Little risk posed by 30-day CLs

Researchers have found the corneal infection rate of patients using 30-day extended wear silicone hydrogel contact lenses is comparable to that previously reported for older lens types worn for fewer consecutive 24-hour periods.

The research team, from US-based Johns Hopkins Wilmer Eye Institute, recruited 6,245 patients who were fitted with CIBA Vision Night & Day silicone hydrogel soft contact lenses, to be worn for 30 consecutive 24-hour periods.

Four out of five participants completed 12 months' wear and wore their lenses for three or more weeks continuously.

The overall annual rate of evident corneal infection was 18 per 10,000.
There were two cases of corneal infection with partial loss of vision, and an additional eight cases without vision loss.

The rate of infection was lower for users wearing lenses for three or more weeks than for those wearing lenses for less than three-week continuous periods.

'Daily wear rigid gas-permeable contact lenses appear to have the lowest risk for corneal infection,' said Oliver Schein, lead investigator of the study, 'followed by daily wear soft contact lenses and seven- or 30-day-wear soft contact lenses.

'Not everyone can wear the lenses successfully for a full 30-nights, but the risk of infection does not appear to increase with a greater number of consecutive nights of wear. This is a different pattern than we previously observed.'