Refractive Index Measurement System for a Contact Lens in a Natural Hydrated State

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A research collaboration between Lumetrics, Inc. and Johnson & Johnson.

Lumetrics, Inc., the leading provider of Ophthalmic metrology solutions is pleased to announce our latest project, a research collaboration between Lumetrics and Johnson & Johnson. The results were featured at the SPIE Photonics West 2019 exhibition poster session in San Francisco, CA on February 5-7.

Abstract: Accurate refractive index of a contact lens is one of the most important parameters needed to properly evaluate lens performance. Measurements of the refractive power and other optical properties of a lens are typically conducted in solution, and converted to in-air performance. Such an approach is very sensitive to errors in the refractive indices of both the lens and the solution. View the project here.

We have conducted measurements of the group refractive index (GRI) of hydrogel contact lenses at different wavelengths, from 530 to 670 nm, using time-domain low-coherence interferometer (LCI), based on a super-continuum light source (SCLS). We show that the proposed measurement equipment and technique will allow material phase RI characterization at visible wavelengths with accuracy of 0.003 or better.

About Lumetrics:

Lumetrics® is the leading metrology equipment manufacturer with total solution engineering expertise dedicated to the medical device, ophthalmic, glass, and film industries. Lumetrics® engineers are experts in designing custom metrology fixtures and data analysis packages for on-line or at-line thickness measurement applications.

Lumetrics’ metrology systems help customers improve yield, reduce costs, improve product quality, and meet regulatory compliance requirements.

For more information on Lumetrics’ diverse product line of non-contact thickness measurement systems, please email sales(at)

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Kristin Hart Daly
Lumetrics, Inc.
+1 (585) 214-2455 Ext: 126
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