Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Uncertainty in Measurement: Reading Instruments

Uncertainty in Measurement: Reading Instruments

Counting is the type of measurement that is free from uncertainty, provided the number of objects being counted does not change during the process. Such measurements result in exact numbers. By counting the eggs in a carton, for instance, one can determine exactly how many eggs are there in the carton. Similarly, the numbers of defined quantities are also exact. For example, 1 foot is exactly 12 inches, 1 inch is exactly 2.54 centimeters, and 1 gram is exactly 0.001 kilograms. Quantities...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

A randomized crossover clinical trial of the Deseyne contact lens for presbyopia with extended depth of focus.

Optometry and vision science : official publication of the American Academy of Optometry·2026

Same author

Current Evidence on Options and Efficacy of Combination Therapy for Myopia Control-A Narrative Review.

Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)·2026

Same author

Author's response.

Optometry and vision science : official publication of the American Academy of Optometry·2026

Same author

IMI-Interventions for Controlling Myopia Onset and Progression 2025.

Investigative ophthalmology & visual science·2025

Same author

IMI-2025 Digest.

Investigative ophthalmology & visual science·2025

Same author

Myopia Correction, Myopia Control and Myopia Management: Definitions and Recommended Usage.

Investigative ophthalmology & visual science·2025

Search research articles

Related Experiment Video

Updated: May 9, 2026

$Comparison of Agreement and Accuracy using Binocular Wavefront Optometer with Autorefractor and Phoropter$

Comparison of Agreement and Accuracy using Binocular Wavefront Optometer with Autorefractor and Phoropter

Published on: September 16, 2025

Agreement between a partial coherence interferometer and 2 manual keratometers.

Mark A Bullimore¹, Tobias Buehren, Wilfried Bissmann

¹From the University of Houston (Bullimore), College of Optometry, Houston, Texas, USA, and Carl Zeiss Meditec AG (Buehren, Bissmann), Jena, Germany.

Journal of Cataract and Refractive Surgery

|July 24, 2013

Summary

This summary is machine-generated.

The partial coherence interferometry (PCI) device shows excellent agreement for measuring corneal astigmatism and axis with a 2-position manual keratometer. This PCI device is suitable for toric intraocular lens calculations.

More Related Videos

Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating

Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating

Published on: October 11, 2016

The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry

The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry

Published on: August 12, 2013

Related Experiment Videos

Last Updated: May 9, 2026

$Comparison of Agreement and Accuracy using Binocular Wavefront Optometer with Autorefractor and Phoropter$

Comparison of Agreement and Accuracy using Binocular Wavefront Optometer with Autorefractor and Phoropter

Published on: September 16, 2025

Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating

Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating

Published on: October 11, 2016

The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry

The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry

Published on: August 12, 2013

Area of Science:

Ophthalmology
Optometry
Biomedical Optics

Background:

Astigmatism measurement is crucial for accurate toric intraocular lens (IOL) implantation.
Partial Coherence Interferometry (PCI) offers a non-contact method for ocular biometry.
Validation of new devices against established methods is essential for clinical adoption.

Purpose of the Study:

To assess the repeatability and validity of a novel partial coherence interferometry (PCI) device for measuring corneal astigmatism in patients.
To compare the performance of the PCI device against two different manual keratometers.

Main Methods:

Prospective and retrospective observational studies were conducted.
Agreement was assessed between the PCI device and 1-position and 2-position manual keratometers for corneal power, astigmatic power, and axis.
Interinstrument and interoperator reproducibility were evaluated, along with device repeatability.

Main Results:

The PCI device demonstrated excellent agreement with the 2-position manual keratometer for astigmatism and axis.
Agreement for astigmatism and axis with the 1-position manual keratometer was also good, though it yielded slightly lower astigmatism estimates.
The PCI device exhibited superior repeatability compared to both manual keratometers.

Conclusions:

The PCI device demonstrates high accuracy and repeatability in measuring corneal astigmatism and axis.
Excellent agreement with a 2-position manual keratometer supports its use in clinical practice.
The PCI device is a reliable tool for calculating toric intraocular lenses.