Viscoelastic devices, also known as ophthalmic viscosurgical devices (OVDs), are gel-like compounds used in ocular surgery to protect tissues and maintain spaces in the eye. They have unique rheological properties including viscosity, elasticity, and pseudoplasticity. Common compositions are sodium hyaluronate, chondroitin sulfate, and hydroxypropyl methylcellulose. OVDs are classified as high viscosity cohesive agents, lower viscosity dispersive agents, or viscoadaptive agents. They are used in cataract surgery to coat and protect tissues, maintain the anterior chamber, and aid in lens removal and intraocular lens implantation. Complications can include increased intraocular pressure if not fully

1. VISCOELASTIC
DEVICES
DR Pravin rai
1st year Resident
DR PRAVIN RAI 1

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

7. PROPERTIES
RHEOLOGICAL PROPERTIES
Viscoelasticity
Viscosity
Pseudoplasticity
Surface Tension
DR PRAVIN RAI 7

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

10. DR PRAVIN RAI 10

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

13. COMPOSITION
Sodium
Hyluronate
Chondroitin
Sulfate
Hydroxypropyl
Methyl cellulose
DR PRAVIN RAI 13

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

20. DR PRAVIN RAI 20

21. DR PRAVIN RAI 21

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

30. DR PRAVIN RAI 30

31. SOFT SHELL TECHNIQUE
DR PRAVIN RAI 31

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

45. DR PRAVIN RAI 45

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

49. DR PRAVIN RAI 49

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