A recent study investigated the efficacy and safety of timolol maleate 0.5% microdrops delivered using the Nanodropper Adaptor to lower intraocular pressure in patients diagnosed with open-angle glaucoma and ocular hypertension. The trial, conducted at Aravind Eye Hospitals in India, compared the efficacy and safety of microdrops with conventional eyedrops.
IOP remains the only known modifiable risk factor in glaucoma and can be lowered using topical eyedrops. However, the investigators noted several issues with adherence to drops among patients, including medication-related adverse events, difficulty obtaining medications, prohibitive costs, and limited efficacy related to drop size. “The human eye can absorb only 7 to 10 μl of exogenous fluid, yet most glaucoma medication bottles dispense drops that range from 25 to 60 μl,” the authors note in the article published in Ophthalmology. The extra medication drains through the nasolacrimal ducts and is absorbed through the nasal mucosa. In cases where IOP-lowering topical beta-blockers are used, for example, this drainage can lead to decreased heart rate, decreased blood pressure, and irregular pulse.
Microdrops have been proposed as an alternative to larger drop sizes, but they have only recently become commercially available. The Nanodropper Adapter, which is compatible with existing standard eyedrop bottles, is a delivery mechanism that produces microdrops. A previous study shows, “microdrops delivered with the adaptor provided noninferior mydriasis relative to conventional drops in a pediatric population.” In addition to the potential increased efficacy of microdrops, the researchers note that the significant increase in the number of drops per bottle could reduce the cost of therapy and contribute to improved patient adherence to their medication.
The study sought to determine whether 12.5 μl microdrops of timolol maleate 0.5% lowered IOP as effectively as 28 μl conventional drops via a randomized, controlled trial involving 150 patients diagnosed with open-angle glaucoma or ocular hypertension. Patients were divided into two groups: one received microdrops via the Nanodropper Adaptor and the other received conventional eyedrops.
Both microdrops and conventional drops significantly reduced IOP. The largest reduction was observed 5 hours after administration, with microdrops reducing IOP by 7.78 mmHg and conventional drops by 8.53 mmHg. Microdrops also had a less pronounced effect on resting heart rate compared with conventional drops, suggesting reduced systemic absorption. Participants in the microdrop group reported higher satisfaction with the treatment due to reduced ocular surface irritation and less medication waste.
No significant adverse events were noted, and both methods were deemed safe for long-term use. “Overall, the results of this study present the adaptor as a tool to optimize the topical management of ophthalmic conditions,” the investigators conclude.
A full list of author disclosures can be found in the published research.