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2. These are gases or liquids which are used as intra operative
instruments to reestablish intraocular volume, to assist in
separating membranes adherent to retina, to manipulate retinal
detachment and to mechanically flatten retina.

3.  The vitreous humor occupies 2/3rd of the volume of the eye.
 Is a gelatinous substance composed of water (98–99%) &
Matrix of collagen fibers and hyaluronic acid gel.
 Its functions include holding the retina in place and
circulating metabolites throughout the eye.
 This gel is itself is damaged in various vitreoretinal disorders
and needs to be replaced.
VITREOUS HUMOR

4.  Good tamponade effect
 High surface tension
 Sufficient buoyancy
 Should be inert, slowly biodegradable and transparent
 Maintain stable refractive index and shock absorbing properties
 Avoid serving as a scaffold for cellular proliferation
Expected to have :

5. Conventional
• Air – SF6, C3F8
• Liquid – BSS, Perfluorocarbons,
Silicon oil
Newer
• Semifluorinated Alkanes
• Silicon oil-semifluorinated alkane
combination
Experimental
• Polymers – Hydrogel, Smart
Hydrogel, Thermosetting gels
• Implants
• Cell culture

6.  Used as irrigation fluid during vitrectomy and also to maintain
normal intraocular volume and pressure after drainage of SR
fluid during RD surgery & choroidal detachment.
 BSS enriched with bicarbonate, dextrose & glutathione
better tolerated by ocular tissue, especially endothelium
BASAL SALT SOLUTION

7.  It offers no tamponade effect
 It may pass through retinal breaks & may lead to
RD
BSS not preferred because

8.  Ohm(1911)-
1stintravitreal air
injection for RD
 Rosengren(1938)
concept of internal
gas tamponade
 Norton(1973)
reported favorable
results with SF6
Air & other gases

9. Buoyancy
Surface
tension
Interruption
of intraocular
current
Intra ocular air bubble is based on 3 features

10. Non expandable
• Air
• Nitrogen
• Helium etc.
Expandable
• SF6
• C3F8

11. Three phases of gas transfer in expanding gases

12. Bubble expansion

13. Nitrogen equilibrium

14. Bubble diffusion

15.  First gas to be injected intravitreally
 Effect lasts for 3 days
 Can be used in RD to maintain IOP after SRF drainage
 Now not used commonly as internal tamponade
Air

16.  Expandable gas
 Colourless, odourless, nontoxic gas
 Max expansion after 36 Hrs (doubles in volume)
 Disappears in 10 days
 It was shown that this inert gas provided longer, more
effective tamponade than air
 Relatively free of harmful side effects
Sulfur hexafluoride

17.  Inert, colorless & inflammable
 6 times heavier than air
 Max expansion occurs after 2 days – 4 times the initial volume
Perfluorocarbon gases

20. Indications
• Presence of superior retinal detachments that do not have too much subretinal fluid
• Retinal breaks occurring from the 10 to 2 o’clock meridians
• Breaks in the periphery between the ora serrata and the equator
• Macular holes & other posterior retinal breaks
• Re-detachment after scleral buckling
• Contra-indications to GA

21. Contraindications
• Inferior breaks
• PVR – pre op traction on retinal tear
• Inability to maintain appropriate position
• Severe glaucoma
• Cloudy media- precludes full assessment of retina
• Aphakia / pseudophakia with PCO
• If patient has to travel by air within 1 week

22. Postoperative Care
Clinical Estimation of Gas Volume
• Patient must maintain prone or particular head position after gas injection
• IOP should be measured 6-8 hrs post operatively
• Prophylactic timolol/acetazolamide is indicated
• Most clinicians describe “gas fills” as a percentage of the vitreous cavity
based upon ophthalmoscopy

23. Complications
• Pupillary block glaucoma
• Corneal endothelial decompensation
• Shallow AC
• CRVO
• Expansion during air travel
• lens opacity
• Subretinal gas migration
• Dislocation of IOLs

24. Gas Pulling on the Vitreous and Retina Leading to
Hemorrhage and Tears and Shifting of Subretinal
Fluid to Macular Area

25. Air CF4,SF6 XE Perfluorocarbons
Choice of gases
• When the volume of gas is adequate to tamponade the break
• when its desirable to achieve larger bubble size to tamponade multiple retinal breaks or folds
• when large volume of SRF is drained
• when greater expansion properties are needed –GRT, macular holes

26. • Sodium hyaluronate (1%; Healon) has the most
favorable viscoelastic properties
• Used to unfold the retina during repair of giant retinal
tears and to manage hemorrhage
• Also used in separation of epi-retinal membranes*
VISCOELASTIC SUBSTANCES

27. Cibis et al(1962)-
silicone oil in
retinal Surgery
“Silicone oil”-
“lighter than
water”
“Fluorosilicone”,
“heavier than
water”
SILICONE OIL

28. • Clear, transparent, inert, non carcinogenic, heat resistant
• High surface tension
• Immiscible in water
• RI – 1.404
• Lighter than water
PROPERTIES OF SILICONE OIL

29. Tamponade Space filler Mechanical inhibition of
membraneous contraction
Haemostasis
MODE OF ACTION
• Acts as internal permanent tamponade in attaching traction free RD*
• immiscibility of waterlimits free movts of proliferative cells & biochemical mediators within
vitreous*
• Inhibits diffusion of angiogenic mediatorshelps in rubiosis iridis
• redirects tractional forces from radial to tangential traction so re-detachments are usually fla
confined to periphery sparing macula
• Tamponades bleeding vessels in PDR and from the edge of retinotomy & retinectomies

30. Optics
In Phakics & Pseudophakics
In Aphakics
• Concave anterior surface of the globule it causes hypermetropia of about +5D
• Convex anterior surface of the globule power of the eye is increased such that the
aphakic refractive error (pronounced hyperopia) is reduced

31. • Long-term tamponade of the retina
• PVR
• Giant retinal tear
• PDR
• Traumatic RD
• RD complicated by iris neovascularization
• Patient not compliance with positioning & post op positioning
• After failure of previous scleral buckling, vitrectomy, membrane dissection &
intraocular gas injection for Rx of RD
INDICATIONS

32. Emulsification
COMPLICATIONS

33. Cataract

34. Band shaped keratopathy

35. Stromal opacification

36. Glaucoma
• Immediate post op rise due to inflammation
• Acute pupillary block in aphakics- prevented by inferior (Ando’s/Japanese) iridectomy
• Emulsified oil trapped in TM chronic glaucoma

37. Silicon Syndrome

38. Hypotony
• Retinopathy (toxic) -not proved
• Redetachment after removal of silicone oil

39. • PFC were first evaluated as artificial blood substitutes
• Haidt et al.(1983) first used PFC experimentally as a vitreous substitute
• Colorless, odorless, non-flammable
• Chemically and biologically inert when pure.
• They are stable to temperatures as high as 400 to 500º Celsius.
• High specific gravity*
• Significant tamponading effect*
PERFLUOROCARBON LIQUIDS

40. • Optically clear
• Immiscible with water or blood or other common organic compounds
• Low viscosity*
• High vapor pressure rate
• Refractive index significantly different from aqueous

41. Optical Clarity
• All PFC liquids are optically clear and relatively free of sources of reflection/optical aberratio
• optical clarity allows the application of laser energy to the attached retina during the surgica
• Since they do not absorb visible light and have a higher boiling point than the thermal burn,
PFC liquids are considered a safe medium for the delivery of laser energy

42. Immiscible with Intraocular Fluids
• The ability of the material to resist incursion by blood or intraocular fluids makes it a valua
in improving visibility in cases involving heavy or uncontrolled bleeding.
• PFCL can also be used as a “unit”, making them helpful in retrieving intraocular or crystall
lenses by floating them off the retina and up into the pupillary space.

43. Refractive Index
• The ability to accurately control intraoperative PFC liquid is dependent on the surgeon’s ability
the material in the eye. PFCL have an index significantly different than aqueous. Hence,
a distinct interface between the perfluorocarbon liquid and aqueous can be clearly visualized.
• Also helps to remove the PFC at the conclusion of surgery.

44. Injected slowly keeping the tip of the cannula just within the meniscus of the
expanding bubble, and centered over the optic disc if it is visible.
Administration of PFCL

45. • Giant Retinal Tears*
• Proliferative Vitreoretinopathy(PVR)
• Trauma
• Dislocated Lenses
INDICATIONS

47. Dislocated Lenses
• The specific gravity of perfluorocarbon liquids is greater than that of crystalline
lenses, PMMA (IOL’s) or silicone intraocular lenses, and allows the surgeon to
gently float the
dislocated lens or fragment off the retina following a “complete” vitrectomy,

48. • Retinal detachments secondary to macular holes can be managed by injecting a
small amount of PFCL to flatten the hole so that endophoto-coagulation can be
carried out
• Surgical Management of retinal detachments in advanced ROP
• Endophthalmitis: PFCL can be injected to cover posterior pole during vitrectomy for
endophthalmitis, which prevents contact of the antibiotic with macula, avoiding
possible macular toxicity

49. • Control of Bleeding During Pars Plana Vitrectomy
• Removal of Intraocular Foreign Bodies

50. • Retinal break from forceful injection of PFCL into the vitreous cavity*
• Dispersion of PFCL into multiple bubbles can occur if the level of PFCL goes
above the infusion cannula or if injection is not done into the PFCL bubble
• Large amount of PFCL can damage the corneal endothelium in aphakic and
pseudophakic eyes and should be removed completely
Complications

51. • Useful in the treatment of complex retinal detachments. Such a combination
supports both superior and inferior areas of the pathology
• Silicone oil greater viscosity is less likely to enter the anterior chamber
in aphakic eyes than are PFCLs & resist the movement of PFCL into the
anterior chamber
• Silicone oil tends to delay the emulsification of PFCLs when both are used
together
Combination of PFCL and Silicone oil

52. Experimental
• Polymers – Hydrogel, Smart Hydrogel, Thermosetting gels
• Implants
• Cell culture