Frequently Asked Questions

Q1. What is FoFo?

FoFo is a simple refractive error screening device that tells if you need glasses or not.

Q2. How to use the device?

Please refer to the instructions here.

Q3. What's the price of FoFos and where can I buy them?

FoFos are available in two forms:

a. As a set of 3 FoFos, each set costing Rs. 1180 (17 USD) including taxes. Inside the box set, you will find 3 assembled devices and 3 targets.
  Indian residents can purchase these sets from (free shipping). For shipping outside of India, please fill the form here. Our team will get back to you with the pro forma invoice and payment details. Please note that in this case, shipping charges are extra and payable before the devices are shipped.

b. As single FoFos inside flat envelopes, each costing Rs. 500 (7 USD) including taxes. Here, the device (along with its target) comes ready-to-assemble. It can be quickly put together with the help of the instruction pamphlet included in the envelope.
  Single devices are available for in-person purchase at the LVPEI KAR campus in Hyderabad, Indi However, bulk orders would be considered for shipment on a case-by-case basis. For inquiries, please write to us at

Q4. Where does my purchase go?

Your every purchase is a donation that will support the work of LVPEI in giving the gift of sight. LVPEI is committed to spending 80% of the revenue from FoFo on conducting comprehensive vision screening programs at rural schools. This means each FoFo you buy, pays for screening an entire classroom of about 30 students!

Q5. Can I buy glasses based on FoFo's readings?

No. FoFo has been designed as a preliminary screening tool rather than a diagnostic device. FoFo gives approximate refractive error values that are reliable enough to decide if further examination is needed at an eye care clinic.

Q6. What do the graduations and numbers on the scale mean?

The scale is marked from +4 diopter to -7 diopter. Diopter (D) denotes the corrective power of the glasses your eye requires.

The plus sign denotes farsightedness (Hyperopia), a condition in which you can see distant objects clearly, but objects nearby may be blurry. For instance, if FoFo reads +1 D, then you have one diopter of farsightedness. Meanwhile, +4 D indicates more farsightedness and you might need more powerful glasses.

The minus sign denotes nearsightedness (Myopia), a condition in which you can see objects near to you clearly, but objects farther away are blurry. For instance, -1 D indicates one diopter of nearsightedness and -4 D indicates more nearsightedness.

If FoFo reads 0 D, it means you have a normal vision (emmetropia) and do not require any correction. However, make sure that both the eyes are tested with FoFo for at least 3 times before drawing any conclusions.

Q7. The readings show only +0.5/-0.5 diopter error. Do I still need a further examination?

While a magnitude of 0.5 diopters indicates only a mild amount of refractive error, its consequence might depend on the individual's lifestyle and nature of work. For example, an office goer who spends most of the time indoors, working on a laptop, might not have significant difficulties with an error of -0.5 diopters (myopic - difficulty in seeing distant objects). But he/she might experience blurred vision while driving, at the theater, or occasionally suffer eye strain and headache. Therefore, it is recommended to get the eyes checked.

However, in children, even a mild refractive error reading must be taken very seriously. Read question no.8 to learn why.

Q8. How does the refractive error affect school children and how does FoFo help them?

As vision and learning are intimately related, school children with vision disorders are often wrongly labeled as slow learners or even as having ADHD. Not being able to see the blackboard (myopic) or read books clearly (hyperopic) can significantly affect their academic performance. Moreover, if left uncorrected, children might have a continual progression of their myopia throughout the school years. Therefore, even a mild refractive error in children must be corrected immediately.

Unfortunately, most kids don't realize their vision problem and hardly complain about it. Conducting vision screening programs in schools requires trained professionals, expensive equipment, and incurs cost and time. This often creates a roadblock in reaching these children in need, especially at rural schools. FoFo strives to change this by offering a simple, accessible and affordable solution. We train the rural school teachers to use FoFo on their students and screen them for early-onset refractive error. Those children with vision defects are recommended for further examination at the nearest eye care facility.

Q9. Can I make a donation instead of buying the device?

Of course! Please follow the link here to contribute.

Q10. What if the target does not become clear at any point? / Can FoFo measure astigmatism? / Can FoFo measure cylindrical power?

If the target always looks blurry, even after trying several times, probably you might have astigmatism. It is a type of refractive error caused by the irregularities in the cornea or lens. Astigmatism can be corrected by using glasses with 'cylindrical power'. As FoFo only gives the approximate 'spherical' error, it is not possible to know the astigmatic values. Nevertheless, if this is the case, the user will have to visit an eye care center for a detailed examination.

Q11. What's the durability of the device?

Though made of cardboard, FoFos are extremely durable if used and maintained properly. The telescopic tubes are built and tested to withstand around 500 cycles of extension and retraction. This means each FoFo can be used to check both the eyes of at least 250 people.

Q12. How to maintain the device?

Always keep FoFos in a dry and moisture-free place. Clean the tubes and outer lens with a soft cloth regularly and maintain them free of dirt and oil.

Q13. Is FoFo safe to use?

If used as intended, FoFos are safe for all age groups including children. However, as with any lens system, NEVER look at the sun or any bright light source through FoFo.