In collaboration with Bérangère Granger, an optometrist with French optics company Essilor International, the world’s largest manufacturer of corrective lenses and the creator of the first progressive lens, Alvarez invented a device that measures how quickly people optimize their vision at various distances. The pair’s research shows the correlation between two visual systems – the ability to adapt to near or far distances and the speed with which a person’s eyes coordinate and converge to see a single image – to the capacity to adjust to progressive lenses.
“Progressive lenses require a sizeable investment of money and time and it is helpful to both the patient and the clinician to know who will be able to adapt to them,” notes Alvarez, director of NJIT’s Vision and Neural Engineering Laboratory. “For some people, objects appear larger than they actually are, which can be a problem on stairs and curbs. For others, periphery vision may blur when they turn their head from side to side.”
Progressive lenses, eye glasses that contain multiple lenses to correct vision at various distances within a single glass frame, are particularly useful for people with presbyopia, a decline in visual range. Part of the natural aging process, presbyopia is caused by the hardening of the lens and the weakening of the muscles that contract it. Symptoms, such as needing to hold a book or menu at arms’ length, typically become noticeable in the early to mid-40s.
Alvarez and Granger developed their device, which has been patented so far in the U.S., the European Union and New Zealand, as well as in several countries in Asia and Africa, over nearly a decade. The project started with a basic science question: what differentiates people who adjust to progressive lenses within a few minutes at the doctor’s office from those who struggle for weeks and eventually give up on them?
A key aspect of their device is the use of prisms to measure a person’s ability to adapt to a range of visual distances within a short period of time. In taking the test, patients look through a prism and report when they can see the object on the other side – typically letters, as in a conventional eye exam – as a clear, single image. Then a different prism is quickly placed over their eyes that makes the objects appear farther away and their ability to focus clearly is again measured. The prisms are alternated as many as 35 times within the space of a minute, allowing the clinician to determine how nimbly the person’s eyesight adjusts.
Currently, clinicians caution patients learning to wear progressive lenses that it may take a few weeks to adapt. With this in mind, Alvarez and Granger look forward to collaborating again to develop a method that would help people adjust to them more quickly, while expanding the population that can use them.
“The next step for our research will be to develop training that will help people adapt to progressive lenses,” Alvarez notes.
Alvarez and Granger will receive their award at the 2015 Edison Patent Awards Ceremony, to be held this November at the Liberty Science Center. The presentation will include videos of each of the winners, filmed this summer at the Edison Labs national historic site in West Orange.
Somenath Mitra, distinguished professor of chemistry and environmental science, and Zafar Iqbal, a research professor of chemistry and environmental science, won an Edison Patent Award last year for their technique for preparing carbon nanotubes for use in a variety of practical applications, from water purification to fuel cells.