Validation of DDIVAT Digital Optotypes for Distance Visual Acuity Testing Among the Bulgarian Population

NCT07208838 | Enrolling By Invitation

• 1 other identifier: PlovdivMUDDIVAT
• Study Type: observational
• Target: 150
• Locations: 1 country
• Sites: 1

Brief 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 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

Outcome Measures

Primary Outcomes (1)

• The study is expected to prove that the distance visual acuity of patients examined by both methods is identical.

  12 monts

Study Arms (1)

Healthy participants

75 males and 75 females over 18 years of age

Diagnostic Test: To test visual acuity in 150 Bulgarian patients over 18 years of age using Snellens visual acuity chart and DDIVAT optotypes

Interventions

To test visual acuity in 150 Bulgarian patients over 18 years of age using Snellens visual acuity chart and DDIVAT optotypes DIAGNOSTIC_TEST

The study compares newly developed visual acuity test (DDIVAT) with standart method for visual acuity testing used worldwide

Healthy participants

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

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.

You may qualify if:

• 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.

You may not qualify if:

• Patients of less than 18 years of age.

Sponsors & Collaborators

• Plovdiv Medical University: lead
• Democritus University of Thrace: collaborator

Study Sites (1)

Medical University Plovdiv

Plovdiv, 4004, Bulgaria

Location

Related Publications (4)

• 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.

  PMID: 39963735 BACKGROUND

• Labiris 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.

  PMID: 34588763 BACKGROUND

• Labiris 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.

  PMID: 33102611 BACKGROUND

• Labiris 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.

  PMID: 36853857 BACKGROUND

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 1 Day
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: MD, PhD

Study Record Dates

• First Submitted: September 28, 2025
• First Posted: October 6, 2025
• Study Start: October 1, 2025
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): July 1, 2026
• Last Updated: October 6, 2025

Record last verified: 2025-04

Data Sharing

• IPD Sharing: Will share

Locations

BU (1)