Glasses are vital for students and people to perform well in school in life. In the developed world glass wearing people are ubiquitous because it is such as common problem and one that is relatively easily remedied.
But in the developing world there is a much greater problem. A pair of glasses could cost 15 $ but due to the vagaries of the environment the wearer is faced with and the growth of a child over time, multiple glasses are needed over time.
What could cheapen these glasses and allow them to be expanded with the wearer’s head?
Prescription lenses have to be ground to a specific size for the wearer to be able to see. In addition to the manufacture of the lenses, someone has to determine the prescription needed by that person.
What if instead the child who needed glasses was determined to need glasses by a chart in every classroom. He was then given a dollar pair of glasses. He would look through the lens and peel off a layer of the plastic the lens was made of until his vision was clear and the letters on the poster was clearly visible.
The plastic peel off lens would allow the student to change the prescription, so as his eyes got worse he could peel off another layer on the affected eye until his vision was once again adjusted for.
The plastic peels are each shaped so that they focus the light back onto the foci of the due, just like regular glasses except they are plastic and easily made and easily adjusted without the necessary grinding.
As the wearer grows and his head get larger, the glasses would be able to elongate their arms using a simple slide mechanism. The lens would remain the same size throughout the life of the glasses while the arms and bridge would expand to account for the increasing dimensions of the wearer.
These glasses would be made entirely of plastic and would be cheap to make as well as useful for life of any wearer.
Sight is the most important sense. By allowing every one access to this sense everyone can live up to their true potential.