Almost everyone will need to undergo cataract surgery in their lifetime. Cataract is a part of ageing process causing clouding of our natural lens. When our natural lens becomes cloudy, we will slowly lose our vision. Fortunately, this cloudy lens or cataract can be easily removed. During cataract surgery, eye surgeon will remove the cataractous lens through a very small incision using a phacoemulsification technique. An artificial lens will be inserted as a replacement. After cataract surgery, patients will experience improvement in their vision that was previously impaired by the cataract. Most patients will be offered a standard monofocal intraocular lens replacement. Monocular lens has one point of focus. This means patients will have good vision for either distant or near. If the distant vision is clear, the patient will need to wear spectacles for reading and vice versa. To address this problem, new lenses have been developed that provide two or more points of focus. These are known as ‘multifocal’ lenses. These are designed to reduce the need for spectacles. While these lenses promise relative spectacle independence, a certain degree of visual compromise can still be anticipated. Patients with multifocal lenses may have some vision complains such as glare and seeing haloes. Most patients will be able to adapt or tolerate some minor glares or haloes while some patients may be severely impaired by the symptoms. Currently, in the market, there are different types of multifocal lens to cater for different patients. Patients who like to read may need multifocal lens with higher correction for reading. Patients that do a lot of computer work may prefer trifocal lens that also provides good intermediate vision. To address the complains of glares and haloes, a newer generation of EDOF (Enhanced Depth Of Focus) lenses claims to provide better balance of functionality while reducing unwanted glares and haloes, which may pose difficulty driving at night for some patients implanted with multifocal or trifocal lenses. With so many options of intraocular lenses available in the market currently, both patients and eye surgeons are in dilemma over which type to be implanted after cataract surgery. This is where good assessment and discussion with the patients prior to the surgery are needed. Different patients may tolerate glare and haloes differently. One patient may put lots of emphasis on reading small prints while another patient may need to do a lot of night driving. Another group of patients who do not mind wearing spectacles will be very happy with monofocal lens. As far as I am concerned, there is no single lens for that will suit all patients. With proper preoperative assessment and consultation, most patients will be delighted with the improvement in their vision after a successful cataract surgery.
by Dr. Thomas Law Ngo Hieng