Presbyopia-correcting drops may benefit some pseudophakic patients
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As presbyopia-correcting drops from different companies go through clinical trials and receive U.S. marketing approval, there is excitement about what these drops could mean for middle-aged presbyopes who dislike reading glasses.
But there are at least three key subsets of the pseudophakic patient population that could also benefit from pupil-modulating drops.
1. Patients with complex corneas
Post-corneal refractive surgery patients already know the value of spectacle independence, but many of them are not good candidates for premium lenses. Biometry in post-RK eyes, for example, can change from day to day and vision can fluctuate throughout the day, making it difficult to accurately target refractions. A small aperture, either implanted at the time of surgery or pharmacologically induced with presbyopia-correcting drops after surgery, has the potential both to reduce spectacle dependence and to improve distance image quality by reducing aberrations. Similarly, those with ectasia, keratoconus, irregularities due to corneal dystrophies (eg, Fuchs’ corneal dystrophy, epithelial basement membrane dystrophy) and corneal scars may also do better with a smaller pupil after cataract surgery.
2. Those whose spectacle independence goals were not met
We have all seen presbyopia-correcting IOL patients who did not get the full range of uncorrected vision they hoped to have. Perhaps they had a low-add multifocal or an extended depth of focus (EDOF) IOL that was not designed to provide near vision. We can now offer these patients a noninvasive way to enhance their near vision after a disappointing surgical result. I am not concerned that a topical drop could cannibalize our premium IOL business. Most patients who know they want spectacle independence will prefer a presbyopia-correcting IOL over daily drops. But for patients who are not good candidates or who do not achieve the desired result, drops will allow us to fine-tune the outcome.
Source: Cathleen M. McCabe, MD
3. Bifocal wearers
Patients who had standard monofocal IOLs and are now wearing bifocals could benefit from presbyopia-correcting drops. While they may still need spectacles for distance, we can increase safety and improve depth of field by getting rid of the bifocal. Our older pseudophakes are already at risk for falls, and that risk is increased when looking down through the near add portion of bifocal lenses, particularly when going up or down stairs. Fall risk is not inconsequential; fall-related injuries can launch a downward spiral of hospitalization and lost independence that is best avoided.
Implementation in ophthalmic practices
The majority of candidates for presbyopia-correcting drops will likely present to primary eye care practices. However, I believe that surgical ophthalmologists will also find ample opportunity to prescribe these drops.
Preoperatively, we can offer drops as an interim solution to patients in their 50s or 60s who are seeking LASIK but would be better served to wait for lens surgery. I also think presbyopia-correcting drops will be a great tool to offer proactively to patients in whom I plan to implant an EDOF lens because they are not good trifocal candidates. My guidance to these patients, who I know hope to be out of glasses altogether, is that they might need a pair of low-add readers after surgery. In the near future, I will be able to say, “We have other tools we can use after surgery, including eye drops that may enhance the effect. Let’s see how you heal first.” The ability to modulate the pupil with a safe and well-tolerated topical drop may also increase surgeons’ comfort level with presbyopia-correcting IOLs. I expect that a smaller pupil will help us manage low levels of residual astigmatism, improving both distance and near vision.
Postoperatively, when pseudophakes complain about their results and seek an enhancement or an IOL exchange, we will have the opportunity to educate them about drops. Previously, we have had little to offer these dissatisfied pseudophakes.
I would encourage surgeons to look closely at these new drops as they enter the market. Although the active ingredients (eg, pilocarpine, carbachol, brimonidine) might be familiar, forthcoming presbyopia-correcting drops will use lower concentrations of these agents and much more advanced formulations that are likely to mitigate the side effects we typically associate with miotics. It will be important to review study data demonstrating that drops are well tolerated and do not degrade distance vision. I am personally not too worried about light restriction from pupil modulation in pseudophakic patients. However, if there are any problems, the patient can simply discontinue the drops.
Finally, we must also give careful consideration to the ocular surface impact. Pseudophakes are in an age group that is prone to ocular surface disease. It will be important to learn more about the surface toxicity associated with the preservatives or the active ingredients in these drops. A longer duration presbyopia drop would not only protect the ocular surface better by reducing the number of instillations per day, but also help patients avoid frustration with the drop wearing off.
Ultimately, I view presbyopia drops as an important adjunct for the lens surgery practice of the future.
- For more information:
- Cathleen M. McCabe, MD, can be reached at The Eye Associates, 6002 Pointe West Blvd, Bradenton, FL 34209; email: cmccabe13@hotmail.com.
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