Throwing light on the retina
“There have been several previous attempts to find better contrast agents, but they met with little success," says Professor Heinz Langhals of the Department of Chemistry at LMU. In collaboration with Professor Anselm Kampik and Professor Christos Haritoglou of the Ophthalmic Clinic at LMU Munich University Hospital, he has now been able to develop new optical contrast agents, which have the potential to broaden the therapeutic applicability of microsurgical techniques in eye surgery.
In the new study the researchers first chose a type of fluorescent dye – a so-called chromophore – with a particular kind of structure, and chemically modified it to make its fluorescent properties compatible with the optical sensitivity of the eye and the lighting conditions used during eye operations. They then coupled the modified chromophore to a molecule that specifically binds to the target tissue. "The new optical contrast agent not only allows one to visualize the target tissue with very good contrast, the high fluorescence yield means that it can be used successfully at high dilution," explains Langhals.
Unlike older optical contrast agents such as indocyanine green (ICG), which has been reported to be toxic, the newly developed dyes have no untoward effects on patients. Moreover, they are degraded relatively rapidly following the operation, so that vision is not compromised for so long during the post-operative phase. The new compound will soon be ready for routine use in patients, and promises to open up new opportunities for eye surgery, which should in turn lead to effective treatments for otherwise intractable diseases of the retina.
"Cyanine dyes as optical contrast agents for ophthalmological surgery"
H. Langhals, A. Varja, P. Laubichler, M. Kernt, K. Eibl, C. Haritoglou, J.
Med. Chem. 2011
Professor Dr. Heinz Langhals
Department of Chemistry
Phone: 089 2180 77699