The use of contact lenses in wet or damp environments

The adhesion between the eye and a contact lens was recorded when influenced by water with varying salt concentrations. Both active removal and spontaneous loss of hard and soft contact lenses applied to the eye were investigated. In environments with saline less than 9 0/00 the risk of a soft contact lens falling out from the eye is almost negligible. In environments with saline greater than or equal to 9 0/00 the risk increase since adhesion in active removal decreased considerably. In reality, based upon the investigations of spontaneous loss of contact lenses in an underwater environment, well fitted soft lenses still do not however fall out of the eye. It should therefore be possible to use well fitted soft contact lenses without any significant risk even in working conditions which may include splashing of water upon the eye and regardless of the various salt concentrations of naturally occurring water in Sweden. For hard contact lenses, independent of salt concentration, adhesion in the underwater environment is extremely low and such lenses cannot therefore be used on an unprotected eye in conjunction with, for example, swimming. The risk of them falling out under splashing with water upon the eye is clearly greater than for soft lenses.