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Proceedings Paper

Measurement accuracy of a stressed contact lens during its relaxation period
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Paper Abstract

We examine the dioptric power and transmitted wavefront of a contact lens as it releases its handling stresses. Handling stresses are introduced as part of the contact lens loading process and are common across all contact lens measurement procedures and systems.

The latest advances in vision correction require tighter quality control during the manufacturing of the contact lenses. The optical power of contact lenses is one of the critical characteristics for users. Power measurements are conducted in the hydrated state, where the lens is resting inside a solution-filled glass cuvette. In a typical approach, the contact lens must be subject to long settling times prior to any measurements. Alternatively, multiple measurements must be averaged. Apart from potential operator dependency of such approach, it is extremely time-consuming, and therefore it precludes higher rates of testing.

Comprehensive knowledge about the settling process can be obtained by monitoring multiple parameters of the lens simultaneously. We have developed a system that combines co-aligned a Shack-Hartmann transmitted wavefront sensor and a time-domain low coherence interferometer to measure several optical and physical parameters (power, cylinder power, aberrations, center thickness, sagittal depth, and diameter) simultaneously. We monitor these parameters during the stress relaxation period and show correlations that can be used by manufacturers to devise methods for improved quality control procedures.

Paper Details

Date Published: 19 February 2018
PDF: 12 pages
Proc. SPIE 10474, Ophthalmic Technologies XXVIII, 1047423 (19 February 2018); doi: 10.1117/12.2290435
Show Author Affiliations
David C. Compertore, Lumetrics, Inc. (United States)
Filipp V. Ignatovich, Lumetrics, Inc. (United States)

Published in SPIE Proceedings Vol. 10474:
Ophthalmic Technologies XXVIII
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

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