By Daphne Chiew Le Min, School of Medicine, Imperial College London
There are many factors to consider when choosing an intraocular lens for cataract surgeryhttps://eyecataractretina.com/eye-conditions/instructions-for-cataract-surgery/. Dr Joy Chan, Medical Director and Senior Consultant Ophthalmologist at International Eye Cataract Retina Centre, gave a lecture on the “Choice of Intraocular Lenses for Cataract Surgery” at the Singapore Primary Eye Care Symposium (SPECS) 2019 held from 23-24 July 2019 at One Farrer Hotel.
Dr Chan began by skimming through a brief history of intraocular lens development and introducing the different types of lenses currently available in the market.
Starting with monofocal lenses, she described the differences between spherical and aspheric lenses, and summarised that although spherical lenses are cheaper, they can cause higher order aberrations which can affect the quality of vision in low light. She then spoke about multifocal and EDoF (Extended Depth of Focus) lenses which can allow a patient to be spectacle-free, but give poorer night vision as well as longer visual rehabilitation.
Moving on, she talked about toric lenses which have in-built astigmatism correction. She emphasized the importance of accurately measuring the amount of astigmatism present, as well as the importance of implanting the lens in the correct visual axis. She mentioned that every one degree off in implantation results in a 3% decrease in toric lens efficacy, which can affect the patient’s visual quality. Finally, she contrasted traditional and modern methods of visual axis marking, and praised the increased ease at which computer-guided visual axis marking allows for accurate lens implantation.
Lastly, she gave some tips regarding how intraocular lenses should be chosen. She cautioned against multifocal or EDoF lenses in patients with other pre-existing macular or retinal conditions as these patients may already have reduced contrast sensitivity. Consideration of patient factors such as age, current occupation and financial ability are also essential for ideal lens-patient matching. She also highlighted the importance of using the same type of intraocular lenses in both eyes. She concluded her talk by bringing up key traits that her patients should fulfil should they want multifocal lenses – i.e. they are very keen on spectacle-free close vision, are willing to accept compromises in visual acuity and are able to commit to operating on both eyes within a short period of time as the brain adapts more quickly if both eyes have same the multifocal lenses.