Be prepared for pupil snap during phacoemulsification
Pupil snap, described by Dr. Ronald Yeoh, is an ominous sign during a phacoemulsification procedure, marking the breakage of the posterior capsule followed by momentary constriction of the pupil, like a quick snap, as seen in Figure 1.
Performing hydrodissection is an important step during phacoemulsification. Multiple quadrant hydrodissection helps to diffuse fluid evenly, forming a good cushioning effect for the nucleus and thereby separating it from the capsule from all sides. Thick cortical adhesions often prevent the free seepage of fluid; forceful injection leads to buildup of fluid that might either break the adhesion or rush the fluid through the posterior capsule.

Source: Priya Narang, MS, and Amar Agarwal, MS, FRCS, FRCOphth


Hydrodissection should preferably be performed through the main incision with intermittent release of pressure by indenting the corneal lip of the incision. Hydrodissection through a side-port incision should be discouraged as it can easily build up the pressure inside the eye. Dr. Yeoh suggests performing cortical cleavage dissection wherein the anterior capsule is slightly tented up before fluid injection begins followed by depression of the nucleus to break the cortical adhesions.

The surgeon should tread carefully while emulsifying the nucleus as these cases can suddenly encounter a nucleus drop. All the operating parameters for a phacoemulsification surgery should be lowered. If the anterior chamber deepens and nucleus tilt is observed, then phacoemulsification should be abandoned and the procedure completed with either manual small-incision cataract surgery or extracapsular cataract extraction. Posterior-assisted levitation may be needed if the nucleus lies in the anterior vitreous. In such a situation in which the nucleus is yet to be emulsified, the IOL scaffold technique can be helpful. Usually, the capsular rim remains intact as zonular dehiscence is not observed in these cases. A three-piece IOL can be easily placed on the capsular margin (Figure 2), and optic capture can be performed after performing limited anterior vitrectomy.
- Reference:
- Yeoh R. Br J Ophthalmol. 1996;doi:10.1136/bjo.80.5.486-a.
- For more information:
- Amar Agarwal, MS, FRCS, FRCOphth, director of Dr. Agarwal’s Eye Hospital and Eye Research Centre, is the author of several books, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery and Presbyopia: A Surgical Textbook. He can be reached at aehl19c@gmail.com; website: www.dragarwal.com.
- Priya Narang, MS, of Narang Eye Care & Laser Centre, Ahmedabad, India, can be reached at narangpriya19@gmail.com.