IC-68: A Video Bouquet of Phaco Complications Which Should Never Have Occurred: With Tips on Damage Control & Prevention to Optimize Postoperative Outcome
Hydrodissection and related complications
Ron Yeoh, Singapore
Hydrodissection is an important but often neglected step in phacoemulsification of cataracts. We hydrodissect in order to mobilize and hence rotate the nucleus for whatever technique of nuclear removal we choose.
The three cardinal signs of adequate hydrodissection are :
1. Fluid wave
2. Anterior movement of the nucleus or nuclear lift caused by the fluid wave passing behind the nucleus. (This also causes the pupil to dilate slightly)
3. Prolapse of the nucleus ( It is important to reposition the nucleus back in the bag if this happens so that phaco can proceed in the anatomical position)
If I see these signs, I do not believe that there is a need to rotate the nucleus.
Problems with hydrodissection
Undoubtedly the most common problem is under-hydrodissection and the surgeon finds that rotation of the nucleus is not possible. One should then hydrodissect once more.
Over-hydrodissection though causes far more morbidity.
I described the ‘Pupil Snap sign of hydrorupture of the Posterior capsule’ many years ago. If hydrodissection is done too vigorously, hydrorupture of the posterior capsule may result with consequent risk of a dropped nucleus. The main clue that a hydorupture has occurred is the observation and familiarity with the pupil snap sign.
As hydrodissection proceeds, it is common that the nucleus lifts upwards, dilating the pupil. The pupil snap sign is seen when this dilated pupil suddenly and briskly constricts; this is the moment that the fluid bolus bursts through the posterior capsule and the nucleus falls back resulting in the pupil constriction. Whether the nucleus stays where it is in the bag, tilts and slides back slowly or drops precipitously depends on factors like size of the tear, pressure in the anterior chamber, state of the vitreous etc. Fortunately it does not always drop immediately. If this sign is recognized, then aborting the phaco and retrieving the nucleus using a vectis salvages the situation and can prevent a nucleus ending up on the macula.