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Water-drinking test in patients with primary open-angle glaucoma while treated with different topical medications
Michele Vetrugno1, Dario Sisto, Tiziana Trabucco
1Department of Ophthalmology and Otorhinolaringology, University of Bari, Bari, Italy. glaucoma@oftalmo.uniba.it
Summary
Glaucoma medications vary in their ability to stabilize intra-ocular pressure (IOP) during a water-drinking test. Medications enhancing outflow, like bimatoprost, show better IOP control compared to those reducing fluid production.
Area of Science:
- Ophthalmology
- Glaucoma Research
- Pharmacology
Background:
- Intra-ocular pressure (IOP) control is crucial for managing glaucoma.
- Water ingestion can induce osmotic variations, leading to IOP fluctuations.
- The water-drinking test (WDT) assesses IOP response to osmotic challenges.
Purpose of the Study:
- To evaluate the efficacy of different IOP-lowering medications in stabilizing IOP during the WDT in primary open-angle glaucoma (POAG) patients.
- To compare the effects of drugs with distinct mechanisms of action on IOP fluctuations.
Main Methods:
- 280 POAG patients were divided into 7 medication groups (timolol, dorzolamide, brinzolamide, travoprost, latanoprost, bimatoprost, brimonidine).
- Patients underwent a standardized WDT (1000 mL water in 10 min) after baseline IOP measurement.
- IOP was monitored at 15-minute intervals until return to baseline, measuring IOP peak, percentage increase, and time to return.
Main Results:
- Timolol resulted in the highest mean IOP peak and the greatest IOP percentage increase.
- Bimatoprost demonstrated a significantly lower IOP percentage increase compared to latanoprost, dorzolamide, and brinzolamide.
- The duration of IOP elevation was shortest with bimatoprost and longest with timolol.
Conclusions:
- Topical medications that enhance aqueous humor outflow (e.g., bimatoprost, latanoprost, travoprost, brimonidine) appear to offer superior IOP stabilization during WDT compared to medications that reduce inflow.
- Drugs like timolol and topical carbonic anhydrase inhibitors may be less effective in preventing IOP spikes under osmotic stress.