Image via Wikipedia
[Author’s aside: What to write about? Oh, I never have that problem. And, right now, with all the annual meetings, new fiscal years, finished projects, and my holidays, I have a million things (ok, maybe only 842,123 of them) I want to share- but lack the time. So, I may seem to jump from subject to subject more than usual now, trying to at least touch on some hot items….Please abide me- I probably have terminal ADD, anyway!]
We all clamor for smartphones- the newer the better. Of course, with the new fees the providers are adding on, there may be some subsidence in demand, but I doubt it. Even in developing countries, smartphones are the rage. Afghanistan are paying their protectors (soldiers/police) via smartphones, so they don’t have to leave post to get funds to their families. And, now, a group at MIT (two are on loan from Instituto de Informatica) have developed clip-on eyepiece to perform eye exams.
“So, what?”, you ask? Well, there are 2 billion people with eyesight problems- at least 1/2 billion of them with no access to eye exams. With this clip-on device ($2) and a smartphone ($300-500), almost any adult can have his eyesight analyzed and be on the way to better vision. It tests for nearsightedness, farsightedness, and astigmatism! (Smartphones now have cameras with sufficient resolution- on the order of 1/2 the width of human hair, or about the same resolution that the optometrist is using in his/her office.)
You are all familiar with the Snellen eye chart. It’s a relatively easy test. It is subjective (the patient response is critical), but one also needs lens kits ($ 600-1400) and a “theater” (a place where the chart, lenses, and patient can be in a controlled environment). Enter NETRA, championed by Dr. Ramesh Raskar et. al. of the MIT Media Labs. (The results were presented at Siggraph 2010.) One looks through the eye piece and arranges red and green circles together. The number of clicks you need to align the dots provides your refractive index.
Compared to the Snellen method, the NETRA is:
- subjective (same)
- fast (much faster)
- resolution of <0.5 D (0.25 D for Snellen)
- requires no training (enough said)
- total cost of $ 302 (vs. $1000 or more) for the apparati
You can read the paper here:
Cerebrations: Roy A. Ackerman 
