Repeatability and Reproducibility of Lens Zonule Length Measurement Using ArcScan Insight 100

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to evaluate the intra-examiner repeatability and inter-examiner reproducibility in lens zonule length measurements using very high-frequency (VHF) digital ultrasound (ArcScan Insight 100).

Official Title
-----------------
Repeatability and Reproducibility of Lens Zonule Length Measurement Using ArcScan Insight 100 Very High-frequency Digital Ultrasound

Conditions
-----------------
Zonule of Zinn Abnormality, Zonular Cataract

Intervention / Treatment
-----------------
* Device: ArcScan Insight 100 very high-frequency digital ultrasound


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Subjects with no ocular disease except ametropia Subjects will be able to understand and willing to sign an informed consent Exclusion Criteria: Previous ocular surgery Subjects not being able to tolerate or not willing to use pilocarpine eye drops Subjects has active ocular infection or inflammation Subjects not being able to look steadily Subjects not being able to open eyes wide in sterile saline even after topical anesthesia
Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Normal eyes<br> | Device: ArcScan Insight 100 very high-frequency digital ultrasound<br>* The Insight-100 (ArcScan Inc., Golden, CO, USA) employs the high-frequency B-scan in the assessment of anterior segment parameters. Anormal saline coupling medium is formed with a disposable eyepiece between the 50 MHz transducer and the eye. The instrument moves the transducer in an arc so that the beam axis maintains approximate normality to the surface of the eye. The frequencies of cornea, anterior chamber, and lens are 60 MHz, 50 MHz and 50 MHz, respectively. The maximum arc scanning range is 70 degrees, and there is a linear scanning range of 29mm. The axial and lateral resolutions are 35 μm and 65 μm, respectively. It can measure structures behind the iris, including lens zonule.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Repeatability of ArcScan Insight 100 zonule scans in normal eyes (standard deviation and coefficient of variation) | First, three images will be obtained under'capsule model'using ArcScan Insight 100, and the length of zonule will be measured with built-in software by operator A. Operator B then performed the measurements using the same procedure and technique. The standard deviation and coefficient of variation of 3 repeated measurements for zonule length. will be calculated. | 1 day | 
| Reproducibility of ArcScan Insight 100 zonule scans in normal eyes | First, three images will be obtained under'capsule model'using ArcScan Insight 100, and the length of zonule will be measured with built-in software by operator A. Operator B then performed the measurements using the same procedure and technique. The intraclass correlation is used to evaluate the difference between operator A and operator B. | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Repeatability of zonule length measurement with the built-in software (the intraclass correlation) | After a 1-month period, operator A and operator B will measure the zonule length again. The intraclass correlation is used to evaluate the difference between the two repeated measurements of one same image by Operator A or Operator B. | 1 month |