A Web-based Digital Distance Visual Acuity Test

• Conditions: Refractive Errors; Vision Disorders; Low Vision
• Interventions: Diagnostic Test: DDVIT testing; Diagnostic Test: ETDRS testing

• Registration Number: NCT04756596
• Lead Sponsor: Democritus University of Thrace

Brief Summary

Primary objective of this study is the development and validation of a web-based application for the examination of the distance visual acuity of normal- and low-vision patients.

Detailed Description

Present study aims to develop and validate a web-based digital distance visual acuity test (Democritus Distance Vision Test - DDVIT). DDVIT is an application, which will be easily accessed through a simple internet connection. This application will provide the possibility of a simple but reliable examination of patients, establishing a commonly accepted way of measuring the distance visual acuity among rural doctors, general practitioners and ophthalmologists.

Specifically, present study aims to develop a new online distance visual acuity test (DDVIT) according to the standards of the Early Treatment Diabetic Retinopathy Study (ETDRS) test and to evaluate the level of agreement between the two visual acuity tests, as well as the test-retest reliability of the online DDVIT visual acuity test.

The first part of the study is the development of the online visual acuity test (letters, numbers, symbols) including the following smart features:

1. Adjustment of the font size according to the size of the computer screen used for the examination

2. Real time calculation of the patient-screen distance through a face detection system

3. Automatic calculation of the reading time of each line (each logMAR)

4. Entering the number of patient's reading errors for each line

5. Automatic calculation of the visual acuity in the following score units:

* Number of Letters (max 85)

* Visual Acuity Score (max 100)

* logMAR

* Decimal

* Snellen Fraction

The calculation of various reading parameters resulting from the aforementioned features (visual acuity score in different units, reading duration (in sec) and number of errors for each slide (line), patient-screen distance for each slide) will be performed after the end of the examination. Except for the html format, a file in the format of Microsoft Excel and Pdf are also generated.

The second part of this study is the clinical validation of the DDVIT visual acuity test. In this part, the reading acuity measured with the DDVIT and ETDRS test are compared.

All the comparisons will take place in two groups: a) a Normal Vision Group (NVG), and b) a Low Vision Group (LVG) in order to estimate the visual acuity in a population with a wide range of vision.

Study Timeline

• Study Start: 2021-02-01
• Study First Submitted: 2021-02-12
• Study First Submitted QC: 2021-02-12
• Study First Posted: 2021-02-16
• Status Verified: 2021-11
• Last Update Submitted: 2021-11-13
• Last Update Posted: 2021-11-16
• Primary Completion: 2022-05-31
• Study Completion: 2022-06-30

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 300

Inclusion Criteria

• Patients of our outpatient ophthalmology clinic
• Age between 18 to 75 years

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Exclusion Criteria

• Dyslexia
• Attention-deficiency
• Former diagnosis of mental and/or psychiatric diseases
• Inability to cooperate

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Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Study group	DDVIT testing	70 patients with normal vision (NVG) 30 patients with low vision (LVG) These patients will be tested on the DDVIT
Study group	ETDRS testing	70 patients with normal vision (NVG) 30 patients with low vision (LVG) These patients will be tested on the DDVIT

Primary Outcome Measures

Name	Time	Method
Distance visual acuity using DDVIT vision test	4 months	The distance visual acuity of the one randomly selected eye of each participant will be evaluated by the examiner using DDVIT vision test.
Distance visual acuity using ETDRS vision test	4 months	The distance visual acuity of the same eye of each participant will be evaluated by the same examiner using the web-based ETDRS vision test under the same predetermined environmental lighting conditions.

Trial Locations

Locations (2)

Department of Ophthalmology, University Hospital of Alexandroupolis; 🇬🇷 Alexandroupolis, Evros, Greece

Department of Computer Science and Biomedical Informatics, University of Thessaly; 🇬🇷 Lamía, Thessaly, Greece