By Daphne Chiew Le Min, School of Medicine, Imperial College London
Seeing as both myopia and cataract are increasingly common in our ageing Singaporean population, it is important to understand how either condition interacts with the other. Dr Joy Chan, Medical Director and Senior Consultant Ophthalmologist, International Eye Cataract Retina Centre, gave a lecture on the “Complications of Myopia: Cataract” at the Singapore Primary Eye Care Symposium (SPECS) 2019 held from 23-24 July 2019 at One Farrer Hotel.
Multiple studies have shown that cataracts do cause myopia, and this well-documented phenomenon – index myopia – occurs due to changes in the intrinsic lens proteins causing variation to the index of refraction of the crystalline lens. Myopia has also been linked most commonly to posterior subcapsular cataract, by multiple local and overseas studies. This association increases with high myopia, whilst conflicting evidence is present for other types of myopia and cataracts.
Dr Chan then spoke about the management of index myopia, emphasizing the importance of patient preference when weighing the various options. Talking through various treatment possibilities, she focused on cataract surgery in high myopes and mentioned the complications associated with such surgery in this sub-group of patients, such as the increased difficulty of surgery or more careful selection of intra-ocular lenses. Sudden decompression of the eye should also be avoided as it leads to increased traction and increased risk of retinal detachment post-surgery.
She also mentioned the importance of biometry, and that it would be more ideal to under- rather than over-correct for myopic patients should 6/6 vision not be achievable. It is also important to ensure patients with high myopia do not have other ocular pathologies present e.g., myopic foveoschisis and retinal detachment, as they are at higher risk. Finally, she concluded by summarizing the main things to keep in mind post-surgery, namely that refraction might take a short while to stabilize, and to watch out for refractory surprise.