There are many styles of intraocular lenses now available with the aim of decreasing spectacle dependence for both distance and near after cataract surgery. The technology has improved significantly over the last ten years but the the principle behind all multifocal lenses is that light rays are split between a near and distance focus point (and occasionally an intermediate point as well). The latest versions of these lenses are very efficient at splitting the light energy but the amount of light available at either the distance or near point is inevitably reduced by over 50%. Healthy eyes can cope very well with this reduced light intensity but if there is any additional eye problem (eg: glaucoma, age related macular degeneration, diabetes) then the eye struggles to produce a sufficiently clear image at any focal distance. Therefore these lenses are only suitable for eyes with no other problems. It is also crucial that the lens power is measured as accurately as possible prior to surgery which may require several visits. Even with the latest measuring techniques there remains around 5-10% patients who will be unhappy with the residual amount of spectacle prescription required and who may request additional laser refractive surgery.
Comfort multifocal intracocular lens with inferior high power reading segment
Comfort multifocal intraocular lens in position behind iris following cataract removal
I have found that the best quality of image, and happiest patients, are those that have a low power additional add for reading of 1.5 dioptres. This allows 90% of activities to be carried out without spectacles including computer work and most text. Avoidance of higher magnification for very small print provides a better quality of image for both near and distance. In the vast majority of my patients I therefore now implant the “Comfort” multifocal lens as pictured below. The design of this lens has a higher power segment at the bottom of the lens and results in minimal side effects more commonly seen with other lens designs such as glare and halo from bright lights often noticed with car headlights at night.
The comfort lens is also available with a toric component to allow for correction of astigmatism and further decrease the requirement for spectacles post operatively.
Disclaimer : The information provided in this website is intended as a useful aid to general practitioners, optometrists and patients. It is impossible to diagnose and treat patients adequately without a thorough eye examination by a qualified ophthalmologist, optometrist or your general practitioner. Hopefully the information will be of use prior to and following a consultation which it supplements and does not replace.
