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The following is a summary of “Reversal of Pharmacologically Induced Mydriasis with Phentolamine Ophthalmic Solution,” published in the September 2024 issue of Ophthalmology by Pepose et al. 

Researchers conducted 2 prospective Phase 3 clinical trials to assess the efficacy and safety of 0.75% phentolamine ophthalmic solution (POS) in reversing pharmacologically induced mydriasis. 

The study included 553 healthy participants (ages 12 to 80). Participants were randomly assigned to receive either POS or placebo eye drops in a 1:1 (MIRA-2) and 2:1 (MIRA-3) ratio. Mydriasis was induced using [2.5% phenylephrine, 1% tropicamide, or Paremyd (1% hydroxyamphetamine / 0.25% tropicamide)], and POS or placebo was administered 1 hour later.  

The main outcome was the percentage of participants returning to ≤0.2 mm greater than baseline pupil diameter at 90 minutes, with safety measured by treatment-emergent adverse events, including conjunctival hyperemia. 

The results showed that a significantly higher percentage of subjects treated with POS experienced a reversal of mydriasis at 90 minutes (48.9% vs 6.6% for MIRA-2, P <0.0001; 58% vs 6% for MIRA-3, P<0.0001) and as early as 60 minutes (24.5% vs 5.5% for MIRA-2, P <0.0003; 42% vs 2% for MIRA-3, P <0.0001) compared to placebo. Additionally, 28% to 34% of placebo-treated subjects had not returned to baseline pupil diameter at 24 hours compared to 8% to 11% treated with POS (P <0.0001). 

The study concluded that POS rapidly and effectively reverses pharmacologically induced mydriasis with a favorable safety profile. 

Source: aaojournal.org/article/S0161-6420(24)00558-X/fulltext