The next time you are in a crowd of people, look around at how many of them are wearing glasses. Consider that some also have contact lenses or have had refractive eye surgery. Now dig out some issues of National Geographic and look at a story on Sub-Saharan Africa. How many of them are wearing glasses? Ever wonder why?

In the UK, there is an optometrist for every 8,000 residents. In Sub-Saharan Africa, the ratio balloons to 1 for every 1 million residents. For these people, the cost of a pair of glasses can cost months of income. Poor eyesight is more than a health and safety problem; it affects education, income, and quality of life.

Josh Silver, a retired physicist from Oxford, turned his humanitarian eye to this problem. He developed a pair of glasses that can be adjusted by the wearer to their needs. There is a single lens in front, a strong flexible piece of plastic behind, and a clear fluid in between. The amount of fluid can be adjusted by a screw syringe mounted to the eyeglasses frame. Mouse over Professor Silver's picture to see his invention.

Several web sites are associated with Professor Silver's work. The Centre for Vision in the Developing World at Oxford researches issues and solutions. Adlens is the technology company developing this product. Adaptive Eyewear is the not-for-profit company that distributes the glasses around the world. They have partnered with organizations to distribute 30,000 pairs of glasses. They hope to reach 1 billion by the year 2020.

When I go to the eye doctor, I sit behind a phoropter and the ophthalmologist tries different combinations of lenses to determine my eyeglass prescription which is then sent to a lab to grind lenses to my specifications. The beauty of Professor Silver's solution is to have a single set of glasses that can be fitted to any user's needs.

The glasses will not fix astigmatism and the shortage of eye doctors means that some eye diseases will go undiagnosed, but this is a solution for the many people who have basic refractive eye problems. Imagine the joy of a tailor who can continue his livelihood again, or an older person seeing their grandchildren in focus for the first time.

A colleague of mine, when I shared this story with her, called it a "day brightener". True, in so many ways.