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Completed

NCT Number: NCT02429609

Exploring the Psychophysics of Keratoconus Using the Moorfields Acuity Chart

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.

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Key information

Conditions

Keratoconic Subjects

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Moorfields Acuity Chart

Device

Primary outcomes

  1. 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

Secondary outcomes

  1. 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

Sponsors and collaborators

Lead sponsor

Moorfields Eye Hospital NHS Foundation Trust

Other

Registry information

Acronym: MACK

Important dates

Study start
2015
Primary completion
2016
Study completion
2016
First posted
Apr 29, 2015
Registry last updated
Apr 12, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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