A New Parameter for the Assessment of Distance Visual Capacity: the Critical Visual Acuity (CVA)

NCT04632901 | Active Not Recruiting DMC

• 1 other identifier: ES12/Th3/17-9-2020
• Study Type: observational
• Target: 300
• Locations: 1 country
• Sites: 1

Brief Summary

The conventional examination of the visual acuity (VA) does not take into account the patient's reading speed. However, the consideration of the speed for the recognition of the VA charts' symbols leads to the more accurate and comprehensive assessment of the visual capacity. Therefore, primary objective of this study is to develop and validate a new parameter for the more comprehensive evaluation of visual capacity: the critical visual acuity (CVA). CVA takes into account the speed of recognition of the symbols of the distance visual charts.

Conditions

Visual Acuity

Keywords

maximum reading speed; critical visual acuity; visual capacity

Outcome Measures

Primary Outcomes (2)

• Critical Visual Acuity (CVA)

  The smallest line (measured in letters) that can be read with the maximum reading speed, i.e., with speed greater than or equal to the average reading speed of the larger lines minus 1.96 times the standard deviation (SD) of the reading speed of these lines. In clinical practice, the CVA is the minimum VA that can be read in maximal speed.

  6 months

• Visual Acuity (VA)

  The smallest line (measured in letters) that can be read with speed greater than or equal to the average reading speed of the larger lines minus 2.58 times the standard deviation (SD) of the reading speed of these lines. In clinical practice, the VA is the common parameter of VA adding a tolerant time limit to clearly determine the end of the test.

  6 months

Secondary Outcomes (1)

• Intraclass Correlation Coefficients (ICCs) for study participants

  through study completion, an average of 3 months

Other Outcomes (1)

• Test-retest Intraclass Correlation Coefficients (ICCs)

  through study completion, an average of 3 months

Study Arms (2)

Testing of Visual Acuity (VA) Group

The same participants will undergo VA and CVA test with two different Landolt C charts under the same lighting conditions.

Diagnostic Test: VA assessment

Testing of Critical Visual Acuity (CVA) Group

The same participants will undergo VA and CVA test with two different Landolt C charts under the same lighting conditions.

Diagnostic Test: CVA assessment

Interventions

VA assessment DIAGNOSTIC_TEST

The VA of all participants will be evaluated by counting the smallest line that can be read within a time duration greater than or equal to the average reading time of the larger lines minus 2.58 times the SD of the reading time of these lines. In clinical practice, the VA is the common parameter of VA adding a tolerant time limit to clearly determine the end of the test.

Testing of Visual Acuity (VA) Group

CVA assessment DIAGNOSTIC_TEST

The CVA of all participants will be evaluated by counting the smallest line that can be read within a time duration greater than or equal to the average reading time of the larger lines minus 1.96 times the SD of the reading time of these lines. In clinical practice, the CVA is the minimum VA that can be read in maximal speed.

Testing of Critical Visual Acuity (CVA) Group

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Probability Sample

Study Population

300 patients who will come to the outpatient clinics of the Ophthalmology Department of the University Hospital of Alexandroupolis, aged 18-75 years, will be examined.

You may qualify if:

• People aged 18 - 75 years

You may not qualify if:

• neurological diseases
• mental diseases
• mental retardation,
• difficulty reading
• previous intraocular surgery

Sponsors & Collaborators

• Democritus University of Thrace: lead

Study Sites (1)

Department of Ophthalmology, University Hospital of Alexandroupolis

Alexandroupoli, Evros, 68100, Greece

Location

Study Officials

• Georgios Labiris, MD, PhD

  Department of Ophthalmology, University Hospital of Alexandroupolis, Alexandroupolis, Greece

  STUDY CHAIR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 15 Days
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor (Associate) of Democritus University of Thrace

Study Record Dates

• First Submitted: November 12, 2020
• First Posted: November 17, 2020
• Study Start: September 20, 2020
• Primary Completion: July 20, 2025
• Study Completion: December 20, 2025
• Last Updated: July 11, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will not share

Locations

GR (1)