The Implantable contact lens is an option for those who are not suitable for LASIK or PRK and who have been told that they are not able to be helped with vision correction
The Alcon Cachet lens was briefly removed from use after a number of recipients were found to have unaccetable endothelial cell loss. Most of these patients either had shallow anterior chambers or were of asian origin. These patients either had their lens explanted or were closely observed. The majority of patients had no problems and did well. Now the lens has been cleared and is again available for use. In an earlier post of mine I mentioned that its withdrawal left a hiatus for certain patients. I also mentioned that the ICL (Implantable Contact lens), in my opinion was not a viable substitute due to problems with cataract formation. After much research I have changed my mind about this and will shortly post an article about this. So what is the Cachet lens exactly and why is its return good news? Well firstly its important to understand that there are limits to what can be done with vision correction. The currently available options include, LASIK, PRK, refractive lens exchange, the ICL, the Artisan lens and the Cachet lens. In addition there are a couple of other approaches (such as monovision, multifocal IOL and Kamra inlays) to deal with the problem of presbyopia. This is another topic however. These approaches have limits to who can have it, and how much of a problem they solve. In the case of LASIK or PRK, the limitation is simple math. How big the refractive error is and how much cornea there is to work with. So a high script and a thin cornea just doesn’t work. Further, refractive lens exchange is limited to presbyopic patients due to the loss of accommodation that comes with lens exchange. This means the over 50’s crowd. One may argue that a +12 hyperope who is 30 years old may not consider that loss of accommodation is a big deal compared to being free of glasses most of the time however. It is the pre-presbyopic crowd with big number glasses that stand to benefit from the Cachet lens. An Alcon Cachet lens. This lens is implanted in the anterior chamber and sits in front of the iris. It therefore leaves the natural lens untouched. It is a so called angle supported lens. The procedure for implantation is very straight forward. It is implanted through a small 2.7mm wound under viscoelastic. The pupil is firstly constricted to prevent touching the natural lens. The viscoelastic is then removed and the procedure is over. The ideal candidates are myopes between 6 diopters to 16 diopters. LASIK is simply not an option for more than 10 diopters or in some cases even less if the cornea is thin. In order to avoid problems with endothelial cell loss, the anterior chamber has to be at least 3mm deep. Prior to the procedure, an endothelial cell count is performed and yearly thereafter. The beauty of this lens is that it can be removed at any time, restoring the eye back to normal. So what are the drawbacks? Well as mentioned, the potential for accelerated endothelial cell loss. This can be minimised by ensuring that the anterior chamber is adequately deep and by follow up annually. Further, it is not suitable for hyperopes and it is not able to correct any astigmatism which either needs to be dealt with a limbal relaxing incision or an ICL instead.