Transcript Slide 1
PERFORMING RELIABLE VISUAL FIELDS
NOA Fall Conference Presented by Jill Luebbert, CPOT, ABOC
What are “Visual Fields”
A test?
A view of the plains of Nebraska?
“the area or extent of physical space visible to the eye in a given position
How much can we see?
Monocular visual fields usually measure 60 degrees superior 75 degrees inferior 105 degrees temporal 60 degrees nasal
Making a map
a.k.a.
Performing Visual Fields
Meridians and Quadrants
Horizontal meridian Vertical meridian Quadrants Circles of eccentricity
Two methods of presenting Visual Fields
Kinetic Static
Kinetic
Target in motion moved from non-seeing to seeing
Static
Stationary target Threshold or suprathreshold
Terminology
What are they talking about?
Terms used
Perimetry
Visual field testing with eye located at the center of a curved instrument
Campimetry
Visual field testing eye located a specified distance from a flat surface
Scotoma
Vision entirely absent
Blind Spot (natural)
Approximately 15 degrees temporal to fixation (Optic Nerve)
Isopter
Boundary mapped for a particular stimulus size and intensity Iso = equal opter = sight
Decibel
Relative unit, 1/10 log unit
Threshold
Every test point is evaluated by bracketing or staircase method
Suprathreshold
Target value assumed to be above threshold value for all points
False negative
Patient does not respond when a maximally bring stimulus is present at a point previously found to be normal
False positive
Patient responds when no stimulus was present
Grayscale
To be used for patient education – Represents tested points, which have been assigned value
Mean Deviation
Difference in decibels between “normal” and patient’s hill of vision
Pattern Standard Deviation
The measurement of the degree which the shape of patient’s measured “hill” of vision departs from normal
Short Term Fluctuation
A measurement of the degree of variation of threshold during the test
Types of Visual Fields
Confrontation Harrington Flocks (Burton) Screener Tangent Screen
Arc Perimeter
Amsler Grid
Frequency Doubling Technology FDT
Goldmann introduced in 1945
Auto Perimeters
Humphrey (Carl Zeiss Meditec) Octopus (Haag-Steit)
What is the “hill of vision”?
Why do we perform Visual Fields?
To monitor area of vision utilized Monitor diseases Glaucoma Macular Degeneration Stroke
The technician’s responsibility
To be comfortable and knowledgeable with the instrument used To perform accurate and reliable visual fields To perform repeatable visual fields To accurately gather diagnostic data To keep the patient as comfortable and relaxed as possible This is not a speed test
Setting up and Preparing
Data entry can be completed before the patient sits down Choose the correct test Set variables
Setting up
Choose the pre-determined test Variables Color Fluctuation Blind Spot Size Test Speed
Setting Up
Enter Patient Information Spell the name same format every time All caps or upper and lower case Last name first or first name fist Middle initial with period or without period Date of Birth Vision Acuities Lens Used Pupil Size
Preparing the patient
Introduce yourself Acknowledge them by their name Comfortable atmosphere Explanation of what to expect What to see or not to see How long to expect Breaks??
Ready to start
Clean the instrument New chin cover sheet Give them the controller Occlude non-testing eye
Positioning
Make this as comfortable as possible Adjust the instrument height Adjust the chin rest height Chin and forehead firmly in place Keep teeth clenched together Adjust lens holder Not too close or too far away
Ready???
Verify the patient is in position Give them a short test run first All OK??
Ready Set Start
Now what?
MONITOR DO NOT LEAVE THE PATIENT Monitor fixation Monitor attentiveness Is the patient staying securely to forehead rest and in chin rest
Remember
Restart if necessary It is important to achieve reliable results Is the patient staying attentive Take breaks as you judge necessary This is not a race
Finished
Are you performing the same test on the other eye?
Take a short break between Let the patient stretch their fingers, neck Occlude next eye Give the patient the control Any questions???
Position
Keep a watchful eye
Monitor Fixation Patient attentiveness
Testing Complete
Save results Return instrument control Return testing lens Return occluder Print or send results to correct station Note any observations patient restless, etc Escort patient to next station
“How did I do?”
Do not share results Let the patient know they provided lots of data for the doctor to review The doctor will visit with them regarding the results
Congratulations on performing
Thorough
Accurate
Repeatable
Visual Fields
Enjoy Nebraska Optometric Conference Experience Jill J Luebbert, CPOT, ABOC [email protected]
www.jjlconsulting.com
Luebbert Consulting & Training