Once a certain age is reached, presbyopia is almost unavoidable. Indeed, the deterioration of near vision is one of the most common optical ailments affecting the over 40 population. There are a number of treatments available for this condition, including reading glasses, contacts and corrective surgeries. However, for a large part of the past decade, there have been efforts to develop a topical treatment for presbyopia to help limit the need for corrective lenses and surgical procedures.
There are a few theories as to why presbyopia develops. Over time there is a change in the power of the optical lens. One theory suggests that the shape of the lens — changes in diameter and curvature — results in the increase in power of the lens. Another theory suggests that changes to the pliability of the lens cause this power increase. Spectacle, contact lens and surgical treatments for presbyopia have significant drawbacks, but the development of eye drops could make treating this common condition more convenient and less invasive.¹
Data Shows Drops Work
A recently published eight-year, retrospective study² from Benozzi et al., concluded that “presbyopia drops [one bottle of pilocarpine and diclofenac preservative-free eye drops], self-administered twice a day, seems to be sufficient to give spectacle independence for near visual tasks, in people with emmetropia with presbyopia.” The authors added that this is an efficient treatment for patients in their 40s until their 60s; it was deemed viable as an alternative to lenses and surgery.
Further, the authors continued that topical treatment can be viable in treating presbyopia. In their study, patients administered drops twice a day. After eight years of follow-up, the large majority of patients showed little to no adverse effects. They stated, “all of the patients achieved remarkable improvements of UNVA (uncorrected near visual acuity), and UDVA (uncorrected distance visual acuity) was not clinically affected.” Thus, patients experienced relief from an inability to focus on near objects, while distance vision was unaffected.
Another study³ showed “a progressive improvement in near vision with topical lipoic acid choline ester (UNR844) treatment during the 91 days of dosing.” This study showed that this treatment improved the sight of the trial subjects with minimal adverse effects. These trials are exciting indications of the future viability of topical presbyopia treatment.
On adverse events
Of course, there are some adverse effects to taking the drops. A number of patients in some clinical trials experienced burning once the drops were administered; however, most did not end the trial because of this.² With any topical treatment there is the risk of discomfort, but the good news is that the drops studied in clinical trials to treat presbyopia seem to only have caused minor discomfort. There is also concern regarding the effect these drops might have on distance vision.
Unfortunately, since topical treatment of presbyopia is still in its clinical trial phase, there will need to be a lot more research done before there is a clear idea of what the long-term effects will be.
The Future is Coming into Focus
This treatment has the potential to change the world of optometry. Most clinical trials of presbyopia topical treatments have shown successful improvement of near vision with only short term and limited negative effects. If these drops continue to show consistent benefits then the option to treat presbyopia without lenses or surgery would be a massive achievement. Several companies have taken up this challenge and many new treatments may be available by the beginning of next year.
The front runner is Allergan, an AbbVie company (Zurich, Switzerland), which has just submitted their topical presbyopia treatment for FDA approval. The treatment, AGN-190584, works by constricting the pupil (or miosis), and enhancing depth of focus on near objects. Clinical trials have shown success with limited adverse effects and there is significant hope regarding endorsement.
Another drop that has been developed is PRX-100. This treatment was developed by Presbyopia Therapies in San Diego, California. The company uses a miotic agent which constricts the pupil. This may prevent any harm to the patient’s distance vision because there is no accommodation.4 The company reported Phase 3 FDA clinical trials began in 2020.
Eye Focus (OSRX Pharmaceuticals, Montana, USA) also utilizes the process of miosis. However, this product uses a combination of medications in order to produce the desired effect, restricting pupil movement. The combination, including pilocarpine, phenylephrine, pheniramine and ketorolac, function together to preserve distance vision while improving near vision. Because this treatment uses a combination of medication, it is not subject to the same FDA scrutiny. This means that Eye Focus may become available without having to wait for the approval of the FDA.4
While many companies are focused on miosis, Novartis (Basel, Switzerland) has taken the lens restoration approach to presbyopia treatment. Novartis partially funded a recent study on topical lipoic acid choline ester eye drops.³ These drops work by softening the lens so that the effects of presbyopia are minimized. Though results of long-term use are still unknown, there is potential that this treatment might reverse age-related lens hardening.
There are many companies now actively researching presbyopia eye drops. It is likely that they will become a viable optometric option in the near future. Not only are there topical treatments that correct pupil function, there are also treatments that soften the lens and thus combating the processes of eye aging. This healthy competition ensures that the products that are approved and accepted by eye care specialists will offer the greatest benefit to the patients. This will also give optometrists another avenue in which to connect with their patients and provide continued care.
Looking toward the future, topical presbyopia treatments will likely become a safe alternative to surgery and lenses. They will also decrease the stigma around a presbyopia diagnosis. In the near future, their patients will no longer be limited to invasive surgery or cumbersome lenses, they will be able to live more comfortably based on the ingenuity of pharmaceutical companies and of their optometrists.
References
- Grzybowski A, Markeviciute A, Zemaitiene R. A Review of Pharmacological Presbyopia Treatment. Asia Pac J Ophthalmol (Phila). 2020; 9(3): 226–233.
- Benozzi G, Perez C, Leiro J, et al. Presbyopia Treatment With Eye Drops: An Eight Year Retrospective Study. Transl Vis Sci Technol. 2020;9(7):25.
- Korenfeld MS, Robertson SM, Stein JM, et al. Topical lipoic acid choline ester eye drop for improvement of near visual acuity in subjects with presbyopia: a safety and preliminary efficacy trial. Eye (Lond). 2021;35(12):3292-3301.
- Davidson J, Kimbro P. Coming soon: Presbyopia-correcting eye drops. Modern Optometry. 2020 Sept. Available at www.modernod.com/articles/2020-sept/coming-soon-presbyopia-correcting-eye-drops. Accessed on April 24, 2021.