At the recent inaugural MillennialEYE Live meeting in Austin, several leaders in the field debated the current strategies for managing presbyopia and the hope for future therapies to come. The debate is real, as our current strategies do little to “treat” presbyopia, but rather offer patients a means of coping with the disease. A review of corneal and lenticular approaches for dealing with presbyopia was provided, but the discussion also touched on the promise of pharmacologic or scleral manipulation as a means of treating presbyopia.
CORNEAL APPROACHES
At the simplest level, corneal treatment of presbyopia involves the use of laser vision correction to provide patients with monovision. This is certainly a reasonable approach, and, in fact, several studies have shown results to be fairly comparable to the use of multifocal IOLs. Laser correction is extremely precise, predictable, and safe. It also allows for the treatment of concurrent ammetropia and can be trialed by patients to determine their tolerance prior to surgery. However, monovision is not perfect. Dysphotopsias can be present, and there is a balance that needs to be maintained between the reading focal point and the loss of depth perception due to anisometropia.
More complex treatments incorporating laser technologies in the cornea involve the use of Intracor as well as PresbyLASIK and Supracor to create a what is, in essence, a multifocal cornea using a femtosecond laser or excimer laser, respectively. Although these treatment strategies are not currently approved by the FDA, the future of corneal treatments looks promising with the use of inlays on the cusp of FDA approval. Early data show inlays to be well tolerated, with a 6-line increase in near visual acuity. The additional advantage involves the lack of a fixed focus, so reading acuity is maintained without the loss of functionality as patients age.
LENTICULAR APPROACHES
Currently, lenticular treatments seem to be the most commonly employed strategy by those at ME Live. Most would agree that presbyopia is not a corneal disease, but rather a lenticular disease, and thus we should be addressing the problem directly. Lenticular treatment offers the ability to customize options to a patient’s needs with the use of monovision, accommodating IOLs, or mutifocal IOLs. However, the same limitations that were discussed with monovision in keratorefractive procedures are present with lenticular treatment. Accommodative technology isn’t as successful for presbyopia correction as most would have hoped, and multifocal IOLs have the disadvantage of dysphotopsia as well as a fixed focal point. While lenticular strategies have several limitations, they also seemed to hold the most promise for the future.
PHARMACOLOGIC THERAPIES
An exciting new development is the use of pharmacologic therapies for presbyopia correction. Currently under investigation, the use of pharmacologics is based on the concept of creating a small-aperature optical system, which we know works for presbyopia by expanding depth of focus. Early pilot studies show a significant percentage of patients who tested 20/30 or better at near. In addition, no myopic shifts were seen, preserving distance vision. Although pharmacokinetics would be a limiting factor, the duration of effect lasted between 8 to 16 hours for patients. This is an exciting development that seems to offer a benefit for a select subgroup of patients, specifically emmetropes and mild myopes.
Finally, the use of scleral expansion devices was discussed at ME Live, with data showing excellent results. Based on Schachar’s theory regarding the loss of accommodation, scleral expansion works to increase the distance between the sclera and equatorial lens, allowing for better zonular contraction. Four scleral pockets are created to allow for PMMA implants in the oblique quadrants. Although the results are not instantaneous, advances in the technology have allowed for faster results that seem to improve over time. This binocular treatment induces no dysphotopsias or loss of contrast sensitivity and maintains distance acuity while providing more than 90% of patients with J3 or better near vision.
CONCLUSION
The treatment of presbyopia is difficult and varied, to say the least. Each approach has advantages and disadvantages that make outcomes far from perfect. It may be that there never will be a one-size-fits-all approach and that several modalities will need to be offered in order to manage individual patients and their individual demands for near visual acuity. At the end of the debate, it was unanimously agreed that while our current technologies offer some help in managing presbyopia, the true treatment of this disease is still out on the horizon.
