If properly executed, hydrodissection is a simple, safe, and an inexpensive method of optimizing the surgical outcome in a routine cataract surgery. After the injection of fluid beneath the anterior capsule, the capsule is decompressed by pressing the central portion of the lens with the shaft of the cannula. This forces the fluid to come around the lens equator from behind and break the cortical/capsular connections in the capsular fornix and under the anterior capsular flap [2, 3]. The cleavage of cortex from the capsule allows fluid to exit from the capsular bag via the capsulorhexis and mobilize the lens in such a way that it can spin freely within the capsular bag [2, 3].

Safe hydrodissection can be achieved by injecting the fluid slowly and decompressing the nucleus after each wave. Apart from this, CCH also helps to control the incidence of posterior capsule opacification (PCO). The shearing effect of the fluid wave created during procedure is believed to be helpful in removing lens epithelial cells (LECs), reducing the incidence of PCO [4–10]. In a study, conducted on human cadaver eyes [9], it was confirmed that this force detaches equatorial LECs from the adjacent equatorial capsule, allowing their easy removal from the eye.

Depending upon the surgeons’ choice, a single-site hydrodissection or a multiple-quadrant hydrodissection can be performed, although the latter is considered to be more effective in obtaining a maximum fluid shear effect [11–13]. Multiple-quadrant hydrodissection also helps break cortical/capsular adhesions, which are commonly associated with senile cataract in the developing world. Some surgeons prefer doing hydrodissection from the paracentesis opening. This can increase pressure buildup within the eye, which can lead to posterior capsule “blowout” or iris prolapse [12]. If the hydro procedures are being carried out through the side port, it is absolutely necessary to use the minimum fluid possible so that integrity of the posterior capsule is maintained. These procedures may be carried out with the anterior chamber maintainer in the on or off position. Certain conditions like high myopes, vitrectomized eyes, traumatic cataract, pseudoexfoliation, posterior lenticonus, and complicated cataracts require undue care during hydro procedures as they are especially prone to develop complications if hydro procedures are not carried out with due precautions.

Various types of cannula are available for performing hydrodissection. They vary from round tip to flat tip. A flat tip cannula allows easy access under the capsule and minimizes fluid egress from the anterior capsular lip as well. It is essential to maintain the flat portion of the cannula parallel with the anterior capsule. The tip of the cannula should be extended peripherally to allow for adequate anterior capsular coverage, ensuring proper posterior delivery of fluid. J-shaped cannula are also available for injection at the subincision site. Also, a cannula with a long shaft facilitates the reach of the cannula at the distal capsulorhexis margin.