Visual AcuityNCT07240480
Assessing the Turkish DDIVAT for Visual Acuity Measurement
An observational study of Visual Acuity and Refractive Errors, run by Trakya University.
Trial 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… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Visual Acuity, Refractive Errors, Myopia
- What is being tested?
- DDIVAT Visual Acuity Test (Turkish Version)
- How many people
- 200 participants
- Where
- No sites listed yet
- Study dates
- 1 Dec 2025to 31 May 2026
- How long will I take part?
- 1 Day
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
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).
Who may be able to join
- 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)
Who cannot join
- 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
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Validation of the Turkish Version of the DDIVAT Visual Acuity Measuring Device in a Turkish-speaking Population
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:
Read more
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.
Read the 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.
- Conditions
- Visual Acuity, Refractive Errors, Myopia, Hyperopia, Astigmatism
- Being tested
- DDIVAT Visual Acuity Test (Turkish Version)
- Keywords
- Visual Acuity, Refractive Errors
- Medical subject headings
- Refractive Errors, Myopia, Hyperopia, Astigmatism
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
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.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: Diagnostic Test: DDIVAT Visual Acuity Test (Turkish Version) |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: During a single study visit (same day assessment)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Nov 2025
- Study start1 Dec 2025 (estimated)
- Primary completion30 Apr 2026 (estimated)
- Study completion31 May 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Visual AcuityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 200 participants (estimated)
- Target duration
- 1 Day
Sponsor and investigators
- Lead sponsor
- Trakya University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Prof. Dr. Hande Guclu, Trakya University
- Investigators
- Hande Güçlü, M.D., Prof. Dr., Principal investigator, Trakya University Faculty of Medicine Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07240480
- Sponsor's protocol ID
- Turkish DDIVAT TrakyaUni
- Status last verified
- Oct 2025
- First submitted
- 16 Nov 2025
- Last updated
- 4 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- Individual data sharing
- No: This is a minimal-risk, non-interventional validation study conducted at a single institution. The collected data will be anonymized and analyzed internally. Individual participant-level data will not be shared outside Trakya University Faculty of Medicine due to institutional data-protection policies.
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.
PubMed 35110066Daiber 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/
PubMed 33085445
Study at a glance
From the registry record, last updated by the sponsor on 4 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Validation of the Turkish Version of the DDIVAT Visual Acuity Measuring Device in a Turkish-speaking Population
- ClinicalTrials.gov ID
- NCT07240480
- Acronym / sponsor ID
- Turkish DDIVAT TrakyaUni
- Conditions
- Visual Acuity, Refractive Errors, Myopia, Hyperopia, Astigmatism
- Keywords
- Visual Acuity, Refractive Errors
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Trakya UniversityUniversity, hospital or other
- Study start
- 1 Dec 2025 (estimated)
- Primary completion
- 30 Apr 2026 (estimated)
- Study completion
- 31 May 2026 (estimated)
- First posted
- 21 Nov 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 1 Day
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Participants Undergoing Visual Acuity Testing | – | Diagnostic Test: DDIVAT Visual Acuity Test (Turkish Version)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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- 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).
Key inclusion criteria (4 listed)
- 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)
Key exclusion criteria (4 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 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. | Diagnostic test | Participants Undergoing Visual Acuity Testing |
Primary outcome
Agreement between DDIVAT (Turkish version) and Snellen chart visual acuity measurements
Time frame: During a single study visit (same day assessment)
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.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Dec 2025.
- Background: PubMed 35110066Posar 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.
- Background: PubMed 33085445Daiber 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/
- Individual participant dataSharing planned: No. This is a minimal-risk, non-interventional validation study conducted at a single institution. The collected data will be anonymized and analyzed internally. Individual participant-level data will not be shared outside Trakya University Faculty of Medicine due to institutional data-protection policies.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Hande Güçlü, M.D., Prof. Dr. principal investigator
Trakya University Faculty of Medicine Hospital
Questions about this trial
What is this clinical trial studying?
An observational study of Visual Acuity and Refractive Errors, run by Trakya University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 4 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Tuğçe Bek, M.D. (+90 533 560 2583, tugcebek@trakya.edu.tr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Agreement between DDIVAT (Turkish version) and Snellen chart visual acuity measurements (time frame: During a single study visit (same day assessment)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07240480, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Dec 2025; AzTrials last refreshed its copy on 26 Oct 2026.