I have been working with the BD Microkeratome (BD Ophthalmic Systems, Franklin Lakes, NJ) for the past year in my refractive practice. My interest in the device related to its providing an automated microkeratome alternative, which allows surgeons to create a range of flap sizes and thicknesses. I easily learned to use the device and found it reliable.
DESIGN
The BD Microkeratome features two direct-current motors, one dedicated to blade oscillation (approximately 12,000 rpm) and the second used for head translation (approximately 4 mm per second). The “piston-drive” design of the translation mechanism has no exposed track or gears, thereby virtually eliminating the occurrence of an incomplete flap due to the microkeratome's jamming on the drape or lashes (Figure 1). Prior to creating the keratectomy, surgeons may use a set of applanators that come with the unit to confirm that the flap will have the appropriate diameter. The blade oscillation and translation speeds are not adjustable.
FLAP THICKNESS
Similarly to research by Hiroko Bissen-Miyajima, MD, of Tokyo, I have found that the BD Microkeratome creates flaps of reproducible and predictable thickness, both important qualities in our quest to avoid postoperative ectasia. Although I have used the 130-µm head extensively, I have experienced no increased incidence of micro- or macrostriae in eyes treated with it (generally, flaps thinner than 160 µm are more prone to developing striae owing to the lesser amount of tissue). The microkeratome also creates flaps with rings that are 160 and 180 µm thick with heads that permit the surgeon to create a flap that varies between 8.5 and 10.0 mm in diameter.
The Surgeon
Before introducing another microkeratome into my practice, I wanted to ensure that a steep learning curve (such as the one many of us experienced with microkeratomes 5 to 10 years ago) would not compromise surgical quality and patient safety. I felt reassured on this point because the BD Microkeratome is a one-piece unit, so no assembly on the eye is required.
This device creates a nasal hinge, and I have achieved my best results with a mild nasal displacement of approximately 1 mm, similar to my technique with the Automated Corneal Shaper (Bausch & Lomb Surgical, Inc., San Dimas, CA). I was able to confirm adequate suction with the aid of an audible alarm, the occurrence of mild mydriasis, and the patient's subjective report of his vision's becoming gray.
I found that the microkeratome's profile facilitated its placement upon the eye. Because it is a horizontal unit, neither prominent orbital rims nor limited interpalpebral space present a problem. Additionally, the ring size does not require excessive retraction of the patient's eyelids.
The Technician
Happily, my technician also enjoyed a short learning curve with the BD Microkeratome, which is easy to assemble. In addition, she did not face multiple readouts during the keratectomy, because a loss of suction results in the automatic stoppage of blade oscillation and an audible alert. The absence of gears and a track simplifies microkeratome maintenance and facilitates case turnover.
CONCLUSION
The BD Microkeratome has proven a reliable microkeratome, and I have discovered no drawbacks to its use to date. Easy handling, a short learning curve, and simple maintenance have smoothed its integration into my practice.
