Vision screen boards
The earlier ametropia is recognized, the better.
For this purpose, eye charts with various visual signs (optotypes) are available to determine visual acuity.
In addition to letters and numbers, the standardized Landolt rings, E-hooks (Snellen) and LEA symbols have gained most acceptance.
The Ishihara, Matsubara or Color DX color tests can be used to determine congenital color vision disorders.
There are different test versions available for children, adults and illiterates.
An early squint or micro-strabismus can easily be detected with the stereotest Lang I or Lang II.