NCT02810665

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

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

• Status: Unknown
• Phase: —
• Study type: Observational
• Enrollment: 180 (estimated)
• Sponsor: Chiang Mai University · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

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.

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.

Conditions

• Visual Nonspecific

Interventions

Type	Name	Description
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.

Timeline

• Start date: 2015-07-01
• Primary completion: 2016-07-01
• Completion: 2016-07-01
• First posted: 2016-06-23
• Last updated: 2016-06-23

Locations

1 site across 1 country: Thailand