Anterior Eye Segment Measurements, Corneal Thickness Measurement, Epithelial Thickness Measurement
Conditions
Keywords
VHF digital ultrasound, Corneal thickness, Epithelial thickness, Angle diameter, Sulcus diameter, Anterior chamber depth, Repeatability, Reproducibility
Brief summary
The purpose of this study is to evaluate the repeatability and reproducibility of corneal (including corneal, epithelial, stromal, and LASIK flap thickness) and anterior segment measurements using the ArcScan Insight 100 very high-frequency digital ultrasound arc-scanner.
Detailed description
Very high-frequency (VHF) digital ultrasound was first used in 1993 to obtain images of the cornea (the window at the front of the eye) and anterior segment (the space behind the cornea including the iris and the lens). A commercially available instrument, called the Artemis 2, has been used in routine clinical practice since 2001. The Artemis 2 was CE approved as well as having FDA approval (the US equivalent of the CE mark). The ArcScan Insight 100 VHF digital ultrasound scanner is a new instrument so does not yet have a CE mark. However, the ArcScan Insight 100 is an upgraded version of the Artemis 2, so any differences are improvements to components, but the measurement method remains essentially the same. 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) of the ArcScan Insight 100 device for measuring corneal and anterior segment parameters.
Interventions
The ArcScan Insight 100 VHF digital ultrasound scanner that 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.
Sponsors
Arcscan, Inc.
London Vision Clinic
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
21 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
Only patients who are medically suitable for corneal 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 repeatability and reproducibility phase using normal eyes of the study: * Eyes with no ocular pathology * Eyes with no previous ocular or corneal surgery For the repeatability and reproducibility phase using post-LASIK eyes of the study: • Eyes between 3 and 9 months after LASIK or SMILE For the comparison of ArcScan Insight 100 VHF digital ultrasound with RTVue OCT • Either eyes before or after corneal refractive surgery
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Repeatability of ArcScan Insight 100 corneal scans in normal eyes (standard deviation) | 1 day | The standard deviation of 5 repeated measurements for corneal thickness, epithelial thickness, and stromal thickness in normal eyes with no previous corneal surgery |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Reproducibility of ArcScan Insight 100 corneal scans in normal eyes (between-operator standard deviation) | 1 day | The between-operator standard deviation of 5 repeated measurements for each operator for corneal thickness, epithelial thickness, and stromal thickness in normal eyes with no previous corneal surgery |
| Repeatability of ArcScan Insight 100 anterior segment scans in normal eyes (standard deviation) | 1 day | The standard deviation of 5 repeated measurements for anterior segment dimensions: angle diameter, sulcus diameter, anterior chamber depth, and lens rise from the zonular plane in normal eyes with no previous corneal surgery |
| Reproducibility of ArcScan Insight 100 anterior segment scans in normal eyes (between-operator standard deviation) | 1 day | The between-operator standard deviation of 5 repeated measurements for each operator for anterior segment dimensions: angle diameter, sulcus diameter, anterior chamber depth, and lens rise from the zonular plane in normal eyes with no previous corneal surgery |
| Repeatability of ArcScan Insight 100 corneal scans in eyes after corneal laser refractive surgery (standard deviation) | 1 day | The standard deviation of 5 repeated measurements for corneal thickness, epithelial thickness, stromal thickness, flap thickness, and residual stromal thickness in eyes after corneal laser refractive surgery |
| Reproducibility of ArcScan Insight 100 corneal scans in eyes after corneal laser refractive surgery (between-operator standard deviation) | 1 day | The between-operator standard deviation of 5 repeated measurements for each operator for corneal thickness, epithelial thickness, stromal thickness, flap thickness, and residual stromal thickness in eyes after corneal laser refractive surgery |
Countries
United Kingdom
Outcome results
None listed