Interferometry and ophthalmics at the College of Optical Sciences

Greivenkamp, John E.; Williby, Gregory A.; Goodwin, Eric P.; Primeau, Brian; Heideman, Kyle C.; Micali, Jason D.; Spaulding, Russell T.

doi:10.1117/12.2064333

Cited by 2 publications

(2 citation statements)

References 15 publications

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“…56 This has led to the development of a number of instruments for characterizing the optical properties a soft contact lens. One of the first systems was a Mach-Zehnder interferometer for measuring the transmitted wavefront of the contact lens.…”

Section: Research Background and Historymentioning

confidence: 99%

Dual interferometer for dynamic measurement of corneal topography

Micali

Greivenkamp

2016

J. Biomed. Opt

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Abstract. The cornea is the anterior most surface of the eye and plays a critical role in vision. A thin fluid layer, the tear film, coats the outer surface of the cornea and serves to protect, nourish, and lubricate the cornea. At the same time, the tear film is responsible for creating a smooth continuous surface, where the majority of refraction takes place in the eye. A significant component of vision quality is determined by the shape of the cornea and stability of the tear film. A dual interferometer system for measuring the dynamic corneal topography is designed, built, verified, and qualified by testing on human subjects. The system consists of two coaligned simultaneous phase-shifting polarization-splitting Twyman-Green interferometers. The primary interferometer measures the surface of the tear film while the secondary interferometer tracks the absolute position of the cornea, which provides enough information to reconstruct the absolute shape of the cornea. The results are high-resolution and high-accuracy surface topography measurements of the in vivo tear film and cornea that are captured at standard camera frame rates.

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Section: Research Background and Historymentioning

confidence: 99%

Dual interferometer for dynamic measurement of corneal topography

Micali

Greivenkamp

2016

J. Biomed. Opt

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“…The actual transmission test was made using a Mach-Zehnder interferometer. 24 The whole lens reconstruction from LOCOH measurements along with a model of the Mach-Zehnder interferometer is used to simulate the transmission test. The simulated OPD can be directly compared to the measured transmitted OPD.…”

Section: Comparison With Transmission Testingmentioning

confidence: 99%

Low-coherence interferometer for contact lens surface metrology

Heideman

Greivenkamp

2016

Opt. Eng

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Abstract. Contact lens performance depends on a number of lens properties. Many metrology systems have been developed to measure different aspects of a contact lens, but none test the surface figure in reflection to subwavelength accuracy. Interferometric surface metrology of immersed contact lenses is complicated by the close proximity of the surfaces, low surface reflectivity, and instability of the lens. An interferometer to address these issues was developed and is described here. The accuracy of the system is verified by comparison of glass reference sample measurements against a calibrated commercial interferometer. The described interferometer can accurately reconstruct large surface departures from spherical with reverse raytracing. The system is shown to have residual errors better than 0.05% of the measured surface departure for high slope regions. Measurements made near null are accurate to λ∕20. Spherical, toric, and bifocal soft contact lenses have been measured by this system and show characteristics of contact lenses not seen in transmission testing. The measurements were used to simulate a transmission map that matches an actual transmission test of the contact lens to λ∕18.

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Interferometry and ophthalmics at the College of Optical Sciences

Cited by 2 publications

References 15 publications

Dual interferometer for dynamic measurement of corneal topography

Dual interferometer for dynamic measurement of corneal topography

Low-coherence interferometer for contact lens surface metrology

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