Purpose: The purpose of the study was to assess the effect of ibopamine (3,4 di-isobutyrrylester of N-methyldopamine), a D1-dopamine agonist, on intraocular pressure (IOP) in offspring of parents with primary openangle glaucoma as a consequence of outflow structures impairment.
Materials and methods: We included participants aged between 8 and 40 years: group 1, 163 offspring of at least 1 parent with primary openangle glaucoma with normal IOP and without glaucomatous damages; group 2, 108 offspring of healthy parents (without history or existing glaucoma). Ibopamine test was performed by instilling 2 drops, 5 minutes apart, in both eyes followed by repeated IOP measurements over a 45-minute period. The test is considered positive if there is an IOP increase of ≥3 mm Hg 45 minutes after instillation.
Results: Baseline IOP before the test was 15.73±2.31 and 15.31±1.86 mm Hg in groups 1 and 2, respectively. Test was positive in 44.33% of cases in group 1 with a mean increase in IOP of 5.57 mm Hg (P<0.001), whereas in all participants of group 2 the test was negative with even 1 to 2 mm Hg IOP reduction.
Conclusions: D1-dopaminergic stimulation due to ibopamine increases IOP as a result of increased production of the aqueous humor in participants with an impaired outflow. The study showed that offspring of at least 1 parent with primary openangle glaucoma--offspring without glaucomatous damages--show an increase of IOP after ibopamine administration, which signifies an impaired function of outflow structures and, therefore, a predisposition to intraocular hypertension and possible glaucoma.