MANCHESTER, Conn.— Ocuco, Inc. has filed a request with the U.S. Patent Office to re-examine Carl Zeiss Vision’s Patent 6,089,713, which claims the invention of back-surface free-form progressive lenses.

In its request, filed Sept. 10, Ocuco, a developer of optical retail and manufacturing software, questions the validity of Zeiss’ key claims and asks that the ’713 patent be cancelled. The patent was issued to Carl Zeiss Stiftung, the parent of Carl Zeiss Vision, in 2000.

“Similar to the request that we filed for a re-examination of Seiko Epson’s patent 6,019,470, which was granted by the U.S. Patent and Trademark Office last July, our new request raises substantial new questions of patentability regarding Zeiss’ patent on essentially the same subject matter,” said Robert Shanbaum, president of Ocuco Inc., Ocuco’s U.S. subsidiary. VMail reported the Patent and Trademark Office’s move on July 12.

In May, 2013 Ocuco asked the Patent and Trademark Office to re-examine Seiko Epson’s patent, which covers the invention of back-surface, free-form progressive lenses.

In response to Ocuco’s request for re-examination, a spokesperson for Carl Zeiss Vision said, “The validity of Carl Zeiss Vision’s U.S. Patent 6,089,713 has already been thoroughly tested during the Zeiss-Signet Armorlite litigation in which the court and multiple juries found the patent was valid and enforceable over numerous invalidity contentions.

“The initiation of a patent re-examination does not excuse infringement or inducement of infringement,” the Zeiss spokesperson noted. “The patent remains in force and enforceable except in the highly unlikely event that the Patent Office and the courts through the various re-examination and appeal processes reach a final conclusion that the ’713 patent is invalid.

“Zeiss will continue to vigorously defend any further challenge to the patent validity to protect its interests and those of our licensees.”

In 2012, Zeiss prevailed over rival lens manufacturer Signet Armorlite in a lengthy lawsuit concerning the ’713 patent.