NETRA Refraction For Anyone Anywhere - EyeNetra

NETRA Refraction For Anyone Anywhere

Using a series of simple game-like interactions in a Virtual Reality headset, NETRA enables anyone anywhere to collect their own refractive measurements. It's quick and easy to use in an office or in the field.

Eye care professionals can use the measurements to diagnose and prescribe for their patients.

What Does It Measure?

Farsightedness (Hyperopia)

Nearsightedness (Myopia)

Misshaped Eye (Astigmatism)

Pupillary Distance

Featured Benefits

As accurate as it gets

NETRA is just as accurate as top-tier autorefractors that cost up to $45,000. It took us 340 product iterations and 35,000 product tests to ensure precision and control accommodation.

The most affordable refractor yet

Exploiting off-the-shelf smartphones, we’ve designed NETRA to be affordable and accessible to just about anyone, anywhere. Doctors and patients can now overcome the last barrier for glasses.

User friendly to the extreme

No chin and forehead rest. No alignment or accommodation tricks. No need for specialized furniture. No need for dilation or cycloplegia.


NETRA let’s you take the reins no matter where you are, from an urban jungle to the Amazon, from a clean hospital room to a dirty tent in the desert.


The smartphone becomes a gateway for information exchange between eye care providers and customers.

Zero maintenance

Netra supports a drop of up to 1 meter without breaking or losing accuracy. Calibration happens automatically at every measurement.

Technical Specifications

NETRA (Pat. Issued)
Accommodation Control
Fogging (Pat. Pending)
Light Source
Smartphone (Samsung S4) Display (No Lasers)
Measuring Wavelengths
~550nm and ~650nm Simultaneously
Sphere Range
-12 to +5.5D, 0.25D increment
Cylindrical Range
0 to -7D, 0.25D increment
Axial Range
0 to 180, 1 degree increment
Interpupillary Distance Range
52 to 72mm, 0.5mm increment
Device Dimensions
8.5cm x 20cm x 20cm (436g)
Intended Patient Population
13 to 65 years old
External Processing Unit
Samsung S4
Dilation Required
Cycloplegic Requirements
Calibration Requirements
Office Illumination Requirements
None (Optically Sealed)
Specialized Furniture Requirements
None (Handheld)
FDA Status
NETRA is a Class 1 device exempt from 510(k)
Operation Temperature
15°C to 40°C, in rel. humidity of 95% non-condensing
Transportation Temperature
-20°C to 90°C, in rel. humidity of 95% non-condensing

Got a question? We’ve got answers!

  • Exactly what information does NETRA tell me?

    NETRA will generate a recommended power for your eyeglasses, correcting for nearsightedness, farsightedness, and astigmatism. More specifically, NETRA outputs the sphere (diopter), cylinder (diopter), and axis (degrees) as well as the measurement for the distance between eyes. NETRA does not measure any higher-order aberrations or quantify retinal conditions.

  • Who can use NETRA?

    NETRA is meant to be used by everyday consumers under the supervision of an eyecare professional. The professional can be with you or on-line, in real-time or not. Our aim is to increase the reach of Eye Care Professionals by making optical measurements easy to gather anywhere.

  • Has this been tested in the field...where?

    Yes, our devices have a track record of more than 40,000 usages worldwide: from IRB-approved research, to product development, and final releases. You can find a solid body of 19 scientific validations published in multiple venues including OSA's Fronteirs in Optics, Association for Research on Vision and Ophthalmology and ACM SIGGRAPHs. Here are some research links for reference:

    2015 - Monica M. S. Matsumoto, Vitor F. Pamplona, Matthias Hoffmann, Guilherme Uzejka, Nate Sharpe. NETRA-G: High-order Power Map and Low-order Lensmeter using a Smartphone Add-on. OSA's Frontiers in Optics 2015.
    2015 - Vitor Pamplona, Steven Tupin, Jorge Cuadros, Rahul Modi, Sowjanya Gowrisankaran. Validation of Confidence Levels for a Cell Phone-Based Refractor (NETRA-G). ARVO 2015, Denver CO.
    2014 - Vitor F Pamplona. NETRA-G: Towards a Subjective Self-Refraction. OSA's Frontiers in Optics 2014.
    2014 - Nadine Solaka, Rahul Modi, Hilary Gaiser, Vitor Pamplona, David Schafran, Ran He, Bruce D. Moore. Comparison of a New Prototype of NETRA-G Cellphone-Based Refraction with Subjective Refraction. ARVO 2014, Orlando, FL.
    2014 - Vitor F. Pamplona, Jonnadula Kartik, Shrikant Bharadwaj, Pradeep Nakhate, Nathaniel Sharpe. Identification and Comparison of Critical Axis Combinations for Estimating the Refractive Power of the Eye using NETRA. ARVO 2014, Orlando, FL.
    2012 - Bruce D. Moore, Nadine Solaka, Vitor Fernando Pamplona, David Schafran, Amy Canham, Ramesh Raskar, Hilary Gaiser. Comparison of a Novel Cell Phone-based Refraction Technique (NETRA-G) with Subjective Refraction. AAO 2012, Chicago, IL.
    2012 - Martha P. Lang, Helena M. Pakter, Lisia B. Ferreira, Ankit Mohan, Ramesh Raskar, Vitor F. Pamplona, Manoel M. Oliveira - Comparison of a Cell Phone-Based Refraction Technique (NETRA) With Auto-Refraction. ARVO 2012, Fort Lauderdale, US
    2012 - Vitor Pamplona, Manuel M. Oliveira, Daniel Aliaga, Ramesh Raskar. Tailored Displays to Compensate for Visual Aberrations. Proc. of SIGGRAPH 2012. ACM Transactions on Graphics 31 (4), 2012. Pages 87:1 - 12. 2012.
    2012 - Vitor F. Pamplona. Interactive Measurements and Tailored Displays for Optical Aberrations of the Human Eye. PhD Thesis. Porto Alegre: CPGCC-UFRGS, Jul. 2012.
    2011 - Vitor Pamplona, Erick Passos, Jan Zizka, Manuel M. Oliveira, Everett Lawson, Esteban Clua, Ramesh Raskar. CATRA: Interactive Measuring and Modeling of Cataracts. Proc. of SIGGRAPH 2011. ACM Transactions on Graphics 30 (4), 2011.
    2011 - Veerendranath Pesala, Sangeetha Srinivasan, Ethan Solomon, Vitor F. Pamplona, Manuel M. Oliviera, Ramesh Raskar, Shrikant Bharadwaj. Comparison of a Novel Cell Phone-Based Refraction Technique (NETRA) With Objective Clinical Retinoscopy. ARVO 2011 .
    2010 - Vitor F. Pamplona, Ankit Mohan, Manuel M. Oliveira, Ramesh Raskar. Low-cost and Portable tool for Measuring Eye Refractive Disorders using Active Participation. Proc. of 88th Annual Meeting of the American Academy of Optometry (AAO) , San Francisco.
    2010 - Vitor F. Pamplona, Ankit Mohan, Manuel M. Oliveira, Ramesh Raskar. Dual of Shack-Hartmann Optometry Using Mobile Phones. Proc. of Frontiers in Optics (FiO), Optical Society of America. Rochester, New York. 2010.
    2010 - Vitor F. Pamplona, Ankit Mohan, Manuel M. Oliveira, Ramesh Raskar. NETRA: Interactive Display for Estimating Refractive Errors and Focal Range. Proc. of SIGGRAPH 2010. ACM Transactions on Graphics 29 (4), 77:1 - 77:8, 2010.

  • A
  • NETRA full test video

  • How accurate is it?

  • Netra: Smartphone-powered Refraction

  • Tips for Using your EyeNetra Autorefractor

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NETRA Refraction For Anyone Anywhere
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