Phakonit—lens removal through a 0.9 mm incision

Abstract

We congratulate Tsuneoka and coauthors1 for their interesting article about ultrasound cataract surgery with a 1.4 mm incision. The authors used a 20-gauge sleeveless ultrasound (US) tip that was inserted into a 1.4 mm incision in a post-mortem porcine eye. The infusion was provided through a side port, and nuclear emulsification was performed with the US tip occluded. A hooked infusion cannula with 3 apertures was used to stabilize the anterior chamber depth. The lens nucleus was emulsified and aspirated using the bimanual nucleofractis technique. To determine the incisional corneal burn, the authors measured the temperature at the incision site. No corneal burns were noted at the incision site after use of the sleeveless US tip. A hooked infusion cannula successfully stabilized the anterior chamber. In addition to experimental use in porcine eyes, the authors used the technique in 583 human eyes (from October 1999 onward) without corneal thermal burns or postoperative complications. Although their study focused on the porcine eyes, it would be interesting to know about the authors' experience in the human eyes; eg, the intraocular lens (IOL) type/model implanted via an ultrasmall incision of 1.4 mm, the postoperative follow-up, and visual results. Simultaneously with and independently from Tsuneoka and coauthors, we evaluated a new technique of bimanual phacoemulsification through a sub-1.0 mm incision using a sleeveless US tip and irrigating chopper. We termed it the phakonit technique, as phacoemulsification (phako) is performed with a needle opening (N) via an incision (I) and with an ultrasound tip (T).2 The technique is described in this issue (pages 1549–1552). We performed the phakonit technique for the first time in human eyes in August 1998. Live surgery was performed at the Phaco and Refractive Surgery Conference, Pune, India, in August 1998 and at the Symposium on Cataract, IOL and Refractive Surgery in Seattle, Washington, USA, in April 1999. Since August of 1998, we have performed the phakonit procedure in 305 eyes with varying cataract density (soft, semisoft, medium hard, hard cataracts). A best corrected visual acuity of 20/40 or better was achieved in 266 eyes (87.2%) after a minimal follow-up of 3 months. Although posterior capsule rupture (n = 5, 1.6%) and mild corneal edema (without incision burn) (n = 18, 5.9%) were seen in a few patients, none of the eyes in our study had incision burns, possibly due to the use of the pulse mode and continuous irrigation with chilled balanced salt solution (BSS®). Tsuneoka and coauthors also did not notice thermal burns after using the sleeveless US tip. In brief, the data of Tsuneoka and coauthors and our study suggest that with existing phaco technology, it is possible to perform phacoemulsification through ultrasmall incisions without significant complications. The unavailability of foldable IOLs suitable for implantation through ultrasmall incisions is probably the major limiting factor in their widespread use. It may become one of the preferred techniques for cataract surgeons in the future with the availability of mini-sized foldable IOLs that can be inserted through a 0.9 mm incision. Amar Agarwal MD Sunita Agarwal MD Athiya Agarwal MD Anand Bagmar MD Nishant Patel MD Suresh K. Pandey MD Sanjeev P. Shah aChennai, India bCharleston, South Carolina, USA