Student’s dynamo-powered otoscope delights doctors

In remote locations far from electricity and replacement batteries, a basic piece of medical exam equipment – the otoscope – can be useless.

The importance of an otoscope extends beyond the general examination of eyes, ears and throats. Among other uses, it can help doctors see the borders of skin lesions and find infants’ small, deep veins, which appear as dark lines.

“Electricity, if even available, is unreliable. I worry about where I’ll charge my batteries when I go to Ecuador,” said Vanderbilt nurse practitioner Ken Watford.

Senior biomedical engineering student Heather Stone picked a challenge from World Engineering Health to adapt a standard otoscope to use in remote, resource poor settings – her project for BME 290A (Service Learning and Leadership).

The order: It should operate by cranking, shaking, pulling or otherwise generating energy without batteries or access to electricity. Only energy storage and delivery apparatus should be adapted, not the optical sections. Plus, it must cost less than $100 in quantities of 10 or more. Stone’s solution: A small dynamometer to produce direct current. The otoscope would be a self-generating product that is charged by cranking a handle, similar to the power produced by a dynamo inside the body of a hand-cranked flashlight.

“I was interested in three projects listed by EWH, but I had to choose one,” said Stone, a diminutive whirlwind who can whip out a laptop from a backpack in short order to find photos of her work. “This project seemed to be one with the greatest potential impact.”

Professor Cynthia Paschal introduced the students to EWH. The organization uses the resources of university engineering programs to improve healthcare in developing nations. It began in 2001 with the vision of Dr. Robert Malkin and Dr. Mohammad Kiani, then professors in Memphis, Tenn.

“I haven’t met Dr. Malkin but I talked with him by phone many times, she said. Malkin is now at Duke University.

Stone’s initial aims were for the otoscope’s light to stay on with one minute of shaking or cranking, to seek the approval of 10 Vanderbilt Medical Center doctors, and keep the cost of production supplies low.

The result surpassed expectations. The total cost of the prototype is $4.50. The brightness needed for examinations lasts 1.26 seconds with 20 seconds of cranking. And, the otoscope stays on for 28 hours.

“I love it. Although it’s not quite a bright as I’m used to, it’s better than what I use in Ecuador,” Watford said. Eighteen VMC doctors approved the device; one found it lacking.

Otolaryngologists Steve Goudy and Bob Labadie say they can see all the structures they need to see and the light is adequate to diagnose common pathologies. Labadie suggested Stone patent the device.

The young engineer said, “I think I can make it smaller and more durable, and get a brighter light.”