2. PRESENTATION LAYOUT
HISTORY
INTRODUCTION
RHEOLOGICAL & PHYSICAL PROPERTIES
COMPOSITION
CLASSIFICATION
CLINICAL USES
COMPLICATIONS
DR PRAVIN RAI 2
3. HISTORY
◦ Sodium Hyaluronate was 1st used in
ophthalmic surgery in 1972 as a
replacement for vitreous and aqueous
humor.
◦ Viscosurgey was term coined by Balazs in
1979.
◦ Healon (sodium hyaluronate, 1%) is the
first viscoelastic product produced in1979.
DR PRAVIN RAI 3
4. INTRODUCTION
Viscoelastic agents (now termed ophthalmic
viscosurgical devices [OVDs] by the International
Standards Organization [ISO]) for uses in ophthalmic
intraocular procedures has had a significant impact
on
the practice of ophthalmology.
Ophthalmic viscosurgical devices (OVDs), are a
class of nonactive, clear, gel-like chemical
compounds with viscous and elastic properties.
DR PRAVIN RAI 4
5. OVDs possess a unique set of properties,
on their chemical structure, that enable
them to protect the corneal endothelium
from mechanical trauma and to maintain
an intraocular space, even in the face of
an open incision.
DR PRAVIN RAI 5
6. Ideal Viscoelastic
Ease of infusion
Retention under positive pressure under eye
Retention during phaco
Easy removal/ no removal needed
Doesn’t interfere with instruments/ IOL placement
Protects endothelium
Nontoxic
DR PRAVIN RAI 6
8. VISCOSITY
Viscosity reflects a
solutions resistance to
flow.
Viscosity of OVDs is
measured in
centipoise(cPs) or
centistokes (cSt), which
are measures of the
resistance to flow relative
to given shear force.
The higher the solutions
molecular weight, the
more it resist flow. DR PRAVIN RAI 8
9. VISCOELASTICITY
Elasticity refers to
the ability of a
solution to return to
its original shape
after being stressed.
Elasticity allows the
anterior chamber to
reform after
deformation by
depression on
cornea when
external forces are
released.
DR PRAVIN RAI 9
11. PSEUDOPLASTICITY
Pseudoplasticity refers
to a solutions ability to
transform when under
pressure, from a gel
like substance to a
more liquid substance.
More pseudoplastic a
material is, more
rapidly it changes from
being highly viscous at
rest to a thin, watery
solution at high shear
force.
DR PRAVIN RAI 11
12. SURFACE TENSION
The coating ability of OVD is
determine not only by
surface tension of material
itself but also by a surface
tension of contact tissue,
surgical instruments or IOL.
By measuring the angle
formed by drop of OVD on a
flat surface ( contact angle)
the coating ability is
estimated.
At lowest surface tension
and lower contact angle,
better ability to coat. DR PRAVIN RAI 12
14. SODIUM HYALURONATE
Biopolymer, disaccharide
Occurring in many connective
tissues through the body
including both aqueous and
vitreous humors.
Hyaluronate has a half life of
approximately 1 day in aqueous
and 3 days in vitreous.
Mainly present in visco
cohesive.
DR PRAVIN RAI 14
15. CHONDROITIN SULFATE
Chondroitin sulfate is another
viscoelastic biopolymer that
is found as one of the three
mucopolysaccharides in the
cornea.
Obtain from shark fin
cartilage
Estimated from anterior
chamber is approximately 24
to 30 hours.
Coats tissue but poor space
maintainer
DR PRAVIN RAI 15
16. HYDROXYPROPYL METHYL
CELLULOSE
Does not occur naturally in animals but is
distributed widely in plant fibers.
Easy availabiliy
Ease of preparation
Storage at room temperature
Ability to withstand autoclaving
Main component in dispersives
DR PRAVIN RAI 16
17. HYALURONATE PRODUCTS
Healon, Healon 5, Healon GV
Amvisc, Amvisc plus, Provisc
HA+ CA PRODUCTS
Viscoat, Discovisc
HPMC PRODUCTS
Ocucoat, Cellugel
DR PRAVIN RAI 17
18. CLASSIFICATION OF OVDS
1
• High Viscosity- Cohesive
OVDs
2
• Lower viscosity- Dispersive
OVDs
3
• Viscoadaptive OVDs
DR PRAVIN RAI 18
19. COHESIVE VS DISPERSIVES
COHESIVES DISPERSIVES
High viscosity
High Mol Wt
Long chain
molecules
Adhere to themselves
through
intermolecular bonds,
resists breaking apart
High degree of
pseudoplasticity and
high surface tension
Low viscosity
Low mol wt
Short chain molecules
They adhere well to
external surface, e.g.-
tissues and
instruments. These
materials tend to break
easily apart.
DR PRAVIN RAI 19
22. HIGH VISCOSITY COHESIVES
• 1- Healon GV
• 2 –Ivsic plus
SUPER
VSICOUS
• 1- Ivisc
• 2-Provisc
• 3-Healon (1%)
• 4- Amvisc
VISCOUS
DR PRAVIN RAI 22
23. All products contain Na. Hyaluronate
Indications of high viscous cohesive
OVD-
•To deepen the AC
•To enlarge small pupils
• To dissect adhesions
•During IOL implantation
DR PRAVIN RAI 23
24. ADVATAGES
1. Maintain space at low shear rates
2. Easily displaced at high shear rates
3. Sticks together, aspirated out easily
4. Low risk of post op IOP rise even if
retained
DISADVANTAGES
- Minimal coating, so less endothelial protection.
DR PRAVIN RAI 24
25. • 1-Viscoat
• 2-Vitrax
• 3-Cellugel
MEDIUM
VISCOSIT
Y
• 1-Ocucoat
• 2-Ocuvis
• 3-Viscilon
VERY LOW
VISCOSITY
LOW VISCOSITY-
DISPERSIVES
DR PRAVIN RAI 25
26. ADVANTAGE
Excellent coating and gives superior endothelial
protection.
DISADVANTAGES
Complete removal of dispersive OVD is difficult
because the molecules do not tend to join together
and do not aspirate as a unit.
Do not maintain or stabilize space.
Can form micro bubbles and obscure the view.
High risk of post op rise IOP rise.
DR PRAVIN RAI 26
27. VISCOADAPTIVES
Behavior change at different flow rates.
Acts as viscous cohesive agent at lower flow
rate and as a pseudo dispersive agent at
higher flow rate.
Adapts its behavior to surgeon needs during
surgery.
Example- HEALON-5
DR PRAVIN RAI 27
28. ADVANTAGES
1) Crystal clear and high refractive index then aq.
Humor, so increase clarity within surgical field.
2) Ability to bind to and to protect delicate corneal
endothelial cells from debris and turbulence during
phaco.
3) Helpful in small pupil as it causes viscomydriasis.
4) Neutralizes the +ve pressure and prevents the
capsulorehexis extension.
DISADVANTAGE
1. Risk of post op IOP rise if retained
DR PRAVIN RAI 28
29. SOFT CELL TECHNIQUE
Developed by Arshinoff.
Use of lower viscosity dispersive and
high viscosity cohesive OVDs together
to minimize their drawbacks and to get
best properties of both.
DR PRAVIN RAI 29
32. USES
Floppy iris syndrome- The soft shell
technique can hold the iris in place throughout
surgery.
Cases of broken zonules- the dispersive
OVD can compartmentalize the eye and keep
vitreous pushed posteriorly, while the cohesive
OVDs keep the anterior chamber formed and
pressurized.
Highly myopic eyes- dispersive OVDs protect
the cornea, while reapplication of cohesive
OVDs to pressurize the anterior segment can
minimize traction on the vitreous base and
DR PRAVIN RAI 32
33. TASK ( SPECIAL CASES) FUNCTION NEEDED Agent Used
Compromised cornea Coating the cornea for
protection
Dispersive
Very shallow AC Main the deep AC Cohesive
Small pupil,floppy iris For opening up the
eyes
Cohesive
Dense cataract Endothelial coating Dispersive
Remove OVD at
inclusion of surgery
Remove quickly and
completely
Cohesive
DR PRAVIN RAI 33
34. USES OF OVDS
CATARACT SURGERY:
Coat and protect endothelium ( direct trauma from
instruments, lens fragments, or air bubbles
,Ultrasound energy from phacoemulsification and
irrigation fluid turbulence)
Maintain anterior chamber (for example, during
capsulorhexis or phaco tip insertion)
Open capsular bag for intraocular lens implantation
Viscodissection/Viscoexpression
Mobilisation of lens fragments
Compartmentalisation of surgical field (for example,
during vitreous loss)
DR PRAVIN RAI 34
35. GLAUCOMA SURGERY
Visco-canalostomy
Means opening of schlemms canal by OVD
A Non penetrating procedure, independent of external
filtration
Advantages
-decrease risk of infection
-decrease the incidence of cataract
-hypotony
- flat AC
- Excludes risk of late infection, conjunctival and
episcleral scarring
Healon GV and healon5 are used.
DR PRAVIN RAI 35
36. KERATOPLASTY
Used to fill the AC before removing corneal
button from donor eyes as it helps to protect
corneal endothelium and provides and even
and circular trephination.
In recipients eyes helps to have even and
circular trephination, protects other
intraocular structures, maintain IOP and
prevents sudden collapse of AC during
trephination.
In lamellar KP helps in the dissection of deep
stroma during dissection of receipents stroma
called viscodelamination of cornea.
DR PRAVIN RAI 36
37. POSTERIOR SEGMENT
SURGERIES
Replace diseased vitreous
Reattach and provide temporary tamponade of
retinal hole and detachments.
Reattach Giant retinal tears or rolled retina.
Restore intraocular pressure after release of
subretinal fluid.
Maintain IOP during vitrectomy
Protect corneal endothelium during gas injection in
aphakic eye. DR PRAVIN RAI 37
38. In Strabismus surgery Force required to
bring the muscle to its insertion is significantly
less with the use of subconjunctival
viscoelastic.
During DCR surgery it helps in identifying
lacrimal sac.
Viscoelastics have role in canalicular
repair where the uninjured canaliculus is
irrigated with the fluorescin dye tinted
viscoelastic, that spills from the other end ;
helping to locate the proximal end of the
proximal canaliculus. DR PRAVIN RAI 38
39. RECENT USES
VISCOSTAINING OF CAPSULE
Dye mixed with OVD called as
viscostaining of ant. Lens
capsule covers ant capsule
without coming in contact with
corneal endothelium.
DR PRAVIN RAI 39
40. VISCO ANASTHESIA
Mixture of OVD with an anesthetic solution( Known as
VISTHESIA) had advantage of viscosurgery,
maintainence of ACD, capsular bag extension,
protecting of corneal endothelium.
Prolongs anesthesia
No extra surgical step for intracameral inj. of lidocaine.
Contains topical component -0.3% hyaluronic acid
with 2% lidocaine in single dose unit.
DR PRAVIN RAI 40
41. REMOVAL OF OVDs
Rock and Roll method
Two compartment technique
Bimanual irrigation and aspiration
technique.
DR PRAVIN RAI 41
42. COMPLICATIONS OF OVD USE
Post op increase in IOP
- occurs in 1st 6-24hrs & resolves
spontaneously within 72hrs.
Crystallization of IOL surfaces
- Due to precipitation or deposition of
viscoelastic solution.
- Fern like or amorphous appearance
- IOL should be explanted and
exchanged.
DR PRAVIN RAI 42
43. Capsular Bag Distention
syndrome(CBDS)
Characterized by accumulation of liquefied
substance within a closed chamber inside
the capsular bag, formed because the lens
nucleus or the PCIOL optic occludes the
ant. Capsule opening created by
capsulorhexis.
Classified as:
1. Intra op- time of nucleus luxation
following hydro dissection
2. Early post-op
3. Late post op- with liquefied after
DR PRAVIN RAI 43
44. Eg- use of high density viscoelstic agent like
Healon GV causes late CBS
Reduced distance visual acuity and improved
near acuity due to induced myopia; forward shift
of IOL.
IOP is normal, despite shallow anterior
chamber.
Treatment is done by YAG laser application to
anterior capsule to allow OVD to escape
anteriorly or posterior capsule may be lasered
with escape of OVD posteriorly.
DR PRAVIN RAI 44
46. Calcific band keratopathy:
- Occurs with chondriotin sulfate containing
OVDs.
Pseudoanterior uveitis:
-Due to OVDs viscous nature & the electrostatic
charge of it
- RBCs & inflammatory cells remain in AC
giving it appearance of uveitis.
-Spontaneously resolve within 3 days
- Intraocular hemorrhage may be trapped
between vitreous space & OVD in AC mimicking
VH.
DR PRAVIN RAI 46
47. Wound Burns
The OVD itself does not cause the
incisional burn; however, OVDs can
trigger temperature increases during
phacoemulsification.
The major contributors to elevated
incision temperature included incision
size, ultrasound power, duty cycle,
vacuum setting, tip design and presence
of an OVD.
This can be avoided by preventing
obstruction of the flow with OVD by
creating a fluid space around the
ultrasound tip.
DR PRAVIN RAI 47
48. Message To Take Home
No single OVDs is ideal under all
circumstances.
A thorough understanding of these
properties will allow ophthalmic
surgeons the opportunity to choose an
OVD that is task specific.
DR PRAVIN RAI 48
50. REFRRENCES
Principles and practice of ophthalmology ,
third edition ,Albert Jackobiec’s.
Fundamentals of Clinical Ophthalmology,
Cataract Surgery, Andrew Coombes and
David Gartry.
New classification of ophthalmic
viscosurgical devices 2005 Steve A.
Arshinoff, J Cataract Refract Surg 2005
Ophthalmic viscosurgical devices,Hiroko
Bissen-Miyajima, Current Opinion in
Ophthalmology 2008
Various internet resources.
DR PRAVIN RAI 50
