Medicine: A Sharper Image

An estimated 150,000 people in the U.S. who are not truly blind have to be treated as if they were, because they have so little useful vision that ordinary spectacles yield them only a faint, blurred image. This week, Columbia University’s inventive optometrist, Dr. William Feinbloom, announced that he had found a way to restore workaday vision to about half these patients so that they can read newspapers, watch TV or even do precision work in factories.

Conventional spectacles, Dr. Feinbloom explained, are simply magnifying glasses with lenses shaped like part of a sphere. No matter how much they magnify, they do not have enough “resolving power” to project a sharp image on the retina (the screen at the back of the eyeball) if the retina is damaged. Most partially sighted patients have retinas like a coarse-grained photographic plate: they can record a sharp image only if they are fitted with a lens of unusually high resolving power.

To achieve this, Dr. Feinbloom applied the principle of the microscope and made doublet lenses—really two lenses in a plastic rim, with a sealed air space in between. He also flattened the outer curves of the lenses from spherical to paraboloid shapes. The doublet lenses focus at infinity and the eye itself makes the focusing adjustment for objects beyond a few feet away. A short-focus pair is used for reading.

To show what the doublet glasses can do, Dr. Feinbloom told of a twelve-year-old Ohio girl who was born with part of the retina missing. Her sight was so poor that she could not go to regular schools and was learning Braille. With doublet glasses she breezed through elementary school. She got through high school with honors and now, at 17, is in college taking journalism and working part time as a reporter.