Scientists image tiny light-sensing cells in eye

June 9th, 2011 - 7:08 pm ICT by IANS  

Washington, June 9 (IANS) Scientists have for the very first time imaged in astounding detail tiny light-sensing cells, known as rods, in the living eye. This breakthrough will help doctors diagnose degenerative eye disorders speedily, leading to quicker intervention and more effective treatment.

These tiny light sensing cells or rods in the eye allow us to see even in very dim light, being a 100 times more sensitive to a single light atom (photon) than the eye’s cone cells. Conversely, cone cells require tens to hundreds of photons to become activated.

Using adaptive optics with which astronomers study distant stars and galaxies, scientists can see through the murky distortion of the outer eye, revealing the eye’s cellular structure in unprecedented detail, reports the journal Biomedical Optics Express.

“The ability to see the cells you are trying to rescue represents a critical first step in the process of restoring sight,” said Alfredo Dubra of the University of Rochester, New York, who led the team from Rochester, Marquette University, and the Medical College of Wisconsin (MCW).

“One of the major hurdles in detecting retinal disease is that by the time it can be perceived by the patient or detected with clinical tools, significant cellular damage has often already occurred,” added team member Joseph Carroll of MCW, according to a Rochester statement.

The breakthrough is an improved design of a non-invasive adaptive optics imaging system. Dubra and his colleagues were able to push the device’s resolution to its optical limits of nearly 2 microns (a micron is 1/1,000 of a millimetre), or the diameter of a single rod in the human eye.

With the optical design method successfully demonstrated by Dubra’s team, even the smallest cone cells at the centre of the retina, known as the foveal centre, can be seen very clearly.

“Imaging contiguous rod mosaics will allow us to study the impact of a whole new class of blinding disorders on the retina,” said Steve Burns, professor in the School of Optometry at Indiana University, not involved in research.

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