Related Experiment Video
Updated: Mar 13, 2026

Trabecular Meshwork Response to Pressure Elevation in the Living Human Eye
Published on: June 20, 2015
Pharmacodynamic profile of mydriatic agents delivered by ocular piezo-ejection microdosing compared with conventional
Tsontcho Ianchulev1, Arturo Chayet2, Malik Kahook3
1Department of Ophthalmology, University of California at San Francisco, 707 Oregon Ave, San Mateo, CA 94402, USA.
Aim:
Eyedroppers deliver medication volumes exceeding conjunctival absorptive capacity, causing spillage and risking ocular/systemic complications. We evaluated piezoelectric microdosing. Results/methodology: Subjects (n = 102) received precision microdroplet delivery of phenylephrine (2.5%) and tropicamide (1.0%): 1 × 1.5 μl, 1 × 6 μl or 2 × 3 μl of each (randomized 1:1:1), into one eye. Contralateral eyes received eyedropper doses of both drugs. Outcomes were pupil dilation (0-60 min) and patient satisfaction. Six-microliter microdosing achieved comparable, and 2 × 3 μl met/exceeded dilation speed and magnitude versus eyedropper. Separately, participants preferred piezoelectric saline self-delivery to eyedroppers, reporting better head-positioning comfort, reduced tearing/overflow and increased likelihood of adhering to ocular medication regimens.
Conclusion:
Piezoelectric microdosing achieves comparable effects as eyedroppers delivering 4-17-fold larger doses. Microdosing may enhance patient adherence to ocular medication regimens while minimizing side effects.
Related Concept Videos
Ophthalmic Drug Delivery Systems
Open Angle Glaucoma: Treatment
Drugs such as carbonic anhydrase inhibitors, α2- and...
Drug Delivery: Miscellaneous Routes
Oral inhalation and nasal sprays swiftly transfer drugs across the respiratory epithelium's mucosal layer. Inhaled glucocorticoids and bronchodilators directly target lung conditions such as asthma, while fluticasone nasal spray mitigates allergic rhinitis.
Transdermal patches transport drugs...
Indirect-Acting Cholinergic Agonists: Pharmacokinetics
Reversible agents containing quaternary amines, such as neostigmine and edrophonium, are not easily absorbed orally because they...
Pharmacodynamic Models: Direct Effect Model and Indirect Response Model
Direct-Acting Cholinergic Agonists: Therapeutic Uses

