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Larger optic diameters and extended depth of focus
Over 600,000 ICLs (intraocular collamer lenses) have been implanted since 1992. The highly hydrated cross-linked collagen hydrogel material they are made from has an impeccable biocompatibility record, and the surgery is technically easy to perform. Although similar posterior chamber phakic IOL designs are starting to emerge, the Visian ICL remains dominant in the worldwide market and has stood the test of time.
Based on good results in FDA trials, I started ICL implantation at Moorfields in 2003, and went on to perform quality of life studies demonstrating clear benefits for ICL implantation over contact lens and spectacle wear for patients with refractive errors outside the standard laser vision correction range. For many young patients, the surgery is transformative.
So what’s not to like? Concerns over cataract development have largely evaporated since the V4c (centreflow) technology was introduced; but sizing remains problematic. Whatever pre-operative measurement method is used, about 1 in 40 ICLs need to be exchanged because of a high or low vault. Again, this is technically easy, but I would recommend flagging sizing issues up with patients during consent so that they are not surprised or unduly worried if an exchange is indicated. Patients also need to be aware of arcs and halos in the adaptation phase. Overall visual quality is very good though, refractive retreatments are seldom required, and I have never yet had to remove an ICL because of unhappiness with quality of vision.
ICLs are not currently available for NHS patients. This is frustrating because they work particularly well in patients with high refractive errors after corneal transplantation. We recently also had a very nice result using an ICL as a temporary platform allowing us to perform DMEK successfully in a young, aphakic, vitrectomised patient at high risk of transplant rejection. My hope is that an NHS funding solutions for these niche therapeutic indications can be found soon.
Pre-loaded lenses are not yet available, and one of the barriers to getting started with ICL implantation is learning to load the lenses into the injector. A short video with some tips on loading up is embedded below. Over the past year, we have been using the newer EVO+ larger optic ICL with good results, and I am looking forward to working with extended depth of focus ICLs currently in the pipeline.
Increasing use of ICLs in post-presbyopic patients is an important emerging trend. ICL implantation is lower risk than refractive lens exchange, and recent French population data shows clearly that the risk of retinal detachment after cataract surgery in myopia drops with age. So, even if ICL implantation is just a stepping-stone to lens exchange in later life, it may still be a safer option than lens exchange ab initio for patients in the 45+ age group who are out of range for laser vision correction.