Vision ScreeningNCT07208838
Validation of DDIVAT Digital Optotypes for Distance Visual Acuity Testing Among the Bulgarian Population
An observational study of Vision Screening, run by Plovdiv Medical University at 1 site in Bulgaria.
Trial summary
To compare distance visual acuity in Bulgarian patients over 18 years of age using two different methods - the Snellen method and the DIDIVAT digital online optotypes. For the purpose of this study, it is planned to examine native visual acuity (with and without prescribed optical correction), without additional… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Vision Screening
- What is being tested?
- To test visual acuity in 150 Bulgarian patients over 18 years of age using Snellens visual acuity chart and DDIVAT optotypes
- How many people
- 150 participants
- Where
- 1 siteBulgaria
- Study dates
- 1 Oct 2025to 1 Jul 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: Bulgarian speaking patients (75 women and 75 men) over 18 years of age, hospitalized in a university eye clinic at St. George University Hospital and healthy volunteers willing to participate in the study.
Who may be able to join
- Bulgarian speaking patients (75 women and 75 men) over 18 years of age, hospitalized in a university eye clinic at St. George University Hospital and healthy volunteers willing to participate in the study.
Who cannot join
- Patients of less than 18 years of age.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
About this study
To compare distance visual acuity in Bulgarian patients over 18 years of age using two different methods - the Snellen method and the DIDIVAT digital online optotypes. For the purpose of this study, it is planned to examine native visual acuity (with and without prescribed optical correction), without additional mydriasis in both ways, of 150 Bulgarian patients (75 women and 75 men) over 18 years of age, hospitalized in a university eye clinic at St. George University Hospital and healthy volunteers willing to participate in the study. The statistical analysis that will be performed will aim to compare whether the two methods for determining distance visual acuity are identical in results, as well as to validate the application for the Bulgarian population.The study is expected to prove that the distance visual acuity of patients examined by both methods is identical.
- Conditions
- Vision Screening
- Being tested
- To test visual acuity in 150 Bulgarian patients over 18 years of age using Snellens visual acuity chart and DDIVAT optotypes
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
To test visual acuity in 150 Bulgarian patients over 18 years of age using Snellens visual acuity chart and DDIVAT optotypesDiagnostic test
The study compares newly developed visual acuity test (DDIVAT) with standart method for visual acuity testing used worldwide
| Study group | Role | What they receive |
|---|---|---|
| Healthy participants | 75 males and 75 females over 18 years of age Receives: Diagnostic Test: To test visual acuity in 150 Bulgarian patients over 18 years of age using Snellens visual acuity chart and DDIVAT optotypes |
What is being measured
The primary outcome is the main question the study is designed to answer.
The study is expected to prove that the distance visual acuity of patients examined by both methods is identical.
Measured: 12 monts
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Oct 2025
- Study start1 Oct 2025 (estimated)
- Primary completion1 Jul 2026 (estimated)
- Study completion1 Jul 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Vision ScreeningStudies 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
- 150 participants (estimated)
- Target duration
- 1 Day
Sponsor and investigators
- Lead sponsor
- Plovdiv Medical University
- Sponsor type
- University, hospital or other
- Collaborators
- Democritus University of Thrace
- Responsible party
- Principal investigator, Vasil Marinov, Plovdiv Medical University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07208838
- Sponsor's protocol ID
- PlovdivMUDDIVAT
- Status last verified
- Apr 2025
- First submitted
- 28 Sep 2025
- Last updated
- 6 Oct 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes
Publications
Bakirtzis M, Michaleakou E, Martidou ME, Lahana E, Kostagiolas P, Niakas D, Labiris G. Visual Acuity Screening of Refugees and Immigrants with a Web-Based Digital Test: A Pilot Study. Acta Medica (Hradec Kralove). 2024;67(3):79-86. doi: 10.14712/18059694.2025.2.
PubMed 39963735Labiris G, Panagiotopoulou EK, Duzha E, Tzinava M, Perente A, Konstantinidis A, Delibasis K. Development and Validation of a Web-Based Reading Test for Normal and Low Vision Patients. Clin Ophthalmol. 2021 Sep 22;15:3915-3929. doi: 10.2147/OPTH.S314943. eCollection 2021.
PubMed 34588763Labiris G, Panagiotopoulou EK, Chatzimichael E, Tzinava M, Mataftsi A, Delibasis K. Introduction of a digital near-vision reading test for normal and low vision adults: development and validation. Eye Vis (Lond). 2020 Oct 22;7:51. doi: 10.1186/s40662-020-00216-0. eCollection 2020.
PubMed 33102611Labiris G, Panagiotopoulou EK, Delibasis K, Duzha E, Bakirtzis M, Panagis C, Boboridis K, Mokka A, Balidis M, Damtsi C, Ntonti P. Validation of a web-based distance visual acuity test. J Cataract Refract Surg. 2023 Jul 1;49(7):666-671. doi: 10.1097/j.jcrs.0000000000001176.
PubMed 36853857
Study at a glance
From the registry record, last updated by the sponsor on 6 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Validation of DDIVAT Digital Optotypes for Distance Visual Acuity Testing Among the Bulgarian Population
- ClinicalTrials.gov ID
- NCT07208838
- Acronym / sponsor ID
- PlovdivMUDDIVAT
- Conditions
- Vision Screening
- Study type
- Observational
- Recruitment status
- Enrolling by invitation
- Enrolment
- 150 participants (estimated)
- Lead sponsor
- Plovdiv Medical UniversityUniversity, hospital or other
- Collaborators
- Democritus University of Thrace
- Study start
- 1 Oct 2025 (estimated)
- Primary completion
- 1 Jul 2026 (estimated)
- Study completion
- 1 Jul 2026 (estimated)
- First posted
- 6 Oct 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.
To compare distance visual acuity in Bulgarian patients over 18 years of age using two different methods - the Snellen method and the DIDIVAT digital online optotypes. For the purpose of this study, it is planned to examine native visual acuity (with and without prescribed optical correction), without additional mydriasis in both ways, of 150 Bulgarian patients (75 women and 75 men) over 18 years of age, hospitalized in a university eye clinic at St. George University Hospital and healthy volunteers willing to participate in the study. The statistical analysis that will be performed will aim to compare whether the two methods for determining distance visual acuity are identical in results, as well as to validate the application for the Bulgarian population.The study is expected to prove that the distance visual acuity of patients examined by both methods is identical.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 1 Day
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Healthy participants | – | Diagnostic Test: To test visual acuity in 150 Bulgarian patients over 18 years of age using Snellens visual acuity chart and DDIVAT optotypes75 males and 75 females over 18 years of age |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Bulgarian speaking patients (75 women and 75 men) over 18 years of age, hospitalized in a university eye clinic at St. George University Hospital and healthy volunteers willing to participate in the study.
Key inclusion criteria (1 listed)
- Bulgarian speaking patients (75 women and 75 men) over 18 years of age, hospitalized in a university eye clinic at St. George University Hospital and healthy volunteers willing to participate in the study.
Key exclusion criteria (1 listed)
- Patients of less than 18 years of age.
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 |
|---|---|---|
| To test visual acuity in 150 Bulgarian patients over 18 years of age using Snellens visual acuity chart and DDIVAT optotypesThe study compares newly developed visual acuity test (DDIVAT) with standart method for visual acuity testing used worldwide | Diagnostic test | Healthy participants |
Primary outcome
The study is expected to prove that the distance visual acuity of patients examined by both methods is identical.
Time frame: 12 monts
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 6 Oct 2025.
- Background: PubMed 39963735Bakirtzis M, Michaleakou E, Martidou ME, Lahana E, Kostagiolas P, Niakas D, Labiris G. Visual Acuity Screening of Refugees and Immigrants with a Web-Based Digital Test: A Pilot Study. Acta Medica (Hradec Kralove). 2024;67(3):79-86. doi: 10.14712/18059694.2025.2.
- Background: PubMed 34588763Labiris G, Panagiotopoulou EK, Duzha E, Tzinava M, Perente A, Konstantinidis A, Delibasis K. Development and Validation of a Web-Based Reading Test for Normal and Low Vision Patients. Clin Ophthalmol. 2021 Sep 22;15:3915-3929. doi: 10.2147/OPTH.S314943. eCollection 2021.
- Background: PubMed 33102611Labiris G, Panagiotopoulou EK, Chatzimichael E, Tzinava M, Mataftsi A, Delibasis K. Introduction of a digital near-vision reading test for normal and low vision adults: development and validation. Eye Vis (Lond). 2020 Oct 22;7:51. doi: 10.1186/s40662-020-00216-0. eCollection 2020.
- Background: PubMed 36853857Labiris G, Panagiotopoulou EK, Delibasis K, Duzha E, Bakirtzis M, Panagis C, Boboridis K, Mokka A, Balidis M, Damtsi C, Ntonti P. Validation of a web-based distance visual acuity test. J Cataract Refract Surg. 2023 Jul 1;49(7):666-671. doi: 10.1097/j.jcrs.0000000000001176.
- Individual participant dataSharing planned: Yes
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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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Vision Screening, run by Plovdiv Medical University at 1 site in Bulgaria.
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 1 inclusion and 1 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: enrolling by invitation, as of the sponsor's last update on 6 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Bulgaria. Whether a site is taking part right now should be confirmed with that site. See every site.
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?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The study is expected to prove that the distance visual acuity of patients examined by both methods is identical. (time frame: 12 monts). 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 NCT07208838, which also lists 4 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 6 Oct 2025.