Reply: Hydrorupture of the posterior capsule in femtosecond-laser cataract surgery
We agree with Dr. Yeoh that older patients with larger denser nuclei are at increased risk for CBS. He has reported sudden pupillary constriction (“pupil snap”) during hydrodissection as a sign of hydrorupture of the posterior lens capsule.1 We reviewed the video recordings of the cases we reported and observed constriction of the pupil in both cases. The horizontal pupil diameter constricted by a maximum of 20%, and while this is less than the 30% constriction reported by Yeoh, the finding does support the clinical observation that abrupt pupil constriction during hydrodissection should alert the surgeon to the possibility of hydrorupture of the posterior capsule.
In addition to the maneuvers we described to reduce the risk for intraoperative CBS, Dr. Yeoh suggests balloting or pressing down gently on the nucleus to push gas or liquefied material around the nucleus before hydrodissecting. We suggest caution with this approach and recommend instead using a prechopper or blunt-tipped side-port instrument with the phaco tip to split the laser-cut nuclear segments to allow the gas to come forward. This technique avoids unnecessary posterior pressure on the lens capsule and zonules by balloting or pressing on the nucleus and also allows the gas to “pneumo-dissect” and frees up the nuclear segments. The laser-cut capsulotomy and nuclear fragmentation, presence of intracapsular gas, and laser-induced changes in the cortex are unique to femtosecond-laser cataract surgery; as a result, our surgical technique has evolved with experience of over 1000 femtosecond-laser cataract surgery cases performed in our unit. The unique benefit of pneumo-dissection in freeing the nuclear segments and the potential for hydrodissection to increase the risk for CBS have resulted in some surgeons eliminating hydrodissection and developing new techniques to safely and efficiently remove the nuclear segments following laser fragmentation.
© 2012 by Lippincott Williams & Wilkins, Inc.
1. Yeoh R. The ‘pupil snap’ sign of posterior capsule rupture with hydrodissection in phacoemulsification. [letter]. Br J Ophthalmol. 80. 1996. 486. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC505505/pdf/brjopthal00005-0106b.pdf2
. Accessed January 24, 2012.