In surgery it is hard to try before you buy. It is therefore important to assess the patient’s true visual needs prior to embarking on cataract surgery or lens exchange, for an incorrect decision can be difficult to rectify. Not all patients seek emmetropia and many are happy with spectacle correction for reading following cataract surgery or even being left myopic. It is after all what most in that age group have been used to. Monovision in the non-dominant eye, particularly a low minus of 1D or less, has a pseudo-accommodative effect giving more bang than expected for the buck. Many patients then find they need readers only for fine print, much to our surprise.
Having been an early adopter of both the multifocal lens technology and the accommodative lens where do I feel we are at present? My initial experience with the Restor Multifocal was a series of highs and lows. Some wonderful results, grateful patients then a few grumblers, including some in whom lens removal and exchange was required and many more requiring refractive laser correction than I would have suspected. That was back some 7 years ago and after a first 100 back then I implanted very few Restor lenses until the last year.
What has changed? The new Restor is aspheric, has a decreased reading add giving a more comfortable reading distance and most importantly has incorporated a toric correction allowing for astigmatism correction down to 0.6D. The result has been significantly fewer comments from patients about haloes at night and I have had no issues with those who drive at night. The improved lens formulae and the toric lenses have meant 40% of my patients have a toric lens implant. No lenses have been explanted so far.
There are other manufacturers of lens implants that also offer multifocality but not all have a toric option. The particular acrylic material and lens design makes the Restor toric very stable from the moment of implantation with little likelihood of lens rotation off axis, a key to a predictable outcome.
Whom do I exclude from consideration of a multifocal lens today? The myope whose expectations re near vision are so much greater, any difficulty in lens power estimation (Keratoconus, high astigmatism, previous refractive surgery) and any suggestion of macula disease, including any diabetic retinopathy and amblyopia. Care must be taken to reduce the likelihood of CMO post operatively and for these patients especially there is a role for the NSAID drugs (Voltaren or Acular) postoperatively.
Personally, I will not use a multifocal on an emmetrope looking for presbyopic correction. I don’t believe the risk justifies the end result and would still prefer a monovision refractive laser in this situation.
Who does best? The initial hypermetropes appear to enjoy the benefits, especially those greater than +2D. So far I have not required a refractive laser top up in these more recently implanted eyes but expect with the refractive surprises that occur from lens positioning that they will be needed for some. I also feel patients do best with bilateral implantation and plan for this a week apart or as soon as the patient can schedule the second surgery.
My current practice involves less than 20% Restor multifocal lens implantation in my cataract patients and over 80% (in the refractive lens exchange grou)p are Acrysof Spherical or toric with a few Raynor Toric for very high astigmatism.