17. Pneumatic retinopexy
A procedure for retinal reattachment
Intravitreal gas injection
Transconjunctival cryopexy /
Laser photocoagulation
Appropriate head positioning
18. History
1911 : Ohm, 1ST intravitreal air injection for RD.
1938 : Rosengren, using intravitreal air with
SRF drainage.
1973 : Norton, using intravitreal SF6 with SB or
vitrectomy.
1985 : Blodi, using intravitreal gas for MH with
detachment.
Hilton & Grizzard, using the term “PR”.
1989 : Tornambe & Hilton, comparing PR with SB.
19. Gas Injection
Buoyant Force
Tamponade Effect
Gas occluding retinal break
Preventing fluid influx through the hole
Inferior SRF displacement
Re-absorption of SRF
Retina Reattachment
20. What to inject
Small amount of gas bubble
Expand to required volume
High percentage
N2, O2, CO2
Non toxic
21.
22. types of gas in use
LESS solubility
MORE expansion
Solubility
: C3F8 < SF6 < AIR
Average expansion : 4x : 2x : x
23. Retina – Gas interface
The relationship between
bubble volume & area of tamponade
24.
In normal outflow channels, 20 – 25 % of
vitreous volume may be replaced by gas without
an abnormal rising in IOP.
AIR : ~ 1.2 ml used
SF6 : ~ 0.6 ml used
C3F8 : ~ 0.3 ml used
25.
The most rapid rate of volume expansion
occurs within the first 6- 8 hrs, so IOP should
be monitored during this period.
26.
27.
28. Initial criterias for PR
Size of break : No greater than 1 clock hour
Site of breaks : Superior 2/3 of the fundus
PVR : GR. A or B
Ability to maintain position
No Hx of Severe Glaucoma
No Cloudy media