Frequency 55 Toric contact lenses are an excellent contact lens option for those who have astigmatism. For many that have this condition, also known as a non-symmetrical cornea, finding contact lenses that are comfortable and effectively correct their eyesight can be a challenge. The Frequency 55 Toric lenses are 30-day disposable lenses that can be used for daily wear, but can also be worn for an extended period of up to seven days – though the lenses must be removed, cleaned and disinfected at least once during this time period. After 30 days, simply toss the old lenses out and replace them with a new pair. The amount of time these lenses can be worn should be determined between you and your eye care provider.