COT Ophthalmic Instrumentation and Equipment Maintenance

Question 1

A Goldmann applanation tonometer is being calibrated using the calibration bar. At the 20 mmHg position, a reading of 22 mmHg is obtained. What action should be taken?

Accepted Answer

Remove the instrument from service and schedule repair

Answer

The acceptable calibration tolerance for the Goldmann applanation tonometer is ±0.5 mmHg. A deviation of 2 mmHg at the 20 mmHg check point exceeds this tolerance, meaning the instrument must be taken out of service and sent for calibration or repair before further clinical use.

Question 2

Which disinfection method is recommended between patients for a Goldmann applanation tonometer prism to prevent transmission of adenovirus and other pathogens?

Accepted Answer

Wipe with 70% isopropyl alcohol and allow to air dry for at least 5 minutes

Answer

The CDC and JCAHPO recommend disinfecting tonometer tips between patients by wiping with 70% isopropyl alcohol and allowing a contact time of at least 5 minutes before reuse. Autoclaving damages the prism coating, and saline alone does not adequately disinfect.

Question 3

A keratometer is producing mire images that appear distorted and asymmetric even after lens cleaning. The MOST appropriate next step is to:

Accepted Answer

Verify accuracy by measuring a steel calibration sphere of known radius

Answer

When a keratometer produces suspect or distorted readings, the standard troubleshooting step is to measure a steel calibration sphere of known radius to verify whether the instrument is producing accurate values. This confirms whether the issue is instrument calibration or corneal irregularity.

Question 4

When cleaning the objective lens of a slit lamp biomicroscope, the correct technique is to:

Accepted Answer

Use a lens-cleaning solution with a lint-free cloth, wiping gently from center outward

Answer

Optical surfaces should be cleaned using an appropriate lens-cleaning solution and a lint-free cloth, wiping from center outward to avoid dragging debris across the optical surface. Isopropyl alcohol can damage coatings, and dry or abrasive materials can scratch the lens.

Question 5

Which sterilization method is MOST appropriate for ophthalmic surgical instruments with heat-sensitive components?

Accepted Answer

Ethylene oxide (EtO) gas sterilization

Answer

Ethylene oxide (EtO) gas sterilization achieves full sterilization at low temperatures (37–63°C), making it safe for heat-sensitive materials such as plastics, rubber, and certain instrument components that would be damaged by autoclaving or dry heat. Boiling does not achieve sterilization.

COT - Certified Ophthalmic Technician Practice Test

COT - Certified Ophthalmic Technician Practice Test

COT Ophthalmic Instrumentation and Equipment Maintenance