Assessing the Turkish DDIVAT for Visual Acuity Measurement

NCT07240480 | Not Yet Recruiting

• 1 other identifier: Turkish DDIVAT TrakyaUni
• Study Type: observational
• Target: 200
• Locations: 0 countries
• Sites: N/A

Brief Summary

The goal of this observational methodological study is to validate the Turkish version of the DDIVAT visual acuity measuring device in a Turkish-speaking adult population. The main questions it aims to answer are: Does the Turkish version of the DDIVAT provide reliable and valid visual acuity measurements in Turkish speakers? Are the results of the DDIVAT comparable to those obtained with the standard Snellen chart used in clinical practice? Researchers will compare DDIVAT visual acuity test results with Snellen chart results to see if both methods produce consistent measurements. Participants will: Be adults aged 18 years or older, including both patients and healthy volunteers. Undergo visual acuity testing using the DDIVAT system displayed on a smart TV connected to the university server. Have their visual acuity re-measured using the standard Snellen optotype under the same conditions. No medication or invasive procedure will be used. The study carries no risk to participants.

Conditions

Visual Acuity; Refractive Errors; Myopia; Hyperopia; Astigmatism

Keywords

Visual Acuity; Refractive Errors

Outcome Measures

Primary Outcomes (1)

• Agreement between DDIVAT (Turkish version) and Snellen chart visual acuity measurements

  The primary outcome is to assess the level of agreement between visual acuity scores obtained using the Turkish version of the DDIVAT digital visual acuity device and those obtained using the standard Snellen chart. Statistical analysis will include correlation and Bland-Altman agreement methods to evaluate consistency and validity between the two testing methods.

  During a single study visit (same day assessment)

Study Arms (1)

Participants Undergoing Visual Acuity Testing

All enrolled participants (n = 200) will complete two visual acuity measurements during a single visit: one using the DDIVAT (Digital Device Independent Visual Acuity Test) Turkish version and one using the standard Snellen chart. The study compares the agreement and test-retest reliability of these two methods. No intervention, medication, or treatment is applied.

Diagnostic Test: DDIVAT Visual Acuity Test (Turkish Version)

Interventions

DDIVAT Visual Acuity Test (Turkish Version) DIAGNOSTIC_TEST

Participants' visual acuity will be measured using the Turkish version of the DDIVAT digital visual acuity device and compared with Snellen chart results. No treatment or invasive procedure will be performed.

Participants Undergoing Visual Acuity Testing

Eligibility Criteria

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

Study Population

Turkish-speaking adults (aged 18 and older), including both healthy volunteers and ophthalmology clinic patients, will be recruited from Trakya University Hospital, Department of Ophthalmology (Edirne, Türkiye).

You may qualify if:

• Adults aged 18 years or older
• Turkish-speaking individuals able to understand the study purpose
• Willingness to participate and provide written informed consent
• Participants with or without refractive errors (e.g., myopia, hyperopia, astigmatism)

You may not qualify if:

• Age below 18 years
• Individuals unable to complete visual acuity testing
• Presence of severe ocular pathology (e.g., corneal opacity, retinal detachment) that prevents accurate measurement
• Cognitive or communication difficulties preventing informed consent

Sponsors & Collaborators

• Trakya University: lead

Related Publications (2)

• Posar A, Visconti P. Early Motor Impairment in Children with Autism Spectrum Disorder. Turk Arch Pediatr. 2021 Nov;56(6):646-647. doi: 10.5152/TurkArchPediatr.2021.21168. No abstract available.

  PMID: 35110066 BACKGROUND

• Daiber HF, Gnugnoli DM. Visual Acuity. 2023 May 29. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from http://www.ncbi.nlm.nih.gov/books/NBK563298/

  PMID: 33085445 BACKGROUND

Related Links

• Official site of the DDIVAT (Digital Device Independent Visual Acuity Test) developed at Democritus University of Thrace, Greece.

MeSH Terms

Conditions

Refractive Errors; Myopia; Hyperopia; Astigmatism

Condition Hierarchy (Ancestors)

Eye Diseases

Study Officials

• Hande Güçlü, M.D., Prof. Dr.

  Trakya University Teaching and Research Hospital

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Tuğçe Bek, M.D.

CONTACT

+90 533 560 2583; tugcebek@trakya.edu.tr

Ahmet Kaan Şimşek, Md.

CONTACT

+90 534 323 3010; akaansimsek@trakya.edu.tr

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 1 Day
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Department Head - Ophthalmology (Trakya Univ.)-Principal Investigator

Study Record Dates

• First Submitted: November 16, 2025
• First Posted: November 21, 2025
• Study Start: December 1, 2025
• Primary Completion: April 30, 2026
• Study Completion: May 31, 2026
• Last Updated: December 4, 2025

Record last verified: 2025-10

Data Sharing

• IPD Sharing: Will not share