Assessing the Turkish DDIVAT for Visual Acuity Measurement
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In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: DDIVAT Visual Acuity Test (Turkish Version).
- Who it may be relevant to
- Registry conditions: Visual Acuity, Refractive Errors, Myopia, Hyperopia. Basic parameters: from 18 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Center list to be confirmed — check the primary protocol.
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
Validation of the Turkish Version of the DDIVAT Visual Acuity Measuring Device in a Turkish-speaking Population
Overview
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.
Detailed description
This study is a non-interventional, observational methodological validation study designed to evaluate the validity and reliability of the Turkish version of the DDIVAT (Digital Distance Interactive Visual Acuity Test) in a Turkish-speaking population.
The DDIVAT visual acuity test was originally developed and validated at Democritus University of Thrace (Greece) and has been approved by the National Medicines Organization as a Class I medical device. The current study aims to determine whether the Turkish-translated version of this visual acuity measurement tool performs consistently and accurately among Turkish-speaking participants.
Visual acuity is one of the most fundamental components of a comprehensive ophthalmological examination. It measures the clarity or sharpness of vision, which can be influenced by refractive errors and a variety of ocular diseases. Accurate and accessible tools for measuring visual acuity are therefore essential in both clinical and research settings.
In this study, 200 adult participants (aged 18 years and older) will be recruited from Trakya University Hospital, Department of Ophthalmology (Edirne, Türkiye). The study population will include both healthy volunteers and patients presenting to the ophthalmology clinic.
Each participant will undergo two visual acuity measurements under standardized conditions:
DDIVAT visual acuity test (Turkish version), administered via a smart TV connected to the university's secure server.
Snellen chart test, which represents the standard clinical practice currently used at Trakya University Hospital.
Measurements will be taken monocularly (each eye tested separately) while participants wear their current optical correction (e.g., eyeglasses or contact lenses).
The study will compare the two measurement methods to determine:
The level of agreement between DDIVAT and Snellen test results.
The test-retest reliability of the Turkish DDIVAT.
Since no medication, invasive procedure, or experimental intervention will be applied, the study poses no potential risk to participants. All procedures will comply with the Declaration of Helsinki, Good Clinical Practice (GCP) principles, and relevant data protection regulations.
Collected data will be stored anonymously and used solely for research purposes. The findings are expected to provide evidence supporting the use of DDIVAT as a reliable digital visual acuity tool for Turkish-speaking populations, enhancing accessibility and standardization of visual testing in both clinical and teleophthalmology contexts.
Interventions
- Diagnostic test DDIVAT Visual Acuity Test (Turkish Version)
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.
Primary outcome measures
- Agreement between DDIVAT (Turkish version) and Snellen chart visual acuity measurements [Time frame: During a single study visit (same day assessment)]
Eligibility criteria
Inclusion criteria
- 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)
Exclusion criteria
- 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
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Observational model
- Cohort
Study locations
Center list to be confirmed — check the primary protocol.
Publications
- 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
- Daiber HF, Gnugnoli DM. Visual Acuity(Archived). 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
Identifiers
NCT: NCT07240480 · Turkish DDIVAT TrakyaUni