NCT03473847 - Repeatability, Reproducibility and Comparison of Cirrus OCT, RTVue OCT, MS-39 OCT, and Insight 100 VHFDU | Crick

Overview

The purpose of this study is to evaluate the repeatability and reproducibility of corneal, epithelial, and LASIK flap thickness using the Carl Zeiss Meditec Cirrus HD OCT 5000, Optovue RTVue OCT, CSO MS-39 OCT, and ArcScan Insight 100 very high-frequency digital ultrasound arc-scanner.

Very high-frequency (VHF) digital ultrasound was first used in 1993 to obtain images and measure the thickness of the cornea (the window at the front of the eye) and the layers within the cornea, such as the epithelium (the layer of skin on the surface of the cornea). A commercially available instrument, known as the Artemis, has been used in routine clinical practice since 2001. The ArcScan Insight 100 VHF digital ultrasound scanner is an updated version, which obtained CE mark in 2016. Optical coherence tomography (OCT) is another method of measuring the thickness of the cornea and the corneal epithelium. OCT has been used for measuring corneal thickness since 1997 and the technology had evolved to also measure epithelial thickness since 2012. There are currently three OCT scanners capable of measuring epithelial thickness; Carl Zeiss Meditec Cirrus HD OCT 5000, Optovue RTVue OCT, CSO MS-39 OCT. The aim of the study is to establish the repeatability (i.e. the variability in measurements taken by a single examiner during a single visit) and reproducibility (i.e. the variability in measurements taken in the same conditions between two examiners) for each of the four devices for measuring corneal thickness and epithelial thickness.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Enrollment

242

Conditions

Corneal Thickness Measurement Epithelial Thickness Measurement LASIK Flap Thickness Measurement SMILE Cap Thickness Measurement

Interventions

ArcScan Insight 100 very high-frequency digital ultrasoundDEVICE

The ArcScan Insight 100 VHF digital ultrasound scanner can measure individual layers within the cornea with very high precision, as well as being able to image the interior of the eye including the chamber between the iris and the cornea, the lens and other structures behind the iris. The ArcScan Insight 100 device is a digital ultrasound scanner, meaning that it uses ultrasound waves to measure parameters of the eye. The Insight examination involves the patient sitting in front of the ultrasound unit and looking through a disposable goggle-like eyepiece at a light source. Warm sterile balanced saline solution (like natural tears) are used to fill the space between the light source and the eye, to allow ultrasound transmission. There is no contact between the instrument and the eye other than being immersed in this water bath.

Carl Zeiss Meditec Cirrus HD OCT 5000DEVICE

The Cirrus HD OCT 5000 uses high definition spectral domain optical coherence tomography (OCT) to measure anatomical structures of the eye. OCT is non-contact and uses light, rather than ultrasound, to obtain cross-sectional images. An OCT scan involves the patient sitting in front of the device, placing their chin on a chin-rest and fixating on a light source. Nothing comes into contact with the eye and the patient is only aware of the instrument rotating in front of them.

Eligibility

Sex: ALLMin age: 21 YearsMax age: 70 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: Only patients who are medically suitable for corneal laser refractive surgery can be included in the study. As general inclusion criteria the following aspects are defined: * Subjects should be 21 years of age or older. * Contact lens wearers must stop wearing their contact lenses at least four weeks per decade of wear before baseline measurements in case of hard contact lenses and one week before baseline measurements in case of soft contact lenses. * Patient will be able to understand the patient information and willing to sign an informed consent. For the normal eye populations: * Eyes with no ocular pathology * Eyes with no previous ocular or corneal surgery For the post-op eye populations: • Eyes between 3 and 9 months after LASIK or SMILE Exclusion Criteria: * Previous ocular or corneal surgery (for normal eyes) * Patient not being able to tolerate local or topical anesthesia * Patient has active conjunctivitis or any active ocular infection or inflammation * Patient has a corneal ulcer * Patient has an open wound on the corneal epithelium * Patient has compromised epithelium (e.g. ≥Grade 3 superficial punctate keratitis) * Pregnancy

Locations (1)

London Vision Clinic

London, United Kingdom

Outcomes

Primary Outcomes

Repeatability and reproducibility of Cirrus HD OCT 5000 corneal scans in normal eyes (standard deviation)

The within-observer standard deviation (repeatability) and between-observer standard deviation (reproducibility) calculated by ANOVA for 5 repeated measurements by two observers of corneal thickness and epithelial thickness in normal eyes with no previous corneal surgery

Time frame: 10 minutes (5 minutes per observer)

Repeatability and reproducibility of RTVue OCT corneal scans in normal eyes (standard deviation)

The within-observer standard deviation (repeatability) and between-observer standard deviation (reproducibility) calculated by ANOVA for 5 repeated measurements by two observers of corneal thickness and epithelial thickness in normal eyes with no previous corneal surgery

Time frame: 10 minutes (5 minutes per observer)

Repeatability and reproducibility of MS-39 OCT corneal scans in normal eyes (standard deviation)

The within-observer standard deviation (repeatability) and between-observer standard deviation (reproducibility) calculated by ANOVA for 5 repeated measurements by two observers of corneal thickness and epithelial thickness in normal eyes with no previous corneal surgery

Time frame: 10 minutes (5 minutes per observer)

Repeatability and reproducibility of Insight 100 VHF digital ultrasound corneal scans in normal eyes (standard deviation)

The within-observer standard deviation (repeatability) and between-observer standard deviation (reproducibility) calculated by ANOVA for 5 repeated measurements by two observers of corneal thickness and epithelial thickness in normal eyes with no previous corneal surgery

Time frame: 30 minutes (15 minutes per observer)

Repeatability and reproducibility of Cirrus HD OCT 5000 corneal scans in post-op eyes (standard deviation)

The within-observer standard deviation (repeatability) and between-observer standard deviation (reproducibility) calculated by ANOVA for 5 repeated measurements by two observers of corneal thickness and epithelial thickness in eyes between 3 and 9 months after corneal laser refractive surgery