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The rationale for pseudophakic monovision
The advantages of this presbyopia correction approach are now more difficult to ignore.
I have been emphasizing the unique benefits of pseudophakic monovision in this column for some time now. I have chosen to focus on this approach for two reasons.
 William F. Maloney |
First and foremost, you will not learn about it in our educational forums, where the agenda is typically dictated by industry’s marketing interests and presented at the podium almost exclusively by sponsored speakers. Obviously industry does not sponsor what is not in its own interest, and industry has no vested interest whatsoever in your learning about the advantages of pseudophakic monovision that utilizes a low-cost conventional IOL. Secondly, as the practical limitations of the alternatives become more clear, I am of the opinion that this approach is far and away the best method of pseudophakic presbyopia correction for the majority of candidates.
When writing these articles, I have often felt that I am whistling in the wind because, despite its benefits, pseudophakic monovision has remained the orphan of presbyopia correction. That is now changing as the advantages of this approach are steadily becoming more apparent to surgeons.
Unique advantages of pseudophakic monovision
Due to the additional preop tests involved, the noncovered surgeon fees are typically greater than with the alternatives. Further, the total cost to the patient is significantly less — usually around $1,000 per eye — with pseudophakic monovision because a conventional lens, not a premium-priced IOL, is used. This favorable financial equation translates into a much higher patient acceptance rate — roughly 65% in my cataract practice, compared to roughly 10% for the premium implants.
More importantly, the clinical result is typically better with authentic pseudophakic monovision where the outcome is not dependent upon a fixed reading range but rather is strategically selected according to each patient’s particular reading goals.
In addition, the period of time required for the result to feel completely natural is typically 1 or 2 days with pseudophakic monovision, not the 6 to 12 months of adaptation often seen with the multifocal or accommodating alternatives.
Why then has pseudophakic monovision only now begun to move front and center where it belongs in this presbyopia discussion? I began to learn the critical answers to this question at my initial course detailing this approach at last year’s American Society of Cataract and Refractive Surgery meeting.
Closing the perception gap
During the discussion period of that course, I saw how far removed my working knowledge of pseudophakic monovision — evolved from my experience with more than 2,000 cases of pseudophakic presbyopia correction since 1985 — was from that of most attendees. In my view, the conventional wisdom concerning the relative merits of this approach was clearly off the mark. The prevailing perception gap centered on three core misconceptions, which I have attempted to address in previous columns.
Misconception No. 1
Pseudophakic monovision has the same “iffy” acceptance rate as contact lens monovision.
Despite the emphasis on trial and error and the paucity of clinical assessments typically employed, contact lens monovision has an historical acceptance rate of about 65%.
Authentic pseudophakic monovision has an acceptance rate of 99%, in my experience. The difference is due mainly to the much larger anisometropic “sweet spot” from the pseudoaccommodation inherent in all conventional lens implants. Contact lens monovision is hardly an appropriate model for surgical monovision, yet it unfortunately remains just that in the minds of many surgeons.
From the column “Surgical monovision is not optometric monovision,” Sept. 1, 2006: “Pseudophakic monovision is much more than permanent contact lens monovision. Properly performed, the end result is highly predictable and provides a level of reading versatility not readily achieved with the current alternatives. … The common use of a contact lens trial to help predict surgical monovision success is emblematic of this holdover of the optometric model.”
Misconception No. 2
Pseudophakic monovision carries significant visual compromise.
There is only one compromise that typically accompanies authentic pseudophakic monovision: night driving dysphotopsia. However, because most cataract patients drive little, if at all, at night this is mostly moot and compares favorably to the full-time difficulties that can accompany each of the premium implants.
From the column “Monovision in name only,” Oct. 1, 2006: “Pseudophakic monovision is not monovision at all, but a specific class of binocular rivalry induced by an exact amount of anisometropia. Resolving just this sort of interocular image disparity is inherent in the neural circuitry of the visual cortex. That’s right; our brains are hard-wired for pseudophakic monovision. … Multifocality’s intraocular image competition has no physiologic precedent. Without a neural template to single out and convey the winning percept into awareness, a prolonged neuroadaptation period is needed. … As that work goes on, the haloed vision emblematic of truncated image distinction slowly moderates and often — but not always — gradually disappears.”
Misconception No. 3
Surgeons cannot charge the patient for the noncovered services performed with pseudophakic monovision because a premium IOL is not used.
The issue of noncovered surgeon charges has unfortunately been tangled with the May 2005 CMS ruling concerning the premium IOL device charge.
The additional facility charge for a premium IOL applies whenever such a premium IOL is utilized. This has been clear enough. Noncovered charges for the surgeon’s additional services are a different category, however.
The surgeon charges for refractive surgery such as presbyopia correction are independent of the device employed and are based solely upon the additional work principle.
From the column “Presbyopia correction: Handling the new patient charges,” July 15, 2006: “Noncovered charges for services provided by the surgeon … needs clarification. This is especially true for those cases in which the correction of presbyopia employs the pseudophakic monovision approach, which does not use one of the three designated premium presbyopia-correcting IOLs. … Noncovered services provided by the surgeon are limited to those specific tasks that constitute appropriate ‘additional work.’ … Changing from a conventional IOL to a premium … IOL without performing any additional tests or assessments … does not qualify as a noncovered service no matter how effectively this may happen to correct presbyopia in a given case.”
2007 pseudophakic monovision course
I will teach this course again at this year’s ASCRS meeting. Titled “Pseudophakic presbyopia correction: an objective assessment of current alternatives,” it is scheduled for Saturday, April 28, from 1 to 2:30 p.m.
With the perception gap hopefully closed, we can use this opportunity to focus solely on how to make this approach a thoroughly successful element of your presbyopia correction efforts.
In the April 1 issue
Finding each patient’s particular anisometropic sweet spot.
For more information:
- William F. Maloney, MD, is head of Maloney Eye Center of Vista, Calif., and a well-known teacher of cataract and lens-based refractive surgery techniques. He can be reached at 2023 West Vista Way, Suite A, Vista, CA 92083; e-mail: maloneyeye@yahoo.com. In the interest of objectivity, Dr. Maloney has no financial interest in any ophthalmic product and has no financial relationship with any ophthalmic company.
- Lens-based Refractive Surgery Column Mission Statement: To educate readers on all aspects of lens implant refractive surgery including presbyopia correction, refractive cataract surgery, refractive lens exchange and phakic IOLs.