You should always wear approved Eyewear when playing Squash:-
Protective eyewear is recommended by Squash Australia. The World Squash Federation displays a listing of eyewear that satisfies national product testing across a number of jurisdictions. The listing is available from the WSF website. http://www.worldsquash.org.uk/jun-eye.asp Squash Australia's Regulation relevant to Eyewear is Regulation 42:
Safety
Quote from Squash Australia