Extended wear contact lens movement under swimming pool conditions.

On site swimming pool studies have indicated that soft contact lenses adhere to the cornea when exposed to swimming pool water. It was the aim of this investigation to study, under controlled laboratory conditions, both the adherence of hydrophilic extended wear lenses and any changes in lens movement with exposure to swimming pool water. Normal saline and a hypotonic solution having a pH and osmolality identical to the pool water served as controls. Exposure to both swimming pool water and the hypotonic solution promptly caused both lenses to stop moving and adhere to the cornea. Notably, the instillation of normal saline also caused a dramatic decrease in lens movement for some subjects.