From Lee Eye Clinic (DYK) and the Department of Ophthalmology (JHJ), Maryknoll Hospital, Busan, Korea.
Presented at the American Society of Cataract and Refractive Surgery Symposium on Cataract, IOL and Refractive Surgery, March 25–29, 2011, San Diego, California.
The authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to Dae Yune Kim, MD, PhD, Lee Eye Clinic, 1124-11, Yeonsan5-dong, Yeonje-gu, Busan 611-831, Korea. E-mail: email@example.com
Phacoemulsification of hard cataracts is often a challenge. The disassembly of a hard nucleus is difficult because the nucleus fibers are strong and densely packed. Higher ultrasound energy, higher vacuum, and strong forces for nuclear separation may be needed. However, these may lead to problems such as zonular tear, capsular rupture, endothelial trauma, and corneal burn.1 Due to advances in phacoemulsification machines and the introduction of many effective surgical techniques, phacoemulsification of hard cataracts is more widely performed than extracapsular cataract extraction. To perform phacoemulsification of hard cataracts, it is important to divide the nucleus into multiple small fragments. Vertical chopping is an efficient technique for dividing a moderately hard nucleus and is also useful when the pupil is small. However, in cases of hard cataract, it is not easy to divide the nucleus initially because the nucleus is too hard to impale deeply with a phaco tip. Vertical chopping of a denser lens requires a sharper tip, but a sharp vertical tip may damage the capsule during lens manipulation. We describe a modified vertical chop technique, which we named the drill-and-chop technique.
The same surgeon (DYK) performed all of the cataract surgery using local or topical anesthesia. Phacoemulsification was performed through a clear corneal incision with a side port. When the cataract was white with a hard nucleus, trypan blue staining was necessary to visualize the anterior capsule. Using the soft-shell technique, the anterior chamber was filled with an ophthalmic viscosurgical device. The capsulorhexis was started with a bent-tip needle and completed with forceps. After hydrodissection, the central lens nucleus was drilled vertically with a Kelman phaco tip in sculpting mode of the Infinity Vision System (Alcon Laboratories, Inc., Fort Worth, TX). The depth of drilling may be approximately half the thickness of the nucleus (Figs. 1 and 3A). The silicone sleeve was retracted, exposing more of the phaco tip to maximize a deeper purchase.
Figure 1. The central lens nucleus is drilled vertically with a Kelman phaco tip in sculpting mode. The depth of drilling may be approximately half the thickness of the nucleus.
Figure 3. (A) The central lens nucleus is drilled vertically. (B) The central nucleus is impaled horizontally with clockwise rotation of Kelman phaco tip using short bursts of phaco energy starting at the point of vertically drilled lens area. (C) Vertical chopping. (D) The lens is rotated and reimpaled, and the vertical chop is repeated.
Using short bursts of phaco energy, starting at the point of the vertically drilled lens area, the central nucleus was impaled horizontally by clockwise rotation of the Kelman phaco tip (Figs. 2 and 3B). The chopping instrument (Fukasaku snapper hook, K3-2392; Katena Products Inc., Denville, NJ) was then placed just in front or to the side of the buried phaco tip. Using the side-port incision as a fulcrum, the distal tip of the chopping instrument was then pressed downward into the nucleus, with the phaco tip providing a counteraction and its clockwise rotation providing a small degree of upward movement. As the cleavage plane was created, the chopper and phaco tip were spread apart laterally, propagating a complete division across the entire nucleus from one pole to the other, as well as down and through the posterior nuclear plate (Fig. 3C). The lens was then rotated and reimpaled, and the vertical chop repeated (Fig. 3D).
Figure 2. The central nucleus is impaled horizontally with clockwise rotation of the Kelman phaco tip using short bursts of phaco energy starting at the point of the vertically drilled lens area.
The settings used during phacoemulsification to drill a hole were vacuum 50 mm Hg, aspiration flow rate 24 cc/min, phaco power 90%, and bottle height 75 cm. The settings used to perform chopping were vacuum 330 mm Hg, aspiration flow rate 30 cc/min, phaco power 90%, and bottle height 90 cm. The more dense the lens, the greater the number of cleavage planes necessary.
After dividing the nucleus, the blunt chopper was used to rotate the blunt periphery downward and to lift the sharp apex safely upward because elevating the apex minimizes the chances of the posterior capsule being torn by a sharp edge. When leathery posterior strands kept nuclear fragments attached to each other, the nuclear fragments were engaged and stabilized by the vacuum of the phaco tip while the nuclear fragments were partially drawn anteriorly and the chopper was used to transect the strands.
After completion of phacoemulsification, the cortex was irrigated and aspirated and a posterior chamber intraocular lens was inserted into the capsular bag and positioned. The ophthalmic viscosurgical device was removed, and the corneal incision was sutured with 10-0 nylon.
The drill-and-chop technique has been successfully performed in 21 eyes of 19 patients with cataract harder than nuclear opalescence 5 on the Lens Opacities Classification System III scale or hard cataract with white cortex. No intraoperative complication such as posterior capsule rupture or zonulysis occurred during surgery, and no postoperative complication such as fibrin formation, severe endothelial cell loss, or endophthalmitis was observed in any patient at 6 months postoperatively.
Since the introduction of the traditional phaco chop technique, many variations have been described, including the phaco quick-chop technique (vertical chop) and the snap-and-split variation.2 Although the vertical chop technique is efficient and safe for moderately hard cataracts, it is difficult to deeply impale very hard cataracts and to hold the nucleus in place during the vertical movement of the vertical chopper. Thus, for very hard cataracts, many surgeons use a sharp vertical chopper such as a pointed quick-chop tip. Because hard cataracts usually have leathery posterior nuclear strands, a chopper can be used to snap across these strands and free the nuclear edge. In that case, a sharp chopper may have a risk of posterior capsule tear.3 Incomplete chopping may not divide a hard endonucleus but may separate the cortex from the endonucleus. A technique in which the cortex is first separated from the endonucleus, followed by the removal of the endonucleus, has been shown to be safe, but it may also require the chop technique to efficiently remove the hard endonucleus and to reduce the phaco time.4
Whereas the conventional vertical chop technique uses a straight phaco tip, which impales the nucleus vertically, our technique uses a Kelman tip with rotation, enabling us to hold the nucleus horizontally. Vertical impaling of the nucleus with the phaco tip by depressing the chopper downward while simultaneously lifting the nucleus upward may cause torque or dislodge the nucleus.5,6 By horizontally impaling the nucleus, however, the phaco tip can hold the nucleus firmly against the downward movement of the chopper.
This technique is somewhat similar to the stop-and-chop, central debulking, and crater-and-chop techniques in that all are chopping techniques in which the depth of the nucleus can be known and the endonucleus can be impaled after initially grooving and dividing the nucleus. The crater-and-chop technique also allows safe endocapsular phacoemulsification.7 A limitation of the drill-and-chop technique is that it requires the Kelman tip in all cases.
To our knowledge, this technique has not been previously described in the literature. We believe that our stepwise approach to the vertical chopping technique enables the nucleus to be firmly held. This may be especially useful in patients with very hard cataracts and may be an ideal starting point for surgeons who are beginning to learn vertical chopping or wish to perform this technique safely.
- Pangputhipong P. Phaco technique for rock hard cataract. In: Buratto L, ed. Phacoemulsification; Principles and Techniques. Thorofare, NJ: SLACK Incorporated; 2003:549–550.
- Nichamin L. Phaco quick chop. In: Buratto L, ed. Phacoemulsification; Principles and Techniques. Thorofare, NJ: SLACK Incorporated; 2003:321–323.
- Steinert R. Phaco chop. In: Steinert RF, ed. Cataract Surgery: Techniques, Complications, and Management, 2nd ed. Philadelphia: Saunders; 2004:183–191.
- Kim HK. Decrease and conquer: phacoemulsification technique for hard nucleus cataracts. J Cataract Refract Surg. 2009;35:1665–1670. doi:10.1016/j.jcrs.2009.05.038 [CrossRef]
- Chang DF. Phaco chop: pearls and pitfalls. In: Chang DF, Olson RJ, Seibel BS. eds. Learning Phaco Chop: Pearls & Pitfalls. Fairfax, VA: American Society of Cataract and Refractive Surgery.
- Chang DF. Making the case for phaco chop. Rev Ophthalmol. 2003;10:47–50.
- Vanathi M, Vajpayee RB, Tandon R, Titiyal JS, Gupta V. Crater-and-chop technique for phacoemulsification of hard cataracts. J Cararact Refractive Surg. 2001;27:659–661. doi:10.1016/S0886-3350(00)00702-1 [CrossRef]