Femtosecond lasers will enable ophthalmologists to use surgical techniques that were impossible with conventional cataract surgery. I, for example, recently began using what I call the phacofirst technique in which the first surgical instrument in the eye is the phaco handpiece (Figure 1). This technique uses no capsulotomy forceps or needle, no hydrodissection, and no prechopping or rotating of the nucleus. I simply perform an intracameral injection of Shugarcaine (4% unpreserved lidocaine diluted 1:3 with BSS Plus [Alcon Laboratories, Inc.], which produces a 1% lidocaine solution with a pH of 6.97). Then, I completely fill the anterior chamber with viscoelastic. Using the phacofragmentation tip, I open the main incision, check the capsulorhexis, core the center of the nucleus, and remove the segments.
The steps of the phacofirst technique, in order, are,
• perform an intracameral injection of Shugarcaine
• inject a dispersive viscoelastic such as Viscoat
(Alcon Laboratories, Inc.) to completely fill the anterior chamber and coat the endothelium
• enter the anterior chamber though the primary incision using the sharp edge of the phaco tip
• verify and/or complete the capsulorhexis with the phaco tip (Figure 2)
• core out the central cylinder of a cylindrical/chopping pattern
• remove the nuclear segments
• remove the cortex with a side-sweeping, high-vacuum technique using the bent silicone I/A handpiece but avoid pulling the cortex to the center
There are several potential advantages of the phacofirst technique, including the need for fewer instruments, faster surgical times, and a simpler procedure. Without hydrodissection, the anterior chamber can be completely rather than partially filled with a viscoelastic when ultrasonic energy is applied (hydrodissection typically washes out some viscoelastic). The technique may increase safety as well, because avoiding hydrodis-section may decrease the risk of extending any tears or damaging the posterior capsule. Anecdotally, the corneas are clearer, and as first described by Robert Cionni, MD, there are fewer anterior lens epithelial cells.
The technique for nuclear removal I currently use, the cylinder chop, fits well with the phacofirst technique. To begin chopping, I create a set of nested cylinders in the center of the nucleus (Figure 3). The outer diameter of the largest cylinder is 3.5 mm but can be set to the surgeon's preference. A simple crosschopping pattern is also programmed with its outer diameter currently set at 5 mm. Simply removing the central core seems to create enough fluid circulation to loosen the segments; in fact, I find that the harder nuclei detach from the capsule the easiest.
The phacofirst technique would be impossible without a femtosecond laser. It is just one example of changes made possible by new technology. I predict further technical and technological innovation to occur, as femtosecond lasers and phaco units become more synergistic.
Stephen G. Slade, MD, practices at Slade and Baker Vision in Houston. He is chief medical editor of Cataract & Refractive Surgery Today. He is a consultant to Alcon Laboratories, Inc., and Technolas Perfect Vision GmbH. Dr. Slade may be reached at (713) 626-5544; email@example.com.