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Last Updated: Friday, 5 October 2007, 12:32 GMT 13:32 UK
Wi-fi update helps eye doctors
By Cristina Jimenez

Eye care clinic
Doctors can assess patients over the wi-fi connection
Thousands of residents of remote villages in southern India have easy access to eye care thanks to a specially designed, low-cost and long-distance wi-fi network.

The network allows specialists at Aravind Eye Hospital at Theni, in the state of Tamil Nadu, to interview and examine patients in nine remote clinics via high-quality video conference.

The new technology has been developed by researchers at the University of California, Berkeley and at Intel Corporation in collaboration with the Indian hospital.

One of the scientists' first priorities was to develop inexpensive and robust wireless networking technology which would stand up to the demands of developing regions.

The team could have used Wimax technology for long-range wireless networking but it is expensive to implement, explained Eric Brewer, a Berkeley professor of computer science and director of the Intel Research Berkeley lab.

Instead the Berkeley scientists adapted existing wi-fi technology. The key challenge is that wi-fi is designed for short, and not long distance communication.

'Better antennas'

"It turns out that you can get the radio signal to go further just using better antennas," says Professor Brewer. "However, in doing so, you have to pick a particular direction for the signal. This long-distance wi-fi is a fixed point to point wireless technology, like microwave links.

This could revolutionise the delivery of health care services and greatly improve the quality life in the rural developing world
Professor Eric Brewer, Berkeley
Berkeley's team has built wireless fixed links between the vision centres and the hospital. "Ours is a solution tuned to the needs of developing areas; NGOs (Non-Governmental Organisations) don't have the resources to implement the more expensive long-distance systems such as Wimax, " says Sonesh Surena, one of Brewer's PhD students working in the project.

The innovation for the India wi-fi system was to provide high bandwidth, for high quality video imaging, over long distances.

The researchers redesigned the software, so that some of the unneeded information typically sent over a wi-fi connection was discarded.

By combining their modified software with directional antennas and routers to send, receive and relay signals, the research team so far has been able to obtain network speeds of up to six megabits per second (Mpbs) at distances up to 40 miles.

Impressive results

But the team has obtained even more impressive results: "In our current world record, we achieved almost 6 megabits/second over a distance of 384 kilometres using only one link," he adds. These tests were carried out in a project in Venezuela last summer.

Vision centres in the region are now conducting real-time eye exams with doctors in Theni, over a direct connection 150 times as fast as the old dial-up modem, which used to cost $200 a year.

The long-distance wireless link, installed at a cost of $1,800, is practically free to operate.

"With our old system we only had audio, and a little of video," says Dr Namperumalsamy, chairman of Aravind Eye Care System.

He adds: "After the scientists from Berkeley came over, we have a powerful bandwidth and we can have video conferences, we can send e-mails and documents.

"Ultimately we can reach more patients at a affordable cost so that we can serve more people."

For P Ramaswamy, an 64 year-old patient, the vision centre that was built half a kilometre away from his home has made a great difference in his life.

He now can avoid a day's travel and have his eye test done locally.

'Skillful work'

"Someone told me that you can talk to the doctor in Theni through the system and that it is very convenient. I prefer coming here," he says.

Eye test
Patients can take eye tests at local clinics

At the moment, there are nine centres linked to the hospitals at Theni, which serve more than 50,000 residents in the area. And roughly 2,500 patients per month are using the video conference to meet with a doctor.

Each vision centre is run by three paramedical technicians, so that "eye doctors can do skilful work in the hospital such as surgery", says Dr Namperumalsamy.

The current network is expected to expand in the state to include five hospitals within the Aravind Eye System Care that will be linked to 50 clinics.

They are expected to serve half a million patients each year in rural South India - most of whom have no access to eye care today.

These vision centres will positively impact the health of the Indian economy, according to a recent study by the Aravind Eye Care System. It showed that 85% of the men and 58% of the women who had lost their jobs due to sight impairment were reintegrated into the workforce following treatment.

For now, the focus is on India, but the experimental wireless networking infrastructure developed by Intel and UC Berkeley researchers could make it possible to deliver eye care services in other rural areas in the developing world.

"Wherever there's a demand for eye care or other medical services, you can easily and inexpensively install one of our networks," says Professor Brewer. "This could revolutionise the delivery of health care services and greatly improve the quality life in the rural developing world."

The map shows the nine vision centres and the distance of each the wi-fi travels from Theni hospital
The map shows the nine vision centres and the central Theni hospital with the distance the wi-fi network covers

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