Silicone hydrogel contact lenses, introduced in 1999, significantly increase oxygen permeability compared to traditional soft lenses, promoting better eye health and comfort. They are available in various types and materials, including spherical, toric, and bifocal, and are suitable for extended wear. While generally more expensive and potentially attracting lipid deposits, their benefits often outweigh the drawbacks for many users.

1. SILICONE HYDROGEL
CONTACT LENSES
Optom Muhammed Shareef EK
Bejan Singh Eye Hospital

2. What is silicone hydrogel CL..??
• Soft contact lenses were made possible in the 1960s
and 1970s These were called "hydrophilic gels" or
simply "hydrogels.
• Silicone Hydrogel contact lenses are literally a breath
of fresh air for eye care patients. Brought onto the
market in 1999,
• Silicone hydrogels are the latest in a line of
developments aimed at increasing the oxygen
permeability (increased comfort, longer wear and
better eye health), wettability (better comfort)

3. • Silicone has higher oxygen permeability,
allowing more oxygen to pass
• They are healthier than conventional soft
lenses because they allow up to 6 times more
oxygen to pass through them and increased
oxygen transmission results in better overall
eye health.

4. Characteristics of Silicone Hydrogel
Lenses
1. Modulus
2. Oxygen Permeability
3. Wettability

5. Modulus
• When we speak about the characteristics of silicone
hydrogel materials, the term, “modulus” is often used.
• It describeshow well a material resists deformation.
• Most silicone hydrogel lenses have a relatively high
modulus compared with hydrogels.
• The ease-of-handling and excellent durability imparted
by the higher modulus of silicone hydrogels make them
a good choice for patients who have had difficulty
inserting hydrogels.
•

6. Oxygen Permeability
• Hydrogels have a maximum Dk value under 40
• Current silicone hydrogels range from 60 (Dk/t
86) for Vistakon’s ACUVUE® ADVANCE™ to 140
(Dk/t 175) for CIBA Vision’s NIGHT & DAY®.
• All current silicone hydrogel lenses except the
ACUVUE® ADVANCE™ have Dk/t values of at least
100 and are FDA-approved for extended wear.
The ACUVUE® ADVANCE™ lens, with a Dk/t value
of 86, is approved for daily wear only

7. • Clinical signs of oxygen deficiency with
hydrogel materials include
1. conjunctival injection
2. Limbal redness
3. Neovascularization
4. Corneal edema
Etc….

8. Types of Silicone Hydrogel Contact
Lenses
• There are three types of silicone hydrogel
lenses available. They are spherical, toric, and
bifocal.
• Patients can choose from daily disposals, six-
day extended wear, two-week daily wear, or
thirty-day continuous and daily wear lenses.

9. Materials
• These come with technical names such
as
1. Galyfilcon
2. Senofilcon
3. Comfilcon
4. Enfilcon
5. Lotrafilcon

10. • Silicone hydrogel contact lenses sometimes are
erroneously called silicon hydrogel lenses.
• Silicon is a very common mineral. In fact, ordinary
sand is composed primarily of silicon dioxide.
• Silicone is the name of a group of flexible, plastic-
like materials that contain silicon, carbon, oxygen
and other chemicals.
• In addition to its use to increase the oxygen
permeability of contact lenses, silicone is used to
make breast implants, medical tubing and other
medical devices

11. Advantages of silicone hydrogel CL..
• More resistance to protein deposits
• Less drying of the lenses
• Lower risk of eye infection
• Easier handling due to increased rigidity of
material
• And much lower incidence of complications
with extended wear use (overnight wear)

12. Indications
• People who wear their lenses for more than
12 to 14 hours a day.
• Kids and teenagers who tend to routinely over
wear their lenses.
• Since the Focus Night & Day as well as the
PureVision lenses are approved for 30 days of
continuous wear, they can be considered as a
useful alternative for people contemplating
refractive surgery.

13. • Especially useful in the following types of
patients: people with high prescriptions
• Those whose eyes show signs that they
require more oxygen
• Wearers who experience end of day
discomfort
• Dryness
• Redness with their conventional soft lenses

14. • All contact lenses reduce the amount of oxygen that
reaches the front surface of the eye to some degree.
• When the cornea's oxygen supply is significantly
reduced — a condition calledhypoxia
• Hypoxia-related eye problems became a significant
issue in the 1990s when extended wear contact
lenses first gained popularity.
• Silicone hydrogel lenses were introduced in hopes of
decreasing hypoxia-related problems and increasing
the safety of both daily wear and extended wear of soft
contact lenses.

15. Brands..
• The current brands of spherical silicone
hydrogel lenses available, in order of highest
oxygen transmissibility to lowest, are:
• Ciba Focus Night & Day which is approved for
30 day continuous wear

16. Coopervision Biofinity

17. • Coopervision Avaira; at this time approved
only for daily wear and two week
replacement.

18. • Vistakon's Acuvue Oasys which is approved for
2 week daily wear use or 6 night extended
wear and is designed to be more wettable
than the others and is therefore beneficial for
people who have dry eyes

19. • Ciba's O2 Optix which is approved for 6 days
continuous wear or 2 weeks daily wear

20. • Bausch & Lomb's PureVision which is
approved for 30 days continuous wear

21. • Vistakon Acuvue Advance which is a 2 week
disposable lens and has not yet been
approved for extended wear.

22. Toric SH CL
• There are also currently two toric silicone
hydrogel lenses on the market:Bausch &
Lomb PureVision Toric is a silicone hydrogel
toric lens approved for 30 days extended wear
use

23. • Acuvue Advance For Astigmatism – currently
approved as a 2 week daily wear lens.

24. Ciba Airoptix for astigmatism

28. Contra indication..??

29. Contra indication
• Silicone hydrogels may not be the lens of
choice for all patients
• These lenses are generally more expensive
than non-silicone lenses
• So a more price conscious consumer may not
prefer this option.
• In some wearers, the silicone material tends
to attract more lipid deposits, which may
cause blurred vision and discomfort

30. • There are some cases where a patient is not
able to adapt well to the more rigid silicone
material, which may result in some minor
defects to the corneal integrity.
• These complications are rare and generally the
health advantages and increased comfort that
most wearers experience.

31. Thank You…!!