The Global Focus microscope is sharpening the focus on tuberculosis

Imagine a two-and-a-half pound microscope that can be carried in a backpack, runs on batteries, and only costs $240.  A microbiology major’s dream?  Probably.  But it is also a reality, a winner of the Hershel M. Rich Invention award from the Rice University Engineering Alumni, and one of the most promising technological advances for diagnosing TB and other diseases in low-resource settings. 

Andrew Miller holding his microscope. Photo taken by Jeff Fitlow of Rice University News.


The Global Focus microscope was invented by Rice University alumnus Andrew Miller during his spring 2009 semester.1  He began his senior design project with the goal of developing a small portable microscope as part of a larger “diagnostic lab in a backpack” project.  He fashioned the plastic shell with a 3-D printer, used a top-mounted LED flashlight for illumination, and included a shelf on which the user could slide a cell phone to take pictures and e-mail them.1,2  It provides 1,000X magnification, can fit in a lunchbox, and its design is so simple that five screws attach the outer casing to the single-piece body.1  As soon as he presented the finished product, its potential was instantly recognized.  “This is hugely significant as a point-of-care tool clinicians can use for tuberculosis patients, whether they’re in Asia or Africa or even in West Texas,” said Edward Graviss, director of the Methodist Hospital Research Institute’s Molecular Tuberculosis Laboratory. “The first identification of TB is usually made with a smear, and it will be good to know that in the field instead of having to wait three or four days to get the smear to a lab.” 

Tuberculosis is one of the “big three” global infectious diseases, although HIV/AIDS and malaria typically receive more of the attention.  It is estimated that one third of the entire world’s population is infected with Mycobacterium tuberculosis, with 5-10% of infected individuals becoming ill or infectious at some point in their lifetime.3  The WHO estimates that 1.3 million people died from the disease in 2008.  Southeast Asia has the highest percentage of incident cases, though sub-Saharan Africa has the highest incidence rate and the highest mortality rate per capita.  Someone in the world is infected with the TB bacillus every second. 

The hope is that Miller’s invention will provide an inexpensive and effective tool that can be used for diagnosis in resource-poor settings that may not have electricity or even an operational clinic.  A study testing the microscope’s diagnostic capability was published in the open-access journal PLoS ONE at the beginning of this month.  Out of 63 smears of suspected TB cases from Tehran, Iran,4 similar findings between the Global Focus microscope and a reference-standard fluorescence microscope were reported in 98.4% of cases. 

Miller is now working for a San Francisco company that produces ventricular assist devices, though he is still working on the microscope part-time: he and Rice University have paired up with a medical device consultant to produce twenty microscopes for field testing next month.2,4  Also, a new team of Rice students is currently developing image processing software for smart phones to help untrained clinicians make accurate diagnoses.  “The project was about an opportunity to contribute to global health,” said Miller, acknowledging it helped him land a top job out of college. “It was a great motivator, what kept me in the lab so long.”1 

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