The present research process is a prospective, non-interventional clinical study that will be conducted -under the auspices of the Democritus University of Thrace (DUTH)- in the pre-school students of the city of Alexandroupolis, Greece.

• The study aims to assess the visual acuity of the kindergarten students.
• The measurement of monocular best-spectacle corrected visual acuity will be performed using a web-based visual acuity chart

Study protocol will adhere to the tenets of the Declaration of Helsinki and written informed consent will be obtained by the legal guardians of all participants.

The measurement of the visual acuity (monocular and binocular) will be performed using DDART, a digital visual acuity tool that has been developed and validated by the Democritus University of Thrace and is also an approved Category 1 Medical Device by the country's National Organization for Medicines, via a web-based digital chart in a high-resolution screen. The same environmental lighting conditions and the same screen brightness will be applied. The examination will be performed at the same predetermined viewing distance.

Finally, according to each participant's visual acuity, appropriate instructions will be given for further examinations directly to the legal guardians in order to comply with the GDPR.

Inclusion Criteria:

• Pre-school students aged 5-7 years old.

Exclusion Criteria:

• Age >7 years old
• Students with health conditions that do not allow the evaluation of the visual acuity .

Pre-school students aged 5-7 years old