Certified Ophthalmic Medical Technologist (COMT) Practice Exam 2025 – Comprehensive All-in-One Guide to Success

In the context of tonometry, particularly when using a Goldmann applanation tonometer, it is important to understand how the device operates and the principles behind measuring intraocular pressure (IOP). The Goldmann tonometer measures the pressure of the eye by flattening a small area of the cornea. The amount of aqueous humor that is displaced during this applanation process is what the tonometer uses to calculate intraocular pressure.

The correct volume of aqueous humor displaced is 0.5 microliters. This specific volume is significant because it reflects the delicate balance of counteracting the pressure exerted by the device and the pressure within the eye itself. A total displacement of this volume allows for an accurate assessment of IOP, adhering to the principles of applanation tonometry where the degree of flattening is directly related to the intraocular pressure of the eye.

Understanding the significance of this displaced volume is crucial for ophthalmic technicians, as it assists in interpreting the results of the tonometry correctly. Other volumes like 0.1, 1.0, or 1.5 microliters do not align with the established parameters of measurement for standard Goldmann tonometry and could lead to inaccurate assessments if used in practice. Thus, recognizing