good. Depth perception is not affected.
 Disadvantages – expensive and don’t work for
astigmatic corrections.
Simultaneous Viewing Contacts
Light Rays
N
D
Rigid Gas Perm Lenses
 Not as popular now as they were in the
1970’s and 80’s
 Uses a rigid or hard material to give the
corneal a new spherical surface.
 Many different types depending on the
patients visual needs.
 Because they do not conform to the front
surface to the cornea like a soft lens
design and fitting perimeters must be
calculated properly to ensure patient
comfort and vision.
Types of Hard Contacts
Spherical
Aspheric
Bi-Toric (Back or Front)
Multifocal
Specialty (semi-scleral, scleral and
hybrid)
Ortho - K
Spherical and Aspheric
 Can be used for patients with > 2.00 D of
astigmatism.
 They work by using the patients own tear
film to fill in small amounts of
astigmatism.
 Generally can be fit with a small diameter
lens between 8.7 to 9.6 diameter.
 Generally give very clear distance vision
Spherical and Aspheric
Bi-Toric (Front or Back)
 Bi-Toric rigid gas perms can be used for
patients with >2.00 D of astigmatism.
 Which lens you choose depends on the
location of the astigmatism.
 If the astigmatism is corneal or residual
determines which lens to use. This is
often calculated by the manufacturing lab.
Bi-Toric RGPs
Multifocal RGPs
 The back surface provides an add value of
approximately +1.50 with additional add
power generated on the front surface in
+0.50 increments to a combined
maximum add power of +3.00.
 These lenses can also be used for patients
with astigmatism.
 Similar to the soft contacts these come in
different designs.
Different types of multifocal RGPs
Specialty RGPs
 In general these lenses are used for people who have
irregular corneas.
 Causes of irregular corneas.
 Keratoconus – a degeneration of the cornea causing
thinning usually in the inferior nasal portion of the cornea.
 Ectasis – thinning of the central cornea secondary to lasik
surgery.
 Irregular surface from RK
 Pellucide degeneration – like keratoconus except more
inferior including a much large area of the cornea.
 Post Graph – for people who have had corneal transplants
Rose K RGPs for Keratoconus
Three primary types of Rose K lenses
Rose K (dia: 8.5 to 9.6) for nipple cone
Rose K2IC (dia: 10.5 to 11.2) for large oval cone
RK Reverse geometry (10.5 to 11.2) for post graph
Jupiter lenses for Keratoconus
 A large scleral contact usually between
15.6 and 18.0 diameter.
 Give maximum vision and comfort for
people with irregular corneas and dry eye.
 Generally fit using an OCT scan to
visualize the corneal clearance.
Scleral RGPs
Hybrid RGPs
 Hybrid lenses were developed to give the
exceptional vision of an RGP with the comfort of a
soft contact.
 The first models had a soft contact with slits in the
front surface to insert a RGP. This model didn’t
give great distance vision. (Flex Lens)
 The second model fused a soft skirt around a
center RGP. This gave much better vision and
comfort but the design was flawed which made
removal very difficult. (Synergeyes).
 The third model was similar to the second,
however, the skirt was modified to make removal
easier. This lens is also available in a bifocal design
(Duette)
Hybrid lenses
Ortho – K Lenses
 Design to flatten the cornea while you
sleep.
 A temporary solution to nearsightedness
and small amounts of astigmatism.
 Advantages – no need for contacts or glasses during
the day.
 Disadvantages – expensive, temporary,
uncomfortable to sleep in and only good for
nearsightedness between 1.00D to 6.00 D with
astigmatism less the 1.25 D.
Ortho – K Lenses
Thanks You
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questions