Monovision Cataract Surgery
April 16, 2010DrHovanesian 2 Comments »Going Back to Monovision Cataract Surgery
Surgeons are Going Back to Monovision Cataract Surgery, and It’s Working
Several colleagues of mine have recently informed me how happy they and their cataract patients have been with monovision. I credit Jay McDonald of Fayateville, Arkansas for reintroducing me to this approach. Look for an upcoming article in The Premier Surgeon where I interview Jay for his take on this topic.
In a time when we have an expanding line of presbyopia-correcting implants to offer, why would they consider such an old-fashioned approach? Because it’s simple and it works. Despite perceptions about this age-old approach, monovision with an IOL:
- does not require a contact lens trial. In fact, a trial should probably be avoided. Cataract patients who have never before worn contacts tend to become more bothered by the experience of wearing CTLs than the monovision itself. They are more likely to reject the concept on the basis of the CTL’s unfamiliarity rather than the anisometropia.
- does not require significant anisometropia. Targeting plano in the dominant and -1.25 to -1.5 diopters in the non-dominant will yield high-grade intermediate and near vision. Some patients may need to increase their working distance for some tasks like needlepoint. Naturally, they can also resort to readers that balance both eyes for very near.
- does not reduce stereopsis significantly. Patients who enjoy playing tennis, for example, do not complain of inability to function on the court. Postop patients typically can be measured to have high-grade stereo acuity.
- does not reduce contrast sensitivity significantly. While some reduction in high spatial frequency contrast sensitivity occurs during distant tasks in the non-dominant eye, the patient can compensate. The brain “shifts” its attention during these tasks to the dominant eye, which has perfect contrast sensitivity. You won’t find “perfect” contrast sensitivity in an eye with a multifocal.
Additional advantages of monovision cataract surgery:
- Unlike multifocal implants, the very mild loss of contrast sensitivity at distance is completely reversible. Many of my patients would much rather spend their day without glasses, even if they have to put on a pair of specs to drive at night.
- Monovision can be offered with a variety of implants. My personal preference is to use a monofocal implant with either negative asphericity like Tecnis (AMO, Santa Ana, CA) or the AcrySof IQ (Alcon, Ft. Worth, TX), or a neutrally aspheric lens like the Softport AO (Bausch & Lomb, Aliso Viejo, CA).
- Monovision allows the surgeon to offer a refractive procedure without the added cost of a multifocal or accommodating implant. This saves the patient thousands of dollars. Note it is appropriate to bill for refractive services incident to this procedure, including all non-covered services, such as refractive evaluation, topography, pachymetry, limbal relaxing incision, and refractive enhancements. The Corcoran Consulting Group (www.corcoranccg.com) has developed audit-proof guidelines for the financial aspects of this procedure, which are beyond the scope of this blog.
To be sure, there is a fair bit of work involved for the surgeon, just as with a high-tech IOL. Getting the postop refraction to be perfectly spherical and nailing emmetropi in the dominant eye are essential elements of success; enhancements are occasionally necessary, and patients do have the same demands as the higher-paying customers who have PC-IOLs. But there’s something elegant about using nature’s gift (the brain’s plasticity) to give patients spectacle freedom, and in the future I’m going to be doing more monovision.
November 28th, 2011 at 9:00 am
Regarding the monovison technique, it sounds ideal for most folks wanting the sharpest distance, however there may a lot of people who may prefer a little different approach – i.e., skewing the visual profile a little more for near-intermediate vision.
This approach might allow an individual to be glasses-free more of the time. — e.g., only needing to use readers for very small print, or needing glasses when the sharpest distance vision is required (e.g. driving ).
For example, this approach should allow folks to walk down the aisle of a supermarket, pick up a can, and be able to read the label without glasses, or use their cellphone without having to put a pair of glasses on.
In other words, it might be desireable to compromise a bit on the distance correction (e.g., correction to 20/40), in order to have very good near and intermediate vision.
November 28th, 2011 at 10:03 am
Phil, I agree with your thoughts very much. In fact, in the “near” eye, I typically aim for a refraction of -1.25 to -1.5. This yields distance vision at 20/40-20/60 (as you suggest) while maximizing intermediate and allowing adequate near for most tasks. Everyone adapts well to this very mild anisometropia, and patients generally love it! Thanks for your comment.