Repeatability and Concordance of VA Measured With ETDRS Numeric , Landolt C, and Letter Charts in Thai Individuals

June 20, 2016 updated by: Voraporn Chaikitmongkol, Chiang Mai University

Repeatability and Concordance of Visual Acuity Level Measured With ETDRS Numeric Charts, ETDRS Landolt C Charts, and Original ETDRS Letter Visual Acuity Charts in Thai Individuals

This is a cross-sectional study to determine the repeatability and concordance of visual acuity level measured with the original ETDRS letter, ETDRS Landolt C, and ETDRS numeric chart in Thai individuals.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Detailed Description

The ETDRS visual acuity chart has been used as a standard visual acuity measurement chart in ophthalmic clinical trials due to its proven high repeatability comparing to other visual acuity chart. However, the original ETDRS alphabet chart could not be used in every individual around the world, especially those who are non-english speakers. Landolt C chart has been a recommended chart to test visual acuity in those living in a country where English is not a common language, however, some difficulties including right-left confusion occurred when testing with the Landolt C chart, leading to the unreliable results of visual acuity measurement using the Landolt C chart. Recently, the ETDRS numeric chart was introduced by some medical equipment companies but there is limited information regarding the repeatability and concordance of the new ETDRS numeric chart comparing to the original ETDRS alphabet and Landolt C chart.

Therefore, this study aims to determine the repeatability and concordance of visual acuity level measured with the original ETDRS alphabet, the ETDRS Landolt C, and the ETDRS numeric chart. Results from this study would be able to suggest an appropriate ETDRS chart to be used in clinical studies in Thailand or other countries where English is not the native language.

Study Type

Observational

Enrollment (Anticipated)

180

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Thailand
    • Chiang Mai
      • Muang Chiang Mai, Chiang Mai, Thailand, 50200

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Participants with normal vision (VA of 20/20 to 20/25) and decreased vision (VA of 20/32 to 20/200 due to cataract, diabetic macular edema, or age-related macular degeneration) who gave consent to participate in this study

Description

Inclusion Criteria:

  • Thai nationality
  • More than 18 years of age
  • Educational level: at least high school
  • Able to read English alphabet

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Case-Only
  • Time Perspectives: Cross-Sectional

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Normal vision group
Individuals with VA 20/20 to 20/25
Behavioral: Visual acuity measurement by ETDRS chart
All participants must complete VA measurement of the study eye using 3 charts including the original ETDRS alphabet, ETDRS Landolt C, and ETDRS numeric charts for 2 times, at least 30 minutes apart.
Impaired vision group
Individuals with impaired vision: VA of 20/32 to 20/200 due to either cataract, diabetic macular edema, or age-related macular degeneration
Behavioral: Visual acuity measurement by ETDRS chart
All participants must complete VA measurement of the study eye using 3 charts including the original ETDRS alphabet, ETDRS Landolt C, and ETDRS numeric charts for 2 times, at least 30 minutes apart.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Concordance of VA tested with ETDRS alphabet, Landolt C and numeric visual acuity charts
Time Frame: Day 1
Day 1

Secondary Outcome Measures

Outcome Measure
Time Frame
Repeatability of VA tested with ETDRS alphabet, Landolt C and numeric visual acuity charts
Time Frame: Day 1
Day 1
Differences in testing duration of VA measurement across the 3 ETDRS charts
Time Frame: Day 1
Day 1

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Chiang Mai University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2015

Primary Completion (Anticipated)

July 1, 2016

Study Completion (Anticipated)

July 1, 2016

Study Registration Dates

First Submitted

June 16, 2016

First Submitted That Met QC Criteria

June 20, 2016

First Posted (Estimate)

June 23, 2016

Study Record Updates

Last Update Posted (Estimate)

June 23, 2016

Last Update Submitted That Met QC Criteria

June 20, 2016

Last Verified

June 1, 2016

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • OPT-2558-03133

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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