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Visx, Nidek see patent ruling differently
The sparring excimer laser manufacturers received a split decision in a U.S. District Court hearing. The judge found merit on both sides of the issue.
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SANTA CLARA, Calif. — Nidek and Visx both claimed victory in a U.S. District Court ruling on their ongoing patent battle. The judge in a special hearing here in the Northern District of California seemed to side with Visx on some issues and Nidek on others.
The lawsuit, brought to court by Visx against Nidek, centers on disagreement over the language of three phrases in patent No. 5,108,388 and one phrase in patent No. 5,735,843. Visx owns both patents. Visx claims that characteristics of Nidek’s EC-5000 excimer laser infringe on the patents.
The disputed phrases are 1) “volumetric removal,” 2) “the ablation overlaps the optically used area of the cornea,” and 3) “depth penetration into the stroma” all in the ’388 patent, and 4) “mask having an aperture” in the ’843 patent.
The court appeared to side with Visx’s interpretation of phrases 1 and part of 4 while siding with Nidek on phrases 2 and 3.
Another court fight
The ruling came from a “Markman hearing,” in which both sides in a dispute present their arguments to the court for interpretation of the patent claims at issue. The legal precedent of a Markman hearing can influence the outcome of a trial on issues of validity and infringement of patents.
The ’388 patent describes “a method for producing a surgical excision of controlled depth and shape in a cornea by ablative photochemical decomposition of corneal tissue without thermal damage to the corneal tissue.”
The disputed phrases lie in the following excerpts from the patent, which describes “generating a laser beam in the far ultraviolet region of the energy spectrum at a wavelength selected to produce ablative photochemical decomposition of corneal tissue without thermal damage to the corneal tissue” (emphases added):
- “directing said radiation in a controlled manner onto said corneal tissue to induce ablative photo- chemical decomposition thereof in a volumetric removal of said corneal tissue without thermal heating to create a surgical excision of controlled depth and shape with depth penetration into the stroma; and
- “wherein the ablation overlaps the optically used area of the cornea.”
On the first issue, volumetric removal, Nidek said that Visx had previously attempted to narrow the definition of “volumetric removal” during the course of prosecuting the ’388 patent in order to distinguish its invention from references found in prior art. Nidek said that in its current lawsuits with Visx regarding the patent, Visx is now trying to rebroaden the meaning by stating that the phrase covers the removal of material of any size or shape.
According to court documents, Nidek was concerned that instead of covering only one shape of incision, the Visx patent will now cover any shape of incision, for example a V-shaped incision.
The court found that the word “volumetric” merely modifies the term “removal,” describing incisions that leave behind precisely defined, non-jagged edges with a predetermined shape and depth. The patent does not further limit the shape of the remaining surface.
Defining overlap
Regarding the phrase “the ablation overlaps the optically used area of the cornea,” both Visx and Nidek agreed that the claim language has no special meaning and can be interpreted in layman’s terms. Visx’s proposed definition of over lap is essentially the same as the term “within.” Nidek claimed that be cause Visx’s patent uses the word “overlaps,” the laser ablations must always include a portion but not all of the optically active area and a portion but not all of the non-optically active area. Nidek contended that some of the patent’s art shows the ablation taking place inside the optical field only and not in the surrounding area, therefore not “overlapping.”
The court, however, constructed its own definition and found the term “overlap” in the ’388 patent to mean that the ablation must include a portion — and may include all – of the optically used area of the cornea and must also include a portion – and may include all – of the non-optically used area of the cornea as well. The court’s definition comports with Nidek’s definition because it must include a portion of the non-optically used area.
Layer above the stroma
With regard to “depth penetration into the stroma,” Visx contended that the plain language of the patent indicates that the invention must ablate stromal tissue to some depth but contains no limitations with respect to how the invention achieves the penetration or whether it requires the removal of layers above the stroma.
Nidek contended, however, and the court agreed, that the patent describes an ablation that must remove layers above the stroma. The court found that the patent suggests the apparatus must pierce through the outer layers of the cornea before removing stromal tissue. The judge remarked that if the device were meant to focus radiation directly on the stroma without first ablating the outer layers of the cornea there would be no need to distinguish between corneal tissue generally and the stroma specifically.
The court said the patent implies that the device penetrates through outer layers of the cornea in addition to the stroma when it describes the “bond breaking occurring in the epithelium and stromal collagen.”
Mask description
With regard to the final disputed phrase, the ’843 patent describes a “system comprising a mask having an aperture for providing a graded intensity to the cornea from center to edge with more intensity at the center than at the edge.”
Visx contended that the phrase “mask having an aperture” describes an opaque material having a transparent or translucent hole or opening, while Nidek contended that the mask must be on a plate having an opening or series of openings each with a fixed size, the plate being conformed to fit on or in close proximity to the eye.
The judge sided with Visx, stating that the term “mask” can be understood more broadly to include the variable slit, the aperture and the intervening lens. The judge also said that nowhere in the claim does it state that the aperture cannot be of variable size. Finally, the court found that Nidek’s claims, that the mask noted in the patent cannot accomplish the task of defining the area of the cornea subject to light, and that the specification only envisions one way of providing graded intensity to the cornea, are refuted by the specifications and claims of the patent.
Press release fallout
In a press release dated 2 days after the ruling, Visx noted that the judge determined the scope of certain patent claims asserted by Visx. As a result, the release said, Visx believes Nidek will be found to infringe its patents.
Liz Davila, chairman and chief executive officer of Visx, stated, “We believe this ruling provides Visx with the support needed for full injunctive and damages relief against Nidek. This is another step in the process toward trial, which we anticipate will commence in the fall of 2002.”
Three days later, the other side issued its own release stating that the ruling by the District Court represents a major victory for Nidek that will have considerable impact on the case as it proceeds toward trial.
According to Nidek, in the ruling the court “largely embraced Nidek’s position.” The judge found for Nidek on critical issues dealing with the ’388 and ’843 Trokel patents, the release said.
The ruling “is a clear win for Nidek,” the press release said. “Over Visx’s strenuous objection, the District Court in a well reasoned opinion agreed with Nidek that the ’388 patent requires laser ablation of not only stromal tissue but also the layers of the cornea above the stroma. As such, the FDA-approved indications for Nidek’s EC-5000, PRK and LASIK, do not infringe this patent.”
Hideo Ozawa, president of Nidek, responded to the ruling by stating, “We are very pleased with the Court’s interpretation of the scope of these patents. Nidek earnestly hopes that Visx will re-evaluate its position in the various litigations between the two companies. This finding reaffirms that Nidek’s technology employed in the EC-5000 is unique to Nidek alone.”
For Your Information:
- Visx can be reached at 3400 Central Expressway, Santa Clara, CA 95051; (408) 733-2020; fax: (408) 773-7373. Nidek can be reached at 47651 Westinghouse Dr., Fremont, CA 94539; (510) 353-7707; fax: (510) 226-5750.