Self-test refraction tool powered by a smartphone.


Refraction Mobilized

Using a series of simple game-like interactions in a Virtual Reality headset, NETRA enables anyone anywhere to collect refractive measurements in terms of sphere, cylinder, axis of astigmatism and pupillary distance.

Get it on Google Play


Tips and Tricks

Express Prescriptions straight from the Phone

Instructions for Patients

Featured Benefits

Accuracy icon

Accuracy of 0.35D

NETRA is as accurate as top-tier auto refractors that can cost $45,000. It took 340 product iterations and 35,000 product tests to ensure this level of precision and control accommodation.

Accuracy icon
Test from anywhere icon
Test from anywhere icon


NETRA lets you take the reins no matter where you are, from a hospital in the urban jungle to a tent in the Amazon. It comes with an extended battery for 2 days of tests without charging.



The smartphone becomes a gateway for information between eye care providers and customers. On the Insight portal, patients and eye care providers navigate health information and converge to the best prescription.

Zero Maintenance
Zero Maintenance

Zero maintenance

Netra can drop from a maximum height of 1 meter without breaking or losing accuracy. Calibration happens automatically at every measurement. After two years selling the product, we have yet to see a broken NETRA.

Looking for ways to serve your high-end, repeat customers?
Here's an idea

Looking for ways to serve your high-end, repeat customers? Offer them a relaxed environment within your existing store. Using state-of-the art EyeNetra technology, provide them with a unique, personalized experience.

Technical Specifications


NETRA Refraction (Pat. Issued)

Accommodation Control

Fogging (Pat. Issued)

Light Source

Smartphone 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 (v1.01) is a Class 1 device exempt from premarket notification (510(k)


15°C to 40°C, in rel. humidity of 95% non-condensing


-20°C to 90°C, in rel. humidity of 95% non-condensing

Comparison among the Portable Auto-Refractors

Meet our Powerful Result Screen

More Videos, Cases and Testimonials

Got a question? We’ve got answers!

NETRA generates a recommended power, correcting for 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.

NETRA is designed for use by consumers under the supervision of an eye care professional. The professional can be physically present or on-line, and not necessarily in real-time. Our aim is to increase Eye Care Professional's reach by making optical measurements as easy to gather as possible

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.

We provide complimentary implementation training with our devices for customers. NETRA's intuitive interface and great ease-of-use requires minimal training. When you launch the app on your mobile device, a tutorial will walk you through everything you need to know.

No, NETRA is not an intended substitute for a full eye health exam. EyeNetra encourages you to consult with your optometrist or ophthalmologist.

NETRA is the world’s first smartphone vision diagnostic tool. Unlike traditional eyecare equipment, it enables highly accurate, self-administered tests with minimal training. Its sleek design and compact size allows it to travel anywhere, reducing the barriers to access and affordability for those in more remote areas of the world. Eye care providers can use it to expand their offerings and provide at-home screenings, mobile clinics or kiosks, workplaces testings, etc. By leveraging social networks and health data, NETRA keeps people connected to the right providers and vendors to ensure they get the care they need.

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Ready to try?

We offer a 10-day trial for all of our devices. If you simply don't like it, you can return the product to be eligible for a full refund.