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Expect increased investment, innovations in the field of presbyopia treatment
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According to the 2012 U.S. Census Bureau Statistical Abstract, there are 140 million people in the U.S. who are in the presbyopic age group of 40 years and older. Compared with the approximately 80 million myopes, 90 million hyperopes and 90 million individuals with 1 D or more of astigmatism, presbyopia is arguably the most common refractive error in America.
In some Asian countries, where there is a smaller senior population and the myopia prevalence is nearly double the 25% prevalence found in the United States, Europe and Latin America, myopia dominates, but it is estimated by Market Scope that there will be more than 2.1 billion presbyopes in the world by the year 2020.
As an emmetropic — now slightly hyperopic — presbyope, I can personally affirm that presbyopia represents a significant visual handicap in daily living and negatively impacts quality of life. If there were currently a treatment for the prepresbyopic myope with an identical set of outcomes and risks as those present in LASIK or PRK, I would have surgery in a heartbeat, as would hundreds of thousands of other unhappy presbyopes around the globe.
Unfortunately, today we do not have a procedure for the emmetropic or ametropic presbyope that can consistently deliver 20/20 distance, intermediate and near vision in both eyes; binocular summation at all distances; a full visual field and high-quality photopic, mesopic and scotopic vision with minimal side effects and surgical complications. We do, however, have several procedures that generate outcomes good enough to satisfy select patients.
Whether using corneal- or lens-based refractive surgery, or a contact lens fitting for that matter, the optical principles we can employ are generally the same. We can do monovision. We can use multifocal optics. We can do modified monovision with a monofocal optical system in one eye and a multifocal or enhanced depth of focus optic in the second eye. We can increase depth of focus with mild astigmatism, spherical aberration or small-diameter aperture optics, or we can engage electronically activated devices that change power or reduce aperture size in response to an electrical stimulus.
Driven by the significant size of the opportunity and the relative affluence of the older presbyopic-aged patient, enormous investment of financial and human capital is occurring into surgical procedures to treat presbyopia. Since these are well-discussed in the accompanying article, I will simply add a few personal observations.
Monovision remains the most popular option whether the optical system is a contact lens, a corneal-reshaping procedure or an IOL. Modified monovision, where a monofocal optical system is retained for the distance eye and a multifocal or increased depth-of-focus optical system for the near eye, is also popular. Multifocal optical systems continue to improve, but patients value high-quality vision, and night vision symptoms and the loss of contrast sensitivity continue to present a significant barrier to adoption of multifocal optical correction.
In addition, we have found that with monovision, modified monovision and multifocal vision, the refractive target must be hit with excellent accuracy to generate high patient satisfaction. While it was initially hoped that being within 1 D of the refractive target and generating less than 1 D of astigmatism would be good enough to achieve high patient satisfaction, we now know that even as little as 0.5 D of residual astigmatism can degrade the optics of a multifocal IOL enough to generate a dissatisfied patient.
Unhappy patients, even in small numbers, are a significant barrier to new technology adoption. On the other hand, happy patients and happy doctors go hand in hand. Targets are more easily hit with contact lenses and corneal refractive surgery, but on-target outcomes in refractive cataract surgery remain elusive. Advancing technology as exemplified by intraoperative keratoscopy; toric, monofocal and multifocal IOLs; intraoperative alignment systems like the Alcon GPS Verion System and the WaveTec and Clarity intraoperative aberrometry devices, and perhaps the application of femtosecond lasers to generate more reproducible capsulotomies and incisions, are moving lens-based surgeons’ refractive outcomes closer to those generated by contact lenses and corneal refractive surgeons. However, there is still much room for improvement in the typical surgeon’s ability to hit his or her patients’ desired refractive targets.
Another elusive goal is an accommodating IOL that consistently delivers accommodative amplitude of 3 D or more. A decade ago, I thought we would have one today. Biology in the form of capsular contraction and inconsistent retention of capsular elasticity may represent an insurmountable barrier unless overcome by a not-yet-discovered treatment to the capsule itself. Retention of a clear elastic posterior capsule after cataract surgery is a major unmet need in ophthalmology. Investment is beginning to attack this nemesis of a successful in-the-bag accommodating IOL, but a solution seems years away. This is driving research into ciliary body-driven accommodating IOLs, electroactive lens implants and methods to increase depth of focus, including small- diameter apertures and hyperapsheric optics. Each of these shows promise but remain years away from commercial launch in the U.S.
One threat to continuing innovation remains the extraordinarily time-consuming and expensive pathway to regulatory approval in important countries including the U.S., Japan and now even China. The expanding timelines and expense to bring a product to market is discouraging investment in the biomedical field, as evidenced by the significant decline in venture capital company money available to invest in new innovation and a reluctance of many major strategists to invest in truly disruptive technologies, favoring lower-risk incremental improvements in current products.
A recent Harvard Business School study confirmed that the companies with the highest long-term success remain those that invest significantly in research and development, and that the greatest returns on investment continue to accrue to those companies that develop truly disruptive technology with first-mover status in the marketplace.
It is clear to me that there is great opportunity waiting to be harvested in the surgical correction of presbyopia field, both for the ophthalmic industry as well as the ophthalmic surgeon. In spite of the always-present risks and threats, the opportunity remains high for investment in presbyopia treatments, and innovative ophthalmologists working together with innovative scientists, entrepreneurs and investors can be expected to deliver much progress in this area in the next decade.