Repeatability and Reproducibility of the ArcScan Insight 100 VHF Digital Ultrasound

Repeatability and Reproducibility of Corneal and Anterior Segment Measurements by ArcScan Insight 100 Very High-frequency Digital Ultrasound

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.

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.

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