Humphrey Visual Field (HVF)

This is a test of a patient's peripheral vision (not central)
It is done annually for all Glaucoma patients and people receiving Plaquenil therapy
Also done for people undergoing Ptosis surgery
While looking straight ahead a a fixation light, there will be flashing white lights all around in the periphery. Some will be bright and some dim; that's the point. It is testing what you can see and where
When the patient sees the flashing lights, they click the button in their hand
It is important for the patient to focus on the fixation light at all times, and not move their eye around looking at the flashing lights. This will result in an inaccurate test!

Note

It is imperative that the patient is situated properly during the test and the lens is positioned properly (forehead touching the headrest and their head doesn't drift left or right)
Always remember we test one eye at a time! Remember to place an eye patch on the opposite eye when testing!

Types of HVFs used at HEA

24-2 SITA Standard

Most common type and used primarily for Glaucoma
Covers 24 degrees from central with 54 points
Can sometimes be used for Plaquenil screening (physician preference)

10-2 (2 kinds)

Focuses centrally on the Macula (high density in a small field)
Covers 10 degrees with 68 points that are 2 degrees apart
10-2 Plaquenil: The main test for patients taking Plaquenil
10-2 Macula: Good for early detection in Glaucoma & macular patients

30-2

Focusses on the broadest area of the retina
Covers 30 degrees from central with 76 points
Takes the longest but is the most comprehensive of all HVFs

Superior 36 Ptosis

Used for people undergoing Ptosis surgery
Tests a 36 degree area vertical to the plane of the fixation point
Do one test normally, and then again with their eyelids taped up
It tests the increase in vision gained with the lids taped up to justify the ptosis surgery being covered by insurance

But what do all these numbers mean???

The following is not required, but here if you want additional clarification

From a point of fixation, a normal eye can detect stimulus 120 degrees vertically, and almost 160 degrees horizontally

The first number of an HVF means how many degrees we are testing outward from the central point of fixation

For example: A 24-2 tests 24 degrees outwards from the central fixation point (48 degrees total)

The second number represents how the grid of points are aligned relative to the visual axis (in other words, how far apart they are spaced from on another)

1: the points are overlying the horizontal and vertical meridians (we never use 1. The points are too close to one another)
2: The grid of points straddle these meridians (we always use 2 as the stimuli are spaced much farther apart)

The sensitivity to stimulus decreases rapidly outside of the 10 degrees directly surrounding the point of fixation (macula)

SITA

Swedish Interactive Threshold Algorithm
An algorithm developed specifically for the HVF that estimates threshold values for each point based on responses to stimuli presented at that location

Examples

This is what the 24-2 analysis looks like
The black areas are areas of lost vision
What is the black area in this picture????????

Here is a 10-2
Remember, this tests the Macula, which is why you do not see a blind spot where the optic usually is on a wider field analysis

Superior 36 Ptosis
The black dots represent points that were missed
The left is normal, and right is with the lids taped up
Notice the increase in the superior visual field with the lid taped up!

Note:

For the best result, it is important to tell the patient to let their lids fall naturally and not try and lift them (when they are not taped up)

This is called a rim artifact / defect
This is what happens when the lens is too far away from the patient's eye, and/or their forehead is drifting away from the rest
This result in the rim of the lens is physically blocking the patients vision

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