5 Questions With Michael C. Knorz, MD

1. What was the topic of your presentation as the winner of the 2008 Asia Pacific Association of Cataract and Refractive Surgeons Lim Lecture?
My lecture was about the advantages and wide range of applications for femtosecond laser surgery. Femtosecond lasers provide several advantages over mechanical microkeratomes, particularly the creation of smoother flap bed surfaces; more consistently thin, planar flaps; and customization of the sidecut design. I discussed the many applications—in addition to flap creation—that femtosecond lasers can be used for, including femtosecond keratoplasty and corneal transplantation; intrastromal refractive correction through tissue excision (eg, femtosecond lenticule extraction [FLEx]) and tissue ablation; and intralenticular and/or intracorneal approaches for presbyopia correction, lenticule extraction, or tissue ablation (FLEx, or IntraCor), either within the crystalline lens or the cornea. Additionally, femtosecond lasers can be used to create lenticules for refractive corrections and ablate tissue in the corneal stroma.

2. In what ways do you think IOL technology will evolve in future years?
We will see a significant increase in presbyopia-correcting IOLs in the next few years. More advanced accommodating and multifocal IOLs will also become available. Currently, multifocal lenses are the most effective presbyopia-correcting IOLs, as almost every patient will be able to read with a diffractive multifocal IOL, like the Restor (Alcon Laboratories, Inc., Fort Worth, Texas). The downside is that halos and other visual side effects occur with multifocal IOLs. Accommodating IOLs, such as the Crystalens HD (Bausch & Lomb, Rochester, New York), are less effective at near but provide good intermediate vision, with fewer visual side effects. Dual-optic designs, such as the Synchrony IOL (Visiogen, Irvine, California), also look promising. The perfect restoration of accommodation (eg, by refilling the capsular bag) has been tried for many years and may be successful in the future.

3. What is your approach to bioptics using IntraLase?
I use bioptics in two groups of patients. The first group is patients in whom I did not achieve the planned refraction. In these patients, I will perform an IntraLase (Advanced Medical Optics, Inc., Santa Ana, California) LASIK procedure approximately 2 to 3 months after implantation of a phakic IOL or after refractive lens exchange (RLE).

The second group is patients in whom I know that one procedure will not be enough to correct their refractive error. This group typically consists of patients with corneal astigmatism of more than 2.00 D. As I know I have to do a laser enhancement, I will cut the LASIK flap with the IntraLase femtosecond laser immediately prior to the lens procedure without lifting it. The beauty of the IntraLase flap is that it does not have to be lifted immediately, which means the cornea is undisturbed during phakic IOL implantation or RLE. I will then lift the flap and perform the excimer laser ablation approximately 3 to 4 weeks later, when the IOL has stabilized and the wound has healed.

4. What do you hope to accomplish in the next 5 years?
I hope to grow the market for refractive surgery by expanding the use of femtosecond LASIK in lower refractive errors and by replacing LASIK with phakic IOLs in higher myopes.

5. What is your favorite way to spend a day off?
I enjoy spending time with my family. In the summer, I go hiking or camping with my son, Peter, 12, and in the winter I go skiing with my daughter, Caroline, 10.