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Visual Field Basics

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vishal patel

on 23 June 2014

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Transcript of Visual Field Basics

Visual Field Basics
Visual Fields
Important diagnostic tool in the evaluation of patients with many different types of pathologies.

What are some common diseases where VF testing can be a vital diagnostic tool?

Visual Pathway
Test Reliability
Reliability indices
High Fixation Losses (>15%) = unreliable
High False Positives (>10%) = unreliable
The field may look normal
"trigger happy"
High False Negatives (>10%) = unreliable
Did not press button when should have
Not paying good attention
The End
Types of visual field loss
Focal area of decrease perception surrounded by a more sensitive area.
Area of decrease sensitivity without a normal surround
Loss in a half-field
Complete (Must indicate affected side)
"Left Homonymous Hemianopa"
"Nasal Step"

Gray Scale
Easy plot to use for quick identification of potential scotomas and depression.
Look at only the gray scale can lead to inaccurate interpretation
Must also interpret
total deviation
pattern deviation

Total Deviation
Key graph that can be best assessed by using the probability plots with the shaded boxes at each test location, and not the numerical dB plot.
Darkly shaded squares are more abnormal then lightly shaded squares
Can be used to pick up corneal or lenticular opacities
Pattern Deviation
Designed to highlight localized defects by “removing” generalized visual field loss (likely due to a cataract).

Global Indices
Mean Deviation (MD
0dB to -2dB = Stable
>-2dB = Worsening of GENERAL field loss
Pattern Standard Deviation (PSD)
best quantifies the amount of loss as well any progression of glaucoma in the early stages.
Slow "peripheral" vision loss
24-2 Sita Standard

Unilateral or Bilateral
CVA (Stroke)
Homonymous Hemianopias
30-2 Sita Standard
Optic Neuropathy
Anterior Ischemic Optic Neuropathy (AION)
30-2 or 24-2 sita standard
Inferior altitudinal defect (Pathognomonic)
What do HVF numbers mean?
tests points 10° around the center vision (fovea)
tests points 24° around the center vision
tests points 30° around the center vision
Protocol 2 tests points on either side of the horizontal and vertical axis
HVF 10-2
Plaquenil toxicity
Macular disease
End stage glaucoma
HVF 24-2
Standard for mild to moderate Glaucoma
Glaucoma suspect
HVF 30-2
History of CVA (Stroke)
Brain tumors
Pituitary Adenoma
SF or SS
more variability is allowed between the repeated measurements, which allows for a faster test
70% less time vs. full threshold
only small differences are acceptable
standard for glaucoma testing

50% less time vs. full threshold

Macular Disease
Plaquenil toxicity
Macular scar
End stage glaucoma
10-2 sita standard
Vishal Patel OD
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