Exploring the Psychophysics of Keratoconus Using the Moorfields Acuity Chart

Keratoconic Subjects Clinical Trial

— MACK  

Official title:

Exploring the Psychophysics of Keratoconus Using the Moorfields Acuity Chart

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02429609
• Other study ID #: ANDO1009
• Status: Completed
• Phase: N/A
• Start date: April 15, 2015
• Est. completion date: April 30, 2016

Study information

• Verified date: April 2022
• Source: Moorfields Eye Hospital NHS Foundation Trust
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 80
• Est. completion date: April 30, 2016
• Est. primary completion date: April 30, 2016
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 35 Years

Eligibility

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.

Related Conditions & MeSH terms

• Keratoconic Subjects
• Keratoconus

Intervention

Device:
• Moorfields Acuity Chart

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
Moorfields Eye Hospital NHS Foundation Trust

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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	The relationship (if any) between optical imperfections (high order aberrations) and measurements of visual acuity when measured using different test chart designs.		9 months