Estonian regulations allowed spectacles etc to be used in deciding whether prison guards met vision requirements, but did not allow hearing aids in assessing their hearing. The EU court held this hearing requirement was not likely to be justified.
More generally, the regulations did not allow consideration of reasonable adjustments.
The regulations therefore appeared to impose a hearing requirement going beyond what was necessary to attain its objectives.
As a post-Brexit EU Court decision, it is not binding on UK courts but they may take it into account if they consider appropriate.
The case is XX v Tartu Vangla, EU Court of Justice, 2021 eur-lex.europa.eu