Evaluation of Letters Versus Numbers (ELEVEN) Study (ELEVEN)

August 19, 2020 updated by: Dr. Nicholas Fung, The University of Hong Kong

Evaluation of Letters Versus Numbers (ELEVEN) Study: ETDRS Visual Acuity Chart Performance in an English Alphabet Illiterate Population

This is a prospective randomised controlled trial to determine the performance of Best Corrected Visual Acuity (BCVA) scores using the ETDRS number chart were compared with ETDRS alphabet chart in healthy eyes of patients who do not recognise the English alphabet.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

BACKGROUND: The measurement of visual acuity is important in the clinical setting to assess visual function and treatment response, while in research to provide objective clinical outcomes. The current gold standard for visual acuity measurement in most research studies, including major clinical trials, is the Early Treatment Diabetic Retinopathy Study (ETDRS) chart designed by Bailey and Lovie. However, this may not be suitable for participants who are illiterate. Alternatives exist, including the ETDRS numbers chart, Landolt C chart and Tumbling E chart. Existing studies show that the Landolt C and Tumbling E charts are alternatives with agreement with ETDRS letters chart in healthy and diseased eyes. However, the charts are limited by their 25% (if four orientations) or 12.5% (if eight orientations) chance of guessing the orientation of the letter.

The ETDRS numbers chart may overcome this limitation, as it uses five unique numbers instead of a single rotating letter. There are few studies evaluating the different types of visual acuity measurement among those unfamiliar with the English alphabet. Though one study shows high repeatability and agreement between the ETDRS letters and numbers charts in healthy and diseased eyes of English literate individuals and shorter testing duration when using the numbers chart, this finding has not been validated in individuals unfamiliar with the English alphabet. This study aims to evaluate how the ETDRS letters and numbers charts compare in individuals unfamiliar with the English alphabet.

METHODS: Eligible subjects were divided into 2 groups according to level of literacy. Literacy was determined by self-reported exposure to the English alphabet and recognition of the 10 Sloan letters (C, D, H, K, N, O, R, S, V, and Z). Subjects included were classified into the 2 groups: group A, with no exposure to the English alphabet and recognition of <6/10 letters, and group B, with exposure to the English alphabet and recognition of ≥6/10 letters.

Testing: Each subject underwent 2 rounds of BCVA measurements using 2 types of ETDRS charts in randomized sequence as follows: LN or NL (L = ETDRS letters chart, N = ETDRS numbers chart) from Precision Vision® (PV). The randomization of the testing sequence was performed by a study coordinator independent of study recruiter, optometrist or investigator. Sequentially numbered, opaque and sealed envelopes were used for allocation concealment and opened by the optometrist prior to testing.

The tests were performed and recorded by a single optometrist in the same testing room with similar lighting conditions. For every round of testing, the right eye was examined first, followed by the left eye. For the right eye, numbers chart (PV No. 2702A) and letters chart (PV No. 2173) were used. For the left eye, the numbers chart (PV No. 2714A) and letters chart (PV No. 2174) were used. Different charts (with the same optotypes but in different order) were used for right and left eyes to minimize the effect of learning between consecutive tests.

Study Type

Interventional

Enrollment (Actual)

59

Phase

  • Not Applicable

Contacts and Locations

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

Study Locations

  • Hong Kong
      • Hong Kong, Hong Kong, 000000
        • HKSDS Program

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

50 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. Hong Kong residents
  2. Age 50 years or above
  3. Attending Southern District Screening program

Exclusion Criteria:

  1. BCVA 20/200 or below
  2. Any clinically relevant ocular disease that might affect visual acuity

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

  • Primary Purpose: Diagnostic
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: English alphabet illiterate group
Individuals with no self-reported understanding of English alphabet and recognition of <6/10 Sloan Letters
Diagnostic test: Visual acuity assessment by ETDRS charts
All participants must complete VA measurement of both eyes using 2 charts including the ETDRS letters chart and ETDRS numbers chart.
Active Comparator: English alphabet literate group
Individuals with self-reported understanding of English alphabet and recognition of ≥6/10 Sloan Letters
Diagnostic test: Visual acuity assessment by ETDRS charts
All participants must complete VA measurement of both eyes using 2 charts including the ETDRS letters chart and ETDRS numbers chart.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
BCVA Measurements
Time Frame: 1 day
Assessment of BCVA using ETDRS numbers and letters chart and its comparison between the testing groups and intervention methods. All visual acuity tests were performed at 3 metres with at least 15 seconds between each chart. Subjects were asked to read as many optotypes as possible according to the ICO Visual Acuity Measurement Standard.
1 day
Testing Duration
Time Frame: 1 day
Assessment of testing duration using ETDRS numbers and letters and its comparison between the testing groups and intervention methods. The testing durations of each visual acuity test were measured and recorded by a single timekeeper with a standard digital chronometer.
1 day

Collaborators and Investigators

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

Sponsor

The University of Hong Kong

Investigators

  • Principal Investigator: Nicholas Fung, Department of Ophthalmology, HKU

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 (Actual)

August 1, 2019

Primary Completion (Actual)

January 31, 2020

Study Completion (Actual)

January 31, 2020

Study Registration Dates

First Submitted

August 17, 2020

First Submitted That Met QC Criteria

August 19, 2020

First Posted (Actual)

August 20, 2020

Study Record Updates

Last Update Posted (Actual)

August 20, 2020

Last Update Submitted That Met QC Criteria

August 19, 2020

Last Verified

August 1, 2020

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • ELEVEN

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

Yes

IPD Plan Description

By request to corresponding users

IPD Sharing Time Frame

Within 1 year of publication

IPD Sharing Access Criteria

For research publisher

IPD Sharing Supporting Information Type

  • Study Protocol
  • Statistical Analysis Plan (SAP)
  • Informed Consent Form (ICF)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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