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A way to clean soft contact lenses without the detergents that can irritate
eyes is being developed from a method used to transfer proteins in laboratory
studies. Å®ÉúСÊÓƵs at North Carolina State University say that the technique,
called electro-blotting, cleans lenses thoroughly using just a trickle of
electric current, blotting paper and saline solution.

‘This process may enable people who are allergic or sensitive to cleaning
agents to wear contacts,’ says Harold Swaisgood, professor of food science
and biochemistry at NCSU.

Electro-blotting was developed to transfer proteins from a porous gel
onto blotting paper. Protein molecules carry an electrical charge, either
positive or negative, so in the presence of an electric field the molecule
moves with a mobility proportional to the size of its charge. For cleaning
lenses, which become coated with proteins from the wearer’s tears, electro-blotting
causes proteins to migrate from the lens into wet blotting paper placed
over both sides of the lens. ‘In just four hours, almost all the deposits
on a lens have migrated onto the paper, which is then discarded,’ says Swaisgood.

Marie Walsh, a member of the NCSU team, says: ‘Electro-blotting removed
94.42 per cent of the protein. Hand-washing with a commercial cleaner removed
86.87 per cent.’ For anyone allergic to the detergent, electro-blotting
would be a useful alternative.

Salem Products Development of Winston-Salem in North Carolina, is testing
a prototype lens-cleaning device. The final kit could be on sale within
three years and cost less than $100.