Goal
The aim of this manoeuvre is to make the incisions watertight at the end of cataract surgery, without the need for sutures. Proper wound hydration ensures that the wound edges coapt and prevents leakage of aqueous humour from the anterior chamber.
Principle
The technique is based on hydrating the interface between the stromal lamellae. Introducing fluid into this layer causes stromal swelling, which presses the wound edges together and provides temporary closure of the incision. The wound subsequently seals spontaneously.
Technique
Choice of cannula
Use a cannula with a round lumen whenever possible.
A round lumen hydrates a larger surface area of the incision wall, resulting in a more uniform effect.
Positioning the cannula
Place the opening of the cannula against the stromal wall, just beneath the epithelium.
The tip should sit firmly in the angle (“armpit”) of the incision so that the fluid spreads within the stromal layers.
Injecting the fluid
Apply firm pressure on the plunger to generate sufficient force.
Correct hydration is recognised by the appearance of a small white, feather-like cloud within the stroma.
Important considerations
- The presence of Descemet folds indicates that the injection is too deep, too close to the Descemet membrane. In this situation, the fluid spreads more centrally and the sealing effect on the incision decreases. A Descemet detachment may also occur.
- Orient the cannula approximately parallel to the limbus. This reduces the risk of accidentally entering the anterior chamber should the cannula detach from the syringe. Such an event may lead to hyphema, capsular rupture, or retinal injury.
How to recognise adequate incision hydration
As mentioned above, correct hydration is indicated by a small, white, feather-like cloud forming in front of the cannula.
When both paracenteses are properly hydrated, the eye should feel firm (“rock hard”). If this is not the case, additional hydration should be performed. The following sequence can be used, with intraocular pressure reassessed after each step. If the tone remains insufficient, proceed to the next step:
- Hydrate one angle of each paracentesis.
- Add more hydration to the same angle of both paracenteses.
- Hydrate both angles of the main incision.
- Hydrate the opposite angles and the roof of the paracenteses.
- Use fluorescein to identify any persistent leak.
- Place a suture on any incision that continues to leak.
Hydration of the anterior stroma just beneath the epithelium. The cannula is kept parallel to the limbus
