Binocular Vision in Monocular Pseudophakia (BVMP)

A Prospective Randomised Controlled Trial to Assess Improved Binocular Visual Function in Young Patients Undergoing Monocular Cataract Surgery With a Bifocal Intraocular Lens.

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.

Change in visual acuity and subjective visual comfort at distance, intermediate and near working distances following IOL implantation.

Inclusion Criteria: Participant is willing and able to give informed consent for participation in the study. Male or female, aged 18 - 45. Cataract operation required in one eye only, either due to the presence of cataract affecting visual function, or in combination with surgery which is likely to cause visually significant cataract. Expected visual improvement in operable eye of at least 6/12. Fellow eye with a VA of at least 6/9. Astigmatism of 1.0D or less. Target of emmetropia in the operated eye. Intact posterior capsule with planned implantation into the capsular bag. IOL power required 10 - 30D. Exclusion Criteria: Pre-existing amblyopia or squint. Significant diabetic retinopathy. Macular off retinal detachment with metamorphopsia or poor visual prognosis. Other macula or ophthalmic pathology affecting macula function resulting in poor visual prognosis. Pregnancy, lactating or planned pregnancy during the study period.