MACK: Exploring the Psychophysics of Keratoconus Using the Moorfields Acuity Chart

Sponsor

Moorfields Eye Hospital NHS Foundation Trust (Other)

Overall Status

Completed

CT.gov ID

NCT02429609

Collaborator

(none)

Enrollment

Arms

12.5

Actual Duration (Months)

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Keratoconic Subjects	Device: Moorfields Acuity Chart	N/A

Study Design

Study Type:

Interventional

Actual Enrollment :

80 participants

Allocation:

Non-Randomized

Intervention Model:

Single Group Assignment

Intervention Model Description:

This in a basic science exploratory study to examine the effect of keratoconus on visual acuity as measured using pseudo-high-pass filtered optotypes. The MAC will be compared with the standard charts currently used to monitor visual acuity (logMAR chart) and contrast sensitivity (Pelli-Robson). "Researcher effects" and "researcher bias" will be controlled by setting a written protocol for all testing procedures. Each procedure will be standardised and random checks will be made by the chief investigator on all anonymous record sheets. Neither the chief investigator nor the co-researchers will act as participants for this study.This in a basic science exploratory study to examine the effect of keratoconus on visual acuity as measured using pseudo-high-pass filtered optotypes. The MAC will be compared with the standard charts currently used to monitor visual acuity (logMAR chart) and contrast sensitivity (Pelli-Robson). "Researcher effects" and "researcher bias" will be controlled by setting a written protocol for all testing procedures. Each procedure will be standardised and random checks will be made by the chief investigator on all anonymous record sheets. Neither the chief investigator nor the co-researchers will act as participants for this study.

Masking:

None (Open Label)

Primary Purpose:

Basic Science

Official Title:

Exploring the Psychophysics of Keratoconus Using the Moorfields Acuity Chart

Actual Study Start Date :

Apr 15, 2015

Actual Primary Completion Date :

Apr 30, 2016

Actual Study Completion Date :

Apr 30, 2016

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Keratoconic subjects Short clinical interview (Questions pertaining to ocular and systemic health, medications, family history and date of birth). (approx. 2 minutes) Visual acuity measurement using EDTRS chart at 4 m (approx. 4 minutes) Refraction: retinoscopy and subjective, at 4m (approx. 10 minutes) Anterior eye examination (approx. 4 minutes) 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) Corneal topography measurement with an Oculus Pentacam (Oculus Gmbh., Germany). (approx. 5 minutes) Two measurements of visual acuity will be made: Standard ETDRS logMAR acuity measurement (5 minutes) Vanishing Optotype logMAR acuity measurement (5 minutes)	Device: Moorfields Acuity Chart
Experimental: Healthy subjects Short clinical interview (Questions pertaining to ocular and systemic health, medications, family history and date of birth). (approx. 2 minutes) Visual acuity measurement using EDTRS chart at 4 m (approx. 4 minutes) Refraction: retinoscopy and subjective, at 4m (approx. 10 minutes) Anterior eye examination (approx. 4 minutes) 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) Corneal topography measurement with an Oculus Pentacam (Oculus Gmbh., Germany). (approx. 5 minutes) Two measurements of visual acuity will be made: Standard ETDRS logMAR acuity measurement (5 minutes) Vanishing Optotype logMAR acuity measurement (5 minutes)	Device: Moorfields Acuity Chart

Arm

Intervention/Treatment

Experimental: Keratoconic subjects

Short clinical interview (Questions pertaining to ocular and systemic health, medications, family history and date of birth). (approx. 2 minutes) Visual acuity measurement using EDTRS chart at 4 m (approx. 4 minutes) Refraction: retinoscopy and subjective, at 4m (approx. 10 minutes) Anterior eye examination (approx. 4 minutes) 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) Corneal topography measurement with an Oculus Pentacam (Oculus Gmbh., Germany). (approx. 5 minutes) Two measurements of visual acuity will be made: Standard ETDRS logMAR acuity measurement (5 minutes) Vanishing Optotype logMAR acuity measurement (5 minutes)

Device: Moorfields Acuity Chart

Experimental: Healthy subjects

Device: Moorfields Acuity Chart

Outcome Measures

Primary Outcome Measures

The relative difference in visual acuity measurement between subjects with and without keratoconus when examined with different types of visual acuity chart. [9 months]

Secondary Outcome Measures

The relationship (if any) between optical imperfections (high order aberrations) and measurements of visual acuity when measured using different test chart designs. [9 months]

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 35 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

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.

Contacts and Locations

Locations

No locations specified.

Sponsors and Collaborators

Moorfields Eye Hospital NHS Foundation Trust

Investigators

None specified.

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

Responsible Party:

Moorfields Eye Hospital NHS Foundation Trust

ClinicalTrials.gov Identifier:

NCT02429609

Other Study ID Numbers:

ANDO1009

First Posted:

Apr 29, 2015

Last Update Posted:

Apr 12, 2022

Last Verified:

Apr 1, 2022

Additional relevant MeSH terms:

Keratoconus

Study Results

No Results Posted as of Apr 12, 2022