Failed The Eye Test During A DUI Investigation? Here’s What It Really Means
Daytona Beach DUI Defense Lawyer
Retired Homicide Detective. Former DUI Investigator. Trial Attorney.
One of the most common concerns people have after a DUI arrest is:
“The officer said I failed the eye test. Does that mean I’m guilty?”
The answer is simple:
No.
Many people assume the “eye test” is a scientific test that conclusively proves intoxication.
It is not.
In most Florida DUI cases, the so-called “eye test” refers to the Horizontal Gaze Nystagmus Test (HGN), a field sobriety exercise used by police officers during DUI investigations.
The HGN test is not a breath test.
It is not a blood test.
It does not measure alcohol concentration.
And failing the test does not automatically mean you were impaired.
At the Law Offices of Patrick J. McGeehan, P.A., we carefully analyze HGN evidence in every DUI case.
Before becoming a lawyer, Patrick served as a police officer, DUI investigator, traffic homicide investigator, police instructor, and homicide detective.
He administered field sobriety exercises during his law enforcement career and later learned how to challenge them in court.
Today, he uses that experience to defend individuals charged with DUI throughout Daytona Beach, Volusia County, Flagler County, and throughout Florida.
What Is The DUI Eye Test?
The DUI eye test is commonly known as the Horizontal Gaze Nystagmus Test.
During the test, the officer asks the driver to:
- Stand still
- Keep their head stationary
- Follow an object with their eyes
The object may be:
- A pen
- A flashlight
- A finger
- Another visual stimulus
The officer then observes eye movements while moving the object from side to side.
Related Page:
What Is HGN?
What Does The Officer Mean By “Failed”?
Many people believe the HGN test produces a pass or fail score.
It does not.
Instead, officers are trained to look for specific observations known as “clues.”
The officer records how many clues they believe were present and then forms an opinion regarding possible impairment.
When an officer says someone “failed” the eye test, what they usually mean is:
The officer observed what they believed were enough clues to support further DUI investigation.
That is an opinion.
It is not proof of guilt.
The Eye Test Does Not Measure BAC
One of the biggest misconceptions about the HGN test is that it measures blood alcohol concentration.
It does not.
The test cannot tell an officer:
- Your BAC
- How many drinks you consumed
- Whether you were legally intoxicated
The officer is simply observing eye movements and drawing conclusions.
You Can “Fail” The Eye Test And Still Win Your DUI Case
Many people assume the case is over once the officer claims they failed the HGN test.
That is simply not true.
The HGN test is only one piece of evidence.
The State must still prove:
- Driving or actual physical control
- Impairment
- Lawful police procedures
- Reliable evidence
A DUI conviction requires much more than a single field sobriety exercise.
Medical Conditions Can Cause HGN Clues
One reason HGN evidence is frequently challenged is that many medical conditions can affect eye movements.
Examples include:
- Vertigo
- Inner ear disorders
- Concussions
- Brain injuries
- Eye disorders
- Neurological conditions
An officer may not know about these conditions during a roadside investigation.
As a result, perfectly innocent explanations may exist.
Fatigue Can Affect The Eye Test
Many DUI arrests occur late at night or early in the morning.
Drivers are often:
- Exhausted
- Sleep deprived
- Working long shifts
- Returning home from work
Fatigue may affect appearance, concentration, and eye behavior.
The officer’s interpretation may not always be correct.
Prescription Medications Can Affect Results
Certain medications may affect observations associated with HGN testing.
Examples include medications prescribed for:
- Anxiety
- Sleep disorders
- Pain management
- Muscle spasms
The existence of HGN clues does not automatically mean alcohol impairment.
Related Page:
DUI With Prescription Drugs
Marijuana Cases Present Additional Problems
Many marijuana DUI investigations involve discussions regarding HGN testing.
Questions frequently arise regarding:
- Whether marijuana affects eye movements
- Whether other substances were involved
- Whether the officer interpreted observations correctly
These cases often involve complicated scientific issues.
Related Page:
Marijuana DUI Defense
The Officer Might Have Administered The Test Incorrectly
The HGN test requires specific procedures.
Common problems include:
Moving The Stimulus Too Fast
Moving The Stimulus Too Slowly
Improper Positioning
Poor Lighting Conditions
Failure To Follow Standardized Procedures
Officer Observation Errors
Even small mistakes can affect the reliability of the results.
Body Camera Video Frequently Changes The Story
Many DUI reports contain statements such as:
“The defendant displayed six out of six clues.”
However, body camera footage often reveals important details that do not appear in the report.
Questions frequently include:
- Was the test administered properly?
- Did the officer follow training?
- Were instructions clear?
- Were distractions present?
Video evidence frequently becomes one of the most important parts of the defense.
The Officer’s Opinion Is Not The Same As Scientific Proof
Jurors are often surprised to learn that the HGN test does not produce scientific measurements.
The officer is not measuring:
- BAC
- Alcohol concentration
- Degree of intoxication
Instead, the officer is making observations and offering an opinion.
That opinion may be challenged.
Common Defenses When The Officer Claims You Failed The Eye Test
Every case is different.
Potential defenses may include:
Improper Administration
Medical Conditions
Prescription Medication Effects
Fatigue
Environmental Conditions
Lack Of Officer Training
Officer Misinterpretation
Constitutional Violations
The fact that an officer says you failed the eye test does not mean the case cannot be challenged.
Why DUI Lawyers Frequently Challenge HGN Evidence
HGN evidence is often one of the most vulnerable parts of a DUI investigation.
The test depends on:
- Human observation
- Proper training
- Proper administration
- Proper interpretation
Any weakness in those areas may affect reliability.
Related Page:
Can The HGN Test Be Wrong?
HGN Evidence And DUI Trials
Many DUI cases involving HGN ultimately come down to credibility.
Jurors often ask:
- Did the officer follow proper procedures?
- Is there another explanation?
- Can the officer’s conclusions be trusted?
These questions frequently become central issues at trial.
Related Page:
DUI Jury Trial Lawyer
Frequently Asked Questions
Does Failing The Eye Test Mean I Am Guilty?
No.
The HGN test is only one piece of evidence.
Can A Sober Person Fail The Eye Test?
Potentially.
Medical conditions, fatigue, and other factors may affect results.
Can Prescription Drugs Affect The Eye Test?
Yes.
Certain medications may influence observations associated with HGN testing.
Can HGN Evidence Be Challenged?
Absolutely.
The test is frequently challenged in DUI cases.
Can A DUI Be Won Even If The Officer Says I Failed The HGN Test?
Yes.
Many DUI defenses focus on weaknesses in HGN evidence and other parts of the investigation.
Why Clients Choose Patrick J. McGeehan
Many attorneys handle DUI cases.
Few have administered HGN testing before becoming lawyers.
Patrick’s background includes:
- Former DUI Investigator
- Police Officer
- Police Instructor
- Retired Traffic Homicide Investigator
- Retired Homicide Detective
- Trial Attorney
Most attorneys learn HGN testing from police reports and courtroom testimony.
Patrick administered field sobriety exercises himself and later learned how to challenge them.
That experience provides valuable insight when evaluating DUI evidence.
Contact A Daytona Beach DUI Defense Lawyer
If the officer claims you failed the eye test, do not assume the case is over.
The officer’s opinion is not the final word.
The facts matter.
The science matters.
The evidence matters.
The defense matters.
Contact the Law Offices of Patrick J. McGeehan, P.A. today to schedule a consultation and learn how an experienced Daytona Beach DUI lawyer can evaluate the evidence and help protect your rights and your future.
Resources:
Leaving the Scene of an Accident With a Death
Fatal Crash Investigations in Florida