In this article, Dr Vryghem weighs up the pros and cons of visual revalidation techniques and compares the currently available techniques in a clinical setting.
As a result these patients show a strong interest in surgical visual revalidation techniques. This is especially true of patients who are intolerant to contact lenses. My strategy in managing such patients is to target emmetropia, and I use a variety of approaches to achieve this goal depending on each patient's unique situation.
Weighing the pros and cons of visual revalidation techniques
For instance, although TG-PRK has the advantage that it recentres the conus making the cornea more regular, it is limited by the requirement that it must be performed either after or simultaneously with CXL and that it is non-reversible. Furthermore, general guidelines recommend that surface ablation must not be performed deeper than 50 μm, which limits the extent of ametropia that can be corrected.
With phakic IOLs, high myopia and astigmatism can be corrected and the procedure is theoretically reversible, however, it is an invasive intraocular technique in which the cornea remains unchanged. Furthermore, preoperative CXL is required in young patients and those with progressive keratoconus.
ICRS are a less invasive treatment option that are also easily reversible. They can be used to treat high levels of myopia and astigmatism and also recentre the conus and make the cornea regular. Some surgeons suggest that ICRS can be implanted without prior CXL, even in young or progressive keratoconus patients; however, I prefer to use CXL to stabilize the keratoconus before implanting the ICRS. A seeming disadvantage of ICRS is that they often cause visual symptoms such as halos, although most of my patients claim to not be too disturbed by them.