(1)
St. Johns, FL, USA
(2)
Helen Keller Foundation for Research and Education, International Society of Ocular Trauma, Birmingham, AL, USA
(3)
Consultant and Vitreoretinal Surgeon, Milos Eye Hospital, Belgrade, Serbia
(4)
Consultant and Vitreoretinal Surgeon, Zagórskiego Eye Hospital, Cracow, Poland
The endocryo probe used to be standard equipment in 20 g surgery; it was helpful in removing IOFBs or dislocated lens material/IOL. Unfortunately, this tool is not available in MIVS.
Q&A
Q
Is it permissible to use “blind” cryopexy?
A
Although some surgeons still use it over the wound in open globe injuries to “treat invisible or potential future retinal tears,” blind cryopexy is contraindicated. It increases the inflammation, a precursor of PVR; the precise location of the treatment is pure guesswork, and the surgeon knows neither whether his treatment has any effect nor whether he is overtreating.
Transscleral cryopexy today is employed as an adhesion-inducing force in RD surgery as well as a destructive agent in pathologies such as Coats’ disease, vascular tumors and telangiectasias of the retina, and intractable secondary glaucoma.1
29.1 Indication in RD
By causing an inflammatory reaction and the breakdown of the blood-ocular barrier with consequent scarring, cryopexy causes chorioretinal scarring around a retinal break. The confluent spots create a “wall,” which seals the lesion. The scar involves all retinal layers,2 a beneficial effect if destruction is the goal (see below, Sect. 29.3). The scar takes up to a week to develop.
29.2 Surgical Technique
The freezing may be applied over the conjunctiva or directly over the sclera. Ideally, the surface is dried first.
If you have a choice, select a cryoprobe that has a narrow and curved shaft.3
Test the machine: observe whether an iceball forms over the tip of the probe and how many seconds it takes.
Open the speculum to the widest possible and try to avoid touching the lids while freezing.4
Have the nurse activate the machine by stepping on its pedal; you just give clear verbal instructions: “start” and “stop.”
It is preferable that you concentrate on placing the cryoprobe and the freezing effect.
Always have visual control over the intraocular effect.
It is best to perform the cryopexy under the microscope; otherwise, use the IBO.
