Pilocarpine 0.4%: Significant decrease in pupillary diameter in presbyopic patients

Researchers from the Bascom Palmer Eye Institute in Miami found that instillation of pilocarpine hydrochloride ophthalmic solution 0.4% (Qlosi; Orasis Pharmaceuticals, Ltd) resulted in a significant reduction in pupillary diameter with minimal impact on lens thickness and ciliary muscle accommodation in presbyopic eyes. Florence Cabot, MD, reported the study results at the Hawaiian Eye and Retina 2026 meeting on January 17 to 23 on the Big Island. She is a Research Associate at Bascom Palmer Eye Institute, University of Miami Miller School of Medicine in Florida.

Cabot and her colleagues conducted a prospective, single-center, head-to-head study to determine the effect of pilocarpine 0.4% on pupillary size, lens, and ciliary muscle responses in individuals with presbyopia. The patients, aged 45 to 64 years and with spherical equivalent values ranging from −4.00 to +2.00 D, received pilocarpine 2.0%, pilocarpine 0.4%, or balanced saline solution (BSS).

The patients also underwent anterior segment optical coherence tomography at baseline and 1 hour after instillation of the drops. The high-resolution images were recorded and analyzed to assess how each treatment responded to the patients’ visual demands by evaluating ciliary muscle movement, pupil diameter, and lens thickness.

What effects of pilocarpine did investigators observe in the participants?

The study included 10 participants with a mean age of 51.5 years (range, 46.3-64.3). The primary finding was that pilocarpine 0.4% significantly reduced the pupillary diameter compared with BSS (the control) (P < .05), but the lens thickness and the ciliary muscle response did not change significantly.

Cabot enumerated the key points of the study on the effects of treatments on the ocular tissues as follows: “Pilocarpine 2% showed a statistically significant change in the ciliary muscle thickness at near that was not observed in the BSS and Qlosi groups, pilocarpine had a dose-dependent effect on the pupillary diameter, and pilocarpine 2% showed a residual lens accommodative effect not seen in the BSS and Qlosi groups,” she reported.

Commenting on the concentration-dependent effects of pilocarpine in the eye and their relevance, Cabot said, “These new data prove that Qlosi is truly pupil selective. In imaging studies performed at the Bascom Palmer Eye Institute, Qlosi, 0.4% pilocarpine, showed ciliary muscle movement similar to the BSS control, [whereas] the high concentration of 2% pilocarpine showed significant ciliary muscle contraction that was not seen in the other 2 groups. Low-dose pilocarpine has a concentration-dependent response, proving that the formulation truly matters. Low-dose Qlosi was truly designed with the presbyopic patient in mind.”