Hydrogel Contact Lens Dehydration in Controlled Environmental Conditions

PURPOSE: To ascertain the impact of environmental conditions on hydrogel contact lens dehydration. METHODS: Six young adult subjects wore an ACUVUE lens in one eye and a Proclear lens in the other eye for 200 minute sessions in arid, temperate, and arctic conditions, maintained in a purpose-built environmental chamber in an aerospace medical facility. Dehydration was determined by measuring lens water content before and after each session using a soft contact lens refractometer. Comfort of the lenses was assessed at the conclusion of each session. RESULTS: Lens dehydration was similar for the three environmental conditions (F2 = 0.3, P = 0.75). There was less dehydration with the Proclear lens compared with ACUVUE lens (F1 = 43.0, P = 0.001). No differences were detected with respect to lens comfort between the three environmental conditions (F2 = 2.0, P = 0.18) or the two lens types (F1 = 1.4, P = 0.29). CONCLUSION: Soft contact lens dehydration is unaffected by environmental extremes.