How do you check Goldmann tonometer calibration?

Set the measurement dial to positions 0, 2, and 6 (corresponding to 0, 20, and 60 mmHg). At each setting, verify that the feeler arm moves freely and settles at the correct position within +/- 0.5 scale divisions. If readings fall outside this tolerance, the instrument needs professional servicing. This check should be performed daily as part of the morning routine and documented in a maintenance log.

What should you do when an instrument gives inconsistent readings?

First, try basic troubleshooting: clean the optics and contact surfaces, check the power source and batteries, verify calibration, and restart the device. If the problem persists, document the issue (instrument, symptom, onset, troubleshooting attempted), tag the instrument as out of service, notify the office manager or service provider, and record the service request in the maintenance log. Never continue using an instrument that gives inconsistent results.

What is preventive maintenance for ophthalmic equipment?

Preventive maintenance is the scheduled routine of cleaning, inspecting, and servicing equipment before problems develop. Daily tasks include cleaning patient-contact surfaces, checking power-on functionality, and verifying calibration. Monthly and quarterly tasks include deep cleaning optics, checking backup batteries, reviewing maintenance logs for patterns, and scheduling manufacturer-recommended professional servicing. Proper preventive maintenance extends instrument life and ensures measurement accuracy.

Equipment Troubleshooting: COA Exam Guide

Why Equipment Troubleshooting Skills Matter

Ophthalmic instruments are precision devices that provide the diagnostic measurements physicians rely on for clinical decisions. When equipment malfunctions or falls out of calibration, patient care suffers through inaccurate measurements, delayed appointments, and potentially incorrect treatment decisions. As a COA, you are often the first person to notice when something is not working correctly, and your ability to identify and resolve basic issues keeps the clinic running efficiently.

Calibration Verification

Calibration ensures that an instrument measures accurately. Think of calibrating a scale before weighing ingredients for a recipe. If the scale is off by even a small amount, the final product will not turn out correctly. The same principle applies to ophthalmic instruments.

Tonometer Calibration

The Goldmann applanation tonometer should be checked regularly using its built-in calibration mechanism:

Set the measurement dial to 0, 2, and 6 (representing 0, 20, and 60 mmHg)
At each setting, check that the feeler arm moves freely and settles at the correct position
The dial should read within +/- 0.5 scale divisions of the target
If readings fall outside this range, the instrument needs professional servicing

Make tonometer calibration check part of your morning routine. It takes less than a minute and catches drift before it affects patient measurements. Document each calibration check with the date and result in a maintenance log.

Lensometer Calibration

Verify the lensometer reads zero (plano) when no lens is in the stage. If the lensometer consistently reads a small plus or minus value with an empty stage, it needs adjustment or professional service.

Autorefractor/Keratometer

Many autorefractors and keratometers include a built-in calibration test eye or reference sphere. Run the calibration check against this reference and verify the readings match the known values within acceptable tolerance.

Common Malfunctions and Solutions

Problem	Possible Cause	Basic Troubleshooting
Inconsistent tonometer readings	Dirty prism, low battery, calibration drift	Clean prism, replace battery, check calibration
Autorefractor won't capture	Dirty optics, patient alignment, software glitch	Clean lens surfaces, reposition patient, restart device
Slit lamp bulb dim or flickering	Bulb aging, voltage regulator issue	Replace bulb, check power settings
Lensometer fuzzy target	Dirty optics, eyepiece out of focus	Clean optics, adjust eyepiece focus for user
OCT poor signal quality	Dirty lens, media opacity, alignment	Clean scan head, optimize patient positioning
Visual field test unreliable	Patient fatigue, incorrect parameters	Rest patient, verify test settings match order

Malfunction Reporting and Documentation

When you encounter an equipment issue that you cannot resolve with basic troubleshooting:

Document the problem clearly: what instrument, what symptom, when it started, what you tried
Tag the instrument as out of service to prevent others from using it
Notify the appropriate person (office manager, biomedical engineering, manufacturer)
Record the service call, repair date, and resolution in the maintenance log

Continuing to use an instrument that gives inconsistent readings because "it still kind of works." Inaccurate measurements can lead to incorrect clinical decisions. If you suspect calibration drift or malfunction, take the instrument out of service until it is verified.

Preventive Maintenance

Preventive maintenance is the scheduled routine of cleaning, checking, and servicing equipment before problems develop. A well-maintained instrument lasts longer, performs more reliably, and reduces unexpected downtime.

Daily maintenance tasks:

Clean all patient-contact surfaces
Check that instruments power on correctly
Verify calibration on tonometers and lensometers
Inspect cords and cables for damage

Monthly/quarterly tasks:

Deep clean optics and housings
Check backup batteries
Review maintenance log for recurring issues
Schedule professional servicing per manufacturer recommendations

A maintenance log is not just good practice; it is often required for accreditation and compliance. Document all calibration checks, repairs, and professional service visits with dates and outcomes. This log demonstrates that the practice maintains its equipment to appropriate standards.

Error Codes and User Manuals

Modern ophthalmic instruments display error codes when something goes wrong. Keep user manuals accessible (physical or digital) for quick reference. Many manufacturers also provide online support portals and phone helplines for troubleshooting assistance. Familiarize yourself with the most common error codes for the instruments you use daily.

Key Takeaways

Check tonometer calibration daily at the 0, 2, and 6 settings
Verify lensometer reads plano with an empty stage
Clean instrument optics as a first troubleshooting step for many issues
Remove malfunctioning instruments from service until verified or repaired
Document all maintenance, calibration checks, and service calls in a log
Preventive maintenance reduces unexpected downtime and improves measurement accuracy