Rated highly

Quality flap construction made easy with microkeratome

Becton Dickinson K-4000 microkeratome is simple to assemble and operate to create consistent flaps with excellent visual outcomes

with Robert M. Kershner, MD, FACS

—The K-4000 (Becton-Dickinson Ophthalmic Systems, Waltham, MA) is a highly user-friendly, versatile microkeratome that can reliably to create high-quality flaps of predictable dimensions, said Robert M. Kershner, MD, at the American Society of Cataract and Refractive Surgery annual meeting.

“The key to successful LASIK is proper flap construction, and there are a lot of microkeratomes to select from on the market. However, the BD K-4000 was designed from the ground up as an instrument for LASIK, and it really seems to give us what we need in flap creation and visual outcomes,” said Dr. Kershner, who is a private practitioner in Tucson, AZ, and clinical professor of ophthalmology, Moran Eye Center, University of Utah Health Sciences Center.

“In our clinical experience, the BD K-4000 has been superior to other microkeratomes in its ease of assembly and operation, and it creates flaps of consistent quality and thickness, making it particularly useful when operating on eyes where flap thickness is critical,” he said.

Testing in lab, patient eyes

Dr. Kershner reported in testing 100 laboratory eyes and 47 patients, no cases of irregular flaps or aborted flaps were encountered, and subjective assessments documented the excellent quality of the flaps and beds. Using a scale of 1 to 5, where 5 is excellent, mean scores for flap quality, flap edge quality, and bed quality were all 4.7 or 4.8, he said.

Flap thickness were measured using in all three available heads—130, 160, and 180 µm. Mean values obtained were 130.2, 160.7, and 181.4 µm, respectively, with standard deviations ranging from 21 to 24 µm.

“With its dual, independent motors and very tight tolerances in its track and rail system, the BD K-4000 consistently creates flaps of excellent quality with thickness very close to the labeled values,” Dr. Kershner said.

The quality of the flaps created with the BD K-4000 were confirmed in the analysis of refractive and visual outcomes in the clinical series. Preoperatively, mean sphere and cylinder values for the 47 eyes in the study were –5.75 D and +1.20 D, respectively; corresponding postoperative values were –0.25 D and +0.13D. Mean best-corrected visual acuity (BCVA) was 20/20 preoperatively and mean uncorrected visual acuity (UCVA) postoperatively was 20/18.

Reviewing other features of the BD K-4000, Dr. Kershner noted that both manual and automated handpieces are available. The keratome is simple to use with a one-handed technique, forward excursion of the head is activated with a single step on the remote control pedal and the reverse excursion is automatic. There is no on-eye assembly required.

The BD K-4000 also was carefully designed for safety. It has five ring diameters available, ranging in size between 8 and 10 mm. Surgeons will find that excellent suction is possible even when using the BD K-4000 on very flat or very steep corneas, in deep set orbits and tight eyelids.

Visibility is superior during the flap creation process. The keratome has no exposed gears or wheels that can jam or get caught on eyelashes or eyelids. Because the blade oscillation motor does not cut in the reverse pass, there is no chatter or bed disruption after the flap is cut. The oscillation rate, translation speed, and vacuum are continually monitored with on-board integrated circuitry, and the system shuts down automatically upon detection of problems that would interfere with acceptable flap creation.

Dr. Kershner noted that his surgical assistants have been pleased with the BD K-4000’s easy assembly, which is done completely off the eye in a few steps using a special inserter to install the blade. The automatic preoperative “flight testing” of the BD K-4000, which occurs with the touch of a console button, is also a welcome feature.

“We use a number of other keratomes at our center and the staff has complained about assembly and cleaning with each of those devices. They universally prefer the setup and disassembly of the BD K-4000. My fellows all prefer this keratome over the alternatives, as well” Dr. Kershner said

The BD K-4000 microkeratome. (Photo courtesy of Becton-Dickinson Ophthalmic Systems-Waltham, MA)

Robert M. Kershner, MD, Eye Laser Center, 1925 West Orange Grove Road, Tucson, Arizona 85704-1152 Phone: 520/797-2020   Fax: 520/797-2235   E-mail: Kershner@EyeLaserCenter.com

Dr. Kershner has no financial interest in the instrument or its manufacturer.

Take-home message

Ease of assembly and use make the BD K-4000 microkeratome the unit of choice for Robert M. Kershner, MD, FACS and his staff. Using a scale of 1 to 5, where 5 is excellent, mean scores for flap quality, flap edge quality, and bed quality were all 4.7 or 4.8, he noted.