July 28, 2010

Seahorses May Hold Key To New Sight

Seahorses are helping scientists gain new understanding about how detailed vision develops "“ in research which may open a way to restore sight in people with age-related blinding diseases.

Researchers at the Vision Centre have found that the seahorses' eyes share similarities with the human eye, leading to the possibility of imitating the development of the seahorse's fovea to regenerate this vital region of the eye in people with impaired vision.

"The fovea is the tiny pit at the back of the eye, which is the source of all our detailed vision. Without a functioning fovea, you are legally blind "“ that's how important it is," explains Dr Keely Bumsted O'Brien of The Vision Centre and Australian National University.

"Our idea for restoring sight is thus to restore the fovea by imitating the development process of this crucial region of the eye."

"However, mimicking this development in mammals has proved extremely difficult so far, but our exploration of how seahorses develop their fovea may provide us an alternative pathway that we can mimic and adapt to humans."

"We can show that the development of seahorses' vision shares certain similarities with that of humans," says Hie Rin Lee, a doctoral research student who is working on the seahorses.

"There is a high density of cones which provide color vision in bright light in the seahorse fovea, and no rods, the cells needed for vision in dim light. This structure is very similar to that of the human eye, and understanding how it develops in seahorses may help us understand more about how it develops in humans, and how to repair it if it is damaged," she says.

Hie Rin explains that they investigated the development of the seahorses' vision by measuring the young and adult seahorses' responses in detecting small prey. This also led to another similarity with the development of our vision.

"By tracking their development we've also found that younger seahorses have a less developed fovea than do adults. This also applies to humans, as our ability to see fine detail doesn't develop fully until we reach the age of four or five".

Dr Bumsted O'Brien says that the ability to see fine detail, such as reading the words on a page or recognizing a face all depend on the fovea, this small pit in the back of our eye less than half a millimeter across.

"A lot of eye diseases, especially those that affect the elderly, stem from degeneration of the foveal region. For example, macular degeneration affects one in every seven people over the age of 50."

The research group also found that seahorses in tropical waters have better vision than to those in darker waters and are exploring how environment affects the development of the seahorses' sight.

Dr Bumsted O'Brien says that the results her group are obtaining open up exciting new research options for their group, including how the environment influences the development of our sight.

The Vision Centre is funded by the Australian Research Council as the ARC Centre of Excellence in Vision Science.


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