Exploring the Psychophysics of Keratoconus Using the Moorfields Acuity Chart (MACK)

April 4, 2022 updated by: Moorfields Eye Hospital NHS Foundation Trust
The measurement of visual acuity is made using black letters of varying size superimposed on a uniform white background. The objective is to determine the smallest letter, or optotype, that can be correctly identified. One limitation of current tests is the variability of measurements, this making it difficult for clinicians to determine if changes in visual acuity are related to ocular disease. This variability has been attributed to the design of current optotypes, in particular their differing legibilities. Our group has recently demonstrated that a new type of letter chart (Moorfields Acuity Chart), containing letters with a black core and a white border presented on a grey background, reduces the variability of visual acuity measurements. In this study the investigators wish to determine if changes in vision owing to keratoconus, a disease that causes the cornea to adopt an irregular shape, may be detected more easily using the Moorfields Acuity Chart compared with conventional letter charts.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
80

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 35 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Keratoconic subjects (50):

  • Age 18-40 years.
  • The presence of keratoconus in at least one eye.
  • The absence of significant media opacities (e.g. cataract, corneal scarring).
  • The absence of any other ocular pathology (e.g. glaucoma, diabetic retinopathy, uveitis).
  • The absence of amblyopia in the test eye.
  • No previous ocular surgery (e.g. corneal crosslinking, cataract surgery, etc.)
  • Best corrected visual acuity better than or equal to 6/60 (1.0 logMAR).
  • Pupil diameter ≥3 mm and ≤7 mm in normal room illumination.

Healthy subjects (30):

  • Age 18-35 years.
  • The absence of clinically significant keratoconus.
  • The absence of significant media opacities. (e.g. cataract, corneal scarring).
  • The absence of any other ocular pathology (e.g. glaucoma, diabetic retinopathy, uveitis).
  • The absence of amblyopia in the test eye.
  • No previous ocular surgery (e.g. corneal crosslinking, cataract surgery, etc.)
  • Best corrected visual acuity better than or equal to 6/9 (0.1 logMAR).
  • Pupil diameter ≥3 mm and ≤7 mm in normal room illumination.

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: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Keratoconic subjects
  1. Short clinical interview (Questions pertaining to ocular and systemic health, medications, family history and date of birth). (approx. 2 minutes)
  2. Visual acuity measurement using EDTRS chart at 4 m (approx. 4 minutes)
  3. Refraction: retinoscopy and subjective, at 4m (approx. 10 minutes)
  4. Anterior eye examination (approx. 4 minutes)
  5. Fundus examination using binocular indirect ophthalmoscopy or a standard ophthalmoscope - to screen for eye disease that is likely to affect visual ability in this study. (approx. 5 minutes)
  6. Corneal topography measurement with an Oculus Pentacam (Oculus Gmbh., Germany). (approx. 5 minutes)

Two measurements of visual acuity will be made:

  1. Standard ETDRS logMAR acuity measurement (5 minutes)
  2. Vanishing Optotype logMAR acuity measurement (5 minutes)
Device: Moorfields Acuity Chart
Experimental: Healthy subjects
  1. Short clinical interview (Questions pertaining to ocular and systemic health, medications, family history and date of birth). (approx. 2 minutes)
  2. Visual acuity measurement using EDTRS chart at 4 m (approx. 4 minutes)
  3. Refraction: retinoscopy and subjective, at 4m (approx. 10 minutes)
  4. Anterior eye examination (approx. 4 minutes)
  5. Fundus examination using binocular indirect ophthalmoscopy or a standard ophthalmoscope - to screen for eye disease that is likely to affect visual ability in this study. (approx. 5 minutes)
  6. Corneal topography measurement with an Oculus Pentacam (Oculus Gmbh., Germany). (approx. 5 minutes)

Two measurements of visual acuity will be made:

  1. Standard ETDRS logMAR acuity measurement (5 minutes)
  2. Vanishing Optotype logMAR acuity measurement (5 minutes)
Device: Moorfields Acuity Chart

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
The relative difference in visual acuity measurement between subjects with and without keratoconus when examined with different types of visual acuity chart.
Time Frame: 9 months
9 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
The relationship (if any) between optical imperfections (high order aberrations) and measurements of visual acuity when measured using different test chart designs.
Time Frame: 9 months
9 months

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Moorfields Eye Hospital NHS Foundation Trust

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 15, 2015

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 30, 2016

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 30, 2016

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 9, 2015

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 24, 2015

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 29, 2015

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 12, 2022

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 4, 2022

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2022

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • ANDO1009

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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