Refractive SurgeryRefractive Surgery

here are spatulas, flippers, cannulas, for-ceps, and instruments too unusuallyshaped to put into a category — all com-peting for the attention of the growing

number of ophthalmologists performinglaser in-situ keratomileusis (LASIK).

LASIK is booming and so is the number ofhandheld instruments designed to managethe corneal flap.

One LASIK surgeon can name five instru-ments he uses to manage flaps. Louis E.Probst, MD, of London, Ontario, Canada,said he seeks instruments that minimizeepithelial trauma. After the keratome cuts,Probst lifts the flap with a smooth LASIKForceps or a Machat Retreatment Spatula(both from ASICO) for retreatment cases.

“When using the ACS [Auto-matedCorneal Shaper] microkeratome, I protectthe flap with the Slade Flap Spatula (ASICO),which is angled to allow placement over thenasal hinge. When using the Hansatomewith the superior hinge, I protect the flapwith the Probst Hansatome Flap Spatula(Bausch & Lomb), which I designed to allowprotection of the superior flap while main-taining my hands in the superior position.”

Probst also designed an irrigating cannu-la to replace the flap. The ProbstHansatome LASIK Cannula (Bausch &Lomb) is bent to allow the surgeon tomaintain a 12 o’clock hand position. Probstis director of clinical care for TLC The LasCenter and is its London Office’s medicaldirector. He is also an assistant clinical pro-fessor at University of Western Ontario.

For Mastel Precision, Richard A. Erdey,MD, of CoIumbus, Ohio, designed a two-instrument retreatment set (not yet named)that is due for release this spring. The firstpiece is a 9-mm optical marker, which is

applied over the original keratectomy site. Itsimprint will allow the flap to be reliftedwhere it was originally cut, he explained.Other instruments permit the epithelium totear in sheets, extending the tear beyond theoriginal cut, he said. “This device allows theepithelium over the edge of the flap to bemore cleanly cut — like tearing a piece offolded paper, “Erdey said.

Another instrument due out this spring isthe Johnston LASIK Flap Applanator (RheinMedical).

“Everyone’s doing it differently and noth-ing's working well,” said Robert M. Johnston,MD, of Leesburg, Va., of dehydrating andrealigning the flap. He said 5% to 10% ofpatients develop visual problems due tomicro striae.

His device “applies pressure on the flap,emanating from a central point and distrib-uting it with diminishing force to the edges,”he said. “It largely eliminates lines of stress.”

Since using the applanator, a ring of metalwith a dear, convex bottom, “I can’t remem-ber the last time I had to reposition the flap,”said Johnston, a clinical instructor at HowardUniversity.

Ernest W. Kornmehl, MD, of Boston, hasdesigned flap instruments for Atorn, includ-ing the LASIK Sweep. It is longer than a can-nula, so its blunt side can reach the entire stro-mal bed, and its curvature matches thecornea, he explained. He uses it every 20 sec-onds during the procedure.

This LASIK Press is used postoperatively toremove excess fluid with its round, smoothhead. On rare occasions, he uses it the dayafter surgery to remove extra hydration,which could render a patient’s vision only20/50, for example. The patient usually willbe restored to 20/20 or 20/25 immediately,

said Kornmehl, medical director at Center forLaser Vision Correction and a professor at fiveuniversities.

ARUN C. GULANI, MD, of New York City, hasdesigned 10 LASIK flap instruments, each for a specif-ic purpose. He said the five-piece Gulani LASIKRevision Set (Bausch & Lomb) is “for revising andfine-tuning previous LASIK surgery without the re-use of the intimidating microkeratome and its inher-ent complications…” This set comprises the CornealIndentor, Flap Outliner, Periphery Dissector andInterface Spatula, and the Corneal Shovel designedto achieve “resistance-guided uniplanar dissection.”

He designed the Triple Function Gulani LASIKCannula (Eagle Labs) for simultaneous interfacecleansing, flap opposition, and squeegee. Gulani alsocreated the Gulani Edge Delineator and Liftor (Bausch& Lomb) for corneal flap lift at a slit-lamp; GulaniLASIK Globe Stabilizer and Flap Restrainer (ASICO),for use in nystagmoid apprehensive patients; GulaniLASIK Edge Marker for flap realignment (Bausch &Lomb); and Gulani Hyperopic Flap Liftor (Duckworth& Kent) for corneal flap lift with minimal erosion ofthe sculpted central stromal steepening.

Charles H. Williamson, MD, Baton Rouge,La., uses an irrigating cannula to replace aflap, with the ”curved blunt portion [usedlike a squeegee [to get] some extra fluid out.”Then he stretches the flap gently with aWexel sponge.

Williamson, an associate professor atLouisiana State University Medical School,also designed a retreatment spatula for use athis own surgical center. The instrument,made for him by Diamatrix has a point thatis used to break bonds in a can-opener style,not cut them. ■

New Flap instruments are created as LASIK goes mainstream

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VOLUME 4, NUMBER 4 APRIL 1999

Refractive SurgeryRefractive Surgery

Arun C. Gulani, MD,recently proposed twonew laser in-situ kera-tomileusis (LASIK) classification systems at the 1999 Contact LensAssociation ofOphthalmologists meeting in Las Vegas.

LASIK complications classificationGulani said that the potential complica-

tions related to LASIK require intensive pre-ventive efforts and close attention to detailin this micron-precision surgery. “It is impor-tant to shed our routine surgical complica-tion nomination and adapt to the present eraof micron thinking and analysis,” Gulanisaid. He proposes visualizing the LASIK tissue components as tiers:

• Corneal section: Corneal flap made bythe microkeratome

• Interface: Intervening space between thecorneal flap and stroma

• Stromal bed: The ablation bed of the corneaHe assigns LASiK complications to their

respective levels of affliction in the cornea(Figure 1). This three-tier classification gives acomprehensive, yet lucid, visualization ofLASIK corneal complications. “It can also beupdated periodically as we encounter newercomplications....” he said.

Excimer laser beam profile classification In another presentation at the CLAO

meeting, Gulani discussed the prevention ofexcimer laser malfunction during LASIK.

He said that the “excimer laser is a person-

ified extension of our own precision, at sub-micron tolerance.” Gulani emphasized theneed for physicians to monitor the invisiblelaser beam on a regular basis to achieve pre-dictable refractive surgery.

The excimer laser output is nonhomoge-nous at the source and requires a precisecombination of lenses, prisms, and mirrors toachieve the homogenous beam profile out-put, Gulani said. This is directly responsiblefor predictable homogenous refractive sculpt-ing, he said.

In order to address beam variations,Gulani classified beam-profile testing intodirect and indirect techniques. The directtechnique analyzes the beam profile andhomogeneity directly resulting from athree-dimensional top-hat pattern. Theindirect technique uses ablatable materialwith the laser to analyze, observe, andrecord beam profile.

There are numerous materials available forthis indirect testing, including Chiron plates,PMMA plates, Wrattin gelatin, CIBA ExACTBeam profile film, and others, Gulani said.

He has been using a different, morevisually informative technique of analyzingexcimer beam homogeneity and profileusing ExACT film. In this technique, hestops ablation after breaking through thefilm on the plate. The plate is then tilted atan angle and a fiber-optic light is projectedat an incident angle to the plate to reveal awave pattern from the excimer beam. Gulanihas termed this appearance the “excimer-beam profile topography,” since it is a directcorrelate of the laser ablation pattern on thepatient’s cornea.

He also has classified laser beam profiles tosimplify and standardize reporting and dis-cussion. This nomenclature, termed the“excimer-beam-profile classification” (Figure 2),will help the exchange of information in amore systematic manner with respect to thetype, position, size, and area, he said.

“Presently, we report laser-beam abnor-mality in a descriptive way only. Once weuse this classification, we can record beamprofiles and send accurate beam descriptionby telephones, fax, or e-mail to service per-sonnel across the world, as well as amongpeers on the same standardized level ofinformation exchange,” Gulani said. ■

Proposed classification systems for LASIK reporting