Patients who are over 40 years old develop "presbyopia", which is an inability to focus at things up close due to changes of the lens inside the eye. Since patients with presbyopia often are nearsighted or farsighted as well, contact lenses have been designed to correct both for distance and near vision. They are called bifocal or multifocal contact lenses, depending on the design.
Many designs of bifocal and multifocal contact lenses are available today. The multifocal contact lens options have expanded to include many different designs and most prescriptions. Multifocal contact lenses are available in soft and firm materials. There are many different multifocal designs and each design has different ways of enabling the wearer to see at all distances.
Fitting multifocal contact lenses is a process that involves the patient and doctor working as a team to get the best possible vision for most tasks. All multifocals require an adaptation period as the brain adapts to a different way of seeing with the contact lenses on. This can be as short as one day to as long as two weeks.
For patients who cannot adapt to a multifocal contact lens, monovision is an option. In a monovision fit, one eye is corrected to see well at distance and the other is used to see up close. As with multifocal contact lenses, there is an adaptation process with monovision as the brain gets used to "seeing" in this new way. Most people are able to adapt to monovision in a few days to a week. Some people may experience slightly diminished depth perception and may need to alternate between their contact lenses during the day and a pair of conventionally fitted contact lenses or eyeglasses for certain tasks, like driving at night.