In view of current efforts to achieve pharmacological control of presbyopia, it is desirable to reach a compound or compound that improves reasonably well near vision without or with fewer possible collateral effects, such as pain and dim vision, and lasts a reasonable period of time. Our group developed a compound based on low-dose pilocarpine, brimonidine and oxymetazoline combined with sodium hyaluronate and bromofenac to achieve this goal. This compound performs better in improving NUCVA than pilocarpine or brimonidine alone, acting synergically, as we describe in ClinicalTrials.gov identifier NCT05006911. Benozzi reported a combination of pilocarpine (1-2%) and diclofenac to control presbyopia symptoms. Twenty percent reported eye burning and ocular discomfort after instillation. One percent discontinued the treatment, and 4% resumed using reading glasses. 26 In our series, with a lower dose of pilocarpine, pain was reported in 3.8% of the patients.
Mean baseline Jaeger notation improved from 5.84 +/-1.39 to 2.53 +/-1.71 (p ≤ 0.0001) one hour after the compound instillation, a gain of 3.30 +/-1.40 SD (0 to 6). Twenty-five (96.1%) patients gained one or more lines of UNVA. One patient loss 2 lines (3.8%). 96.1% of patients gained at least 1 line of UNVA one hour after drop instillation. Nine (7.6%) patients did not improve their UNVA with their compound compared with 1 patient (3.8%) in this study. One patient (3.8%) presented headache in our study.
The mean baseline photopic pupil diameter was 3.69 mm +/- 0.67 (range, 2.5 to 5). One hour after PBO instillation, the pupil diameter was 2.72 mm +/-0.52 (range 2 to 4) (p ≤ 0.000). The mean baseline scotopic pupil diameter was 4.61 mm +/-0.78 (range, 3 to 6). One hour after PBO instillation, the pupil diameter was 2.36 mm +/- 0.53 (range 2 to 4) (p ≤ 0.000). There was a significant contraction of the pupil due to the combined effect in both photopic and scotopic conditions of this compound.
Giovanna Benozzi reports in 2020 a retrospective series from 1 to 8 years of follow-up of 910 presbyopic individuals. The most frequent side effects were dim vision in 246 individuals (26%), headache in 119 individuals (12.9%), and ocular surface burning in 86 individuals (9.3%). 27 Although ours is a small population series, one patient reported dim vision (3.8%), and one patient reported headache (3.8%). One patient reported no improvement in near vision (3.8%), and one patient reported hyaline rhinorrhea lasting 30 minutes after drop instillation. Even with a small dose of pilocarpine, adverse reactions can be seen in sensitive individuals. Hyperemia was not reported in any of our patients in this series.
The combination of low-dose pilocarpine, a muscarinic parasympathomimetic, acting on receptors at the iris sphincter and the ciliary muscle, with brimonidine and oxymetazoline at low doses has a synergic effect, improving UNVA one hour after drop instillation. Brimonidine acts at the alpha 2 receptor of the iris dilator muscle, inhibiting its function and inducing indirect miosis. Combining those agents to induce myosis gave us the rationale to lower the concentration to achieve a similar result and avoid side effects such as pain, discomfort and dim vision. We believe that lowering the pilocarpine dose avoids ciliary muscle spasm and related pain and induces myopia, affecting distance vision and eye redness. Only one of our patients reported blurry vision at distance and lost lines of UDVA fully recovering after ceasing the effect of the compound. Oxymetazoline, an alpha 1 and partial alpha 2 imidazolic agonist, has a mydriatic effect. We believe that low concentrations slightly oppose the action of pilocarpine and brimonidine, hence avoiding spasm of the iris sphincter and allowing pupil movement. 28
This novel combination of pilocarpine, brimonidine and oxymetazoline in low doses has a synergistic effect, improving near vision in presbyopic patients and achieving at least up to 3.73 lines of near vision gain on the Jaeger notation at least one hour after instillation. This compound has the potential to mitigate the effects of presbyopia in healthy individuals. Further studies are being designed to document the long-term effect of this compound in patients with presbyopia.