Managing presbyopia in cataract patients

The elimination of the most common refractive complaint, presbyopia, and the restoration of normal vision by simulating accommodation, greatly enhances the quality of life of many patients. Consequently, it is becoming more and more common for presbyopic patients with cataracts to request spectacle independence, particularly because the advent of LASIK has increased patient expectations and because the demands of everyday life may make glasses inconvenient and aesthetically unpleasing.

Thankfully, we do have several treatment options currently available to us for those cataract patients seeking to alleviate the symptoms of presbyopia, some of which I will now discuss.

Monovision

Accommodative IOLs

In my opinion, those patients who do not desire monovision are suited to accommodative intraocular lenses (IOLs). Equally suitable are hyperopic presbyopic patients where the glare and halo effects of multifocal lenses may be undesirable. Post H-LASIK patients and post presbyLASIK patients are also good candidates for accommodative IOL implantation, however, accurate lens power determination can be challenging in these cases, hence caution is urged.

I find that the optimum visual result can be obtained with these IOLs if one eye is slightly under-corrected by -0.5 D to
-0.1 D. In the dominant eye one should aim for +0.5 D to
-0.5 D and, in the non-dominant eye, I tend to aim for
-0.5 D to 1 D, thus "a mild monovision".

Multifocal IOLs

Currently, multifocal IOLs might offer substantial benefits to patients who seek improved visual acuity following cataract surgery.

The first multifocal lenses were implanted in the late eighties and early nineties with variable success, however, improvements in surgical techniques, lenses and instrumentation over the last decade have seen success rates rise dramatically. Consequently, multifocal IOLs have increased in popularity certainly in the past year and particularly in those patients who do not like or are not accustomed to monovision.

Some surgeons, however, remain unconvinced because of concerns pertaining to loss of best corrected visual acuity, increased chair time, unwanted visual images and high patient expectations.

It is absolutely imperative that the correct procedure, IOL type and power are chosen for each patient to increase the chance of success. Typically, I perform a full ophthalmic examination and include assessment with the IOL Master (Carl Zeiss Meditec) and Orbscan (Orbtek) topography. I then plan my surgery and select the correct lens for the patient, and I follow this with counselling and informed consent.

Hyperopic presbyopic patients, high hyperopes, emmetropic cataract patients who want spectacle independence, post LASIK patients, high myopes and patients where an accommodative IOL cannot be used, are suitable for multifocal implantation. In general, hyperopes and moderate to high myopes benefit most from these lenses, although there have been instances when patients that fall into this category still do not adapt well to these IOLs. It is essential therefore that those patients with unrealistic expectations are avoided.

Selecting the right patient

Relative contraindications are patients with small and/or irregular pupils, age-related macular degeneration, uncontrolled diabetes or diabetic retinopathy, uncontrolled glaucoma, macular disease, recurrent inflammatory eye disease, keratoconus, irregular corneas and previous radial keratotomy.