Carl Zeiss Research Awards Presented for
New Eye Therapy and Blue Laser Diodes

JENA, GERMANY, Aug. 1 -- The winners of this year's Carl Zeiss Research Awards are Dr. Ursula Schmidt-Erfurth of the Luebeck University Hospital, Germany, and Dr. Shuji Nakamura of the University of California at Santa Barbara. The awards were presented at the recent annual meeting of the German Society of Applied Optics in Jena, Germany.

Dr. Schmidt-Erfurth was honored for her development of the basic principles of photodynamic therapy of the eye. This technique can be used to halt vision impairment caused by a condition known as wet, age-related macular degeneration -- the leading cause of blindness in people over 50 years of age. From 1990 to 1992, during her research at the Welman Laboratories for Photomedicine, Harvard Medical School, Dr. Schmidt-Erfurth developed the concept of using the photodynamic principle on the eye. This concept was based on her in-depth work on retinal disorders and on her examination and laser treatment of patients suffering from macular degeneration. The study on the photodynamic therapy of a neovascular retinal disorder, published in 1998 by an international work group organized by Dr. Schmidt-Erfurth, represented the first use of this method on the human eye.

Since then, considerable success has been achieved in introducing photodynamic therapy as a minimally invasive and highly selective technology in ophthalmology and in obtaining relevant results in treating macular degeneration. The basis of this therapy is a photochemical effect induced by laser irradiation.

Together with CIBA Vision, Carl Zeiss has helped photodynamic therapy to achieve a breakthrough. The VISULAS 690s medical laser from Carl Zeiss is designed to provide a suitable system configuration for efficient treatment while subjecting the patient to minimum discomfort.

Dr. Nakamura received the Carl Zeiss Research Award for developing high-brightness blue light-emitting and laser diodes, which enable such applications as full-color displays and indicators. The shorter wavelength of the laser allows a fourfold increase in resolution in CD players and CD-ROM drives, compared with traditional equipment using infrared lasers to read the signals.

Dr. Nakamura's successful development of the blue laser diode is based on new fabrication methods for gallium nitride -- a material often considered too difficult to handle. In 1994, Dr. Nakamura succeeded for the first time in producing a blue LED with a brightness of over 1 cd. He eventually achieved a brightness of 10 cd.

ZnSe-based laser diodes had long been considered to have the shortest wavelength of all laser diodes, but they emit green light and have a short lifetime. In 1995, Dr. Nakamura succeeded in fabricating a semiconductor laser diode with an emission wavelength in the 390-440 nm range. The following year, he increased the lifetime to 35 hours at room temperature. Nichia Chemical Industries Ltd. has begun marketing the blue laser diode, which has an output power of 5 mW and a lifetime of 10,000 hours.

The Carl Zeiss and Otto Schott Research Awards are presented every two years on an alternating basis to recognize outstanding work in the fields of optics and glass technology. Both awards are administered by the German Association for the Promotion of Science.

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