Certified Ophthalmic Assistant Practice Exam

Which drug is commonly used for application tonometry?

1. Proparacaine

2. Cyclopentolate

3. Timolol

4. Phenylephrine

The correct answer is: Proparacaine

Proparacaine is commonly used for application tonometry because it is a topical anesthetic that numbs the surface of the eye. When performing tonometry, it is essential to eliminate any discomfort that the patient might feel during the procedure, especially since the probe used to measure intraocular pressure can cause sensations of pressure or touch on the cornea. Proparacaine works rapidly to provide anesthesia, facilitating a smoother and more comfortable experience for the patient. The other choices, while they have their therapeutic uses, are not suitable for this specific application. Cyclopentolate is primarily used for pupil dilation, Timolol is a beta-blocker used to lower intraocular pressure in conditions like glaucoma, and Phenylephrine is used to dilate the pupil and as a vasoconstrictor. None of these drugs serve the purpose of providing immediate surface anesthesia, which is crucial for application tonometry.