Following cataract surgery, an intraocular lens (IOL) is implanted in the eye. The majority of people develop an operable cataract when they are over the age of 50. Occasionally people under 50 years develop a cataract requiring an operation. The visual demands in this age group are very different due to both physiological and lifestyle factors. Traditionally IOLs are focussed for distance vision and additional spectacles are worn for near vision. Under the age of 45 years we have the ability to naturally change the focus of our eyes and do not require additional reading glasses. This is known as accommodation. By removing the cataractous lens and replacing it with an IOL with a fixed single focus, both eyes work together for distance vision but only the unoperated eye is able to change focus for different working distances. This study aims to establish whether a multifocal IOL implanted in one eye is able to complement the accommodation in the other eye so the 2 eyes work more effectively together. This may enhance depth perception and improve the quality of vision. Depth perception is important for more comfortable vision on the computer screen, when reading and for jobs that require good depth perception.