What is the effect called when unilateral use of Timolol reduces IOP in the contralateral eye?

The phenomenon where unilateral administration of Timolol leads to a reduction in intraocular pressure (IOP) in the contralateral eye is referred to as the crossover effect. This effect occurs due to the systemic absorption of the medication, which can then affect both eyes even though the treatment was applied to only one.

Timolol is a non-selective beta-blocker commonly used in treating glaucoma. When applied topically, it can lower IOP effectively in the treated eye, but because of its systemic effects, it may also lead to reduced IOP in the untreated eye. This observation highlights the interconnected nature of ocular physiology and the potential systemic impact of topical ocular medications.

Understanding the crossover effect is important for clinicians as it illustrates how therapies can influence ocular pressure beyond their intended target, potentially affecting treatment outcomes and patient monitoring strategies.