Role of hypo-osmotic saline drops in ocular comfort during contact lens wear☆
published online 01 February 2010.
Abstract
Purpose
To determine whether hypo-osmotic saline drops can improve contact lens associated discomfort and dryness by decreasing contact lens osmolality.
Methods
Fifteen symptomatic subjects wore Lotrafilcon A lenses bilaterally for 6h on two different days. According to randomisation, hypo-osmotic (280mmol/kg) or hyper-osmotic (380mmol/kg) saline drops were applied four times during each day and ocular symptoms, tear film and contact lens parameters, and contact lens osmolality were assessed.
Results
Sixty percent of the subjects preferred the hypo-osmotic saline drops, compared to 33%, who preferred the hyper-osmotic ones. Subjects experienced significantly less dryness and lens awareness with hypo-osmotic saline drops compared to hyper-osmotic ones (p<0.05). Using the hypo-osmotic drops, there was a trend for decreased contact lens osmolality from 379 to 343mmol/kg (p=0.06). There were no differences in lipid layer, non-invasive tear film break-up time, lens surface wettability, lens water content after wear, lens movement on eye or ocular staining and indentation between saline drops (all p>0.05). Interestingly, the difference in contact lens osmolality between drops did not reflect the osmolality difference between the two saline drops.
Conclusion
Hypo-osmotic saline drops were preferred by a greater number of subjects and contact lens osmolality tended to be lower with the use of hypo-osmotic saline. Hypo-osmotic drops have the potential to decrease contact lens osmolality which in turn may help improve ocular comfort. This has possible impact on the practitioners’ choice of the lens rewetting drop recommended and the design of future lens rewetting drops.
aThe Vision Cooperative Research Centre, Sydney, Australia
bThe Institute for Eye Research, Sydney, Australia
cSchool of Optometry and Vision Science, University of New South Wales, Sydney, Australia
Corresponding author at: School of Optometry and Vision Science, Level 3, Rupert Myers Building, North Wing, Gate 14, Barker Street, NSW, 2052, Australia. Tel.: +61 2 9385 4624; fax: +61 2 9313 6243.
☆ This study was supported in part by the Australian Government through the Cooperative Research Centres Scheme, an International Postgraduate Research Scholarship through the University of New South Wales and by the Contact Lens Society of Australia Research Award (US).
ABSTRACT