What is the most common pattern of visual field loss in glaucoma?

What is the most common pattern of visual field loss in glaucoma?

Typical glaucomatous visual field loss is characterized by arcuate defects, nasal steps, and other patterns corresponding to the course of retinal nerve fibers that respect the nasal horizontal meridian and usually spare the visual field center.

What visual field defects indicate glaucoma?

Relatively specific glaucomatous visual field defects (see Figure ​3 for examples) include:

  • a nasal step defect obeying the horizontal meridian.
  • a temporal wedge defect.
  • the classic arcuate defect, which is a comma-shaped extension of the blind spot.
  • a paracentral defect 10–20° from the blind spot.

How do you identify visual field defects?

Visual fields are frequently evaluated by simply covering one eye and asking the patient to look straight ahead while using peripheral vision to identify an object, or the number of fingers shown by the examiner. The field is often tested at only four locations, which is sensitive only for large field defects.

What is visual field progression in glaucoma?

The glaucoma progression analysis (GPA) was devised for this purpose. It is based on pattern deviation, defined as the deviation from age-corrected values adjusted for the general height (GH) of the visual field. The GH is estimated from the relative depression of the 15th percentile of the total deviation values.

Why is peripheral vision loss first in glaucoma?

On average, we have 1 million retinal ganglion cells in each eye. Glaucoma damages the retinal ganglion cells and eventually causes them to die. Also, glaucoma typically damages the retinal ganglion cells in a pattern in which the peripheral (side) vision is affected first.

What testing method is used to rapidly determine the presence or absence of a field defect?

Threshold static perimetry is generally done using automated equipment. It is used for rapid screening and follow-up of diseases involving deficits such as scotomas, loss of peripheral vision and more subtle vision loss.

How do you test field of vision?

You wear a blindfold while your doctor holds up different fingers in your peripheral vision and asks what you see. Automated static perimetry test. This test is much more detailed. Your doctor uses it to make a complete image of your field of vision.

What is Anderson criteria?

Andersen’s criteria for glaucomatous field defect: These criteria (in relation to a Humphrey printout only) are helpful in the diagnosis of early glaucoma and are as follows: Abnormal GHT. Three or more nonedge points of the 30-2 printout, contiguous and with a P < 5%, out of which at least 1 has a P < 1%

What is Pattern Deviation in visual field?

Pattern standard deviation (PSD) measures irregularity by summing the absolute value of the difference between the threshold value for each point and the average visual field sensitivity at each point (equal to the normal value for each point + the MD).

How do you know if you are losing peripheral vision?

Peripheral vision loss (PVL) occurs when you can’t see objects unless they’re right in front of you. This is also known as tunnel vision. Loss of side vision can create obstacles in your daily life, often impacting your overall orientation, how you get around, and how well you see at night.

How does glaucoma affect peripheral vision?

Glaucoma: This disease is caused by the buildup of fluid and pressure in the eye. It can damage the nerve that carries information from the eye to the brain. When this happens, you may lose your peripheral vision. Over time, you could lose all of your eyesight.

Which test is commonly used for assessing field of vision?

The automated perimetry test uses a computer program to test an individual’s visual field. You will sit and look into a dome-shaped instrument. Your doctor will instruct you to look at an object in the middle of the dome throughout the test. There will be small flashes of light on the dome.

What does progressive visual field loss mean in glaucoma?

In glaucoma, if visual field loss is progressive, it may mean that control of intraocular pressure (IOP) is inadequate. Be aware, though, that patients may remember to use their eye drops just before they come to the clinic, so that their IOP may appear to be controlled.

What is a glaucomatous visual field defect?

Standard automated perimetry. The key feature of a glaucomatous visual field defect is an abnormality on the pattern standard deviation plot, which also shows on the total deviation plot. A field defect on the total deviation plot, in the absence of a defect on the pattern standard deviation plot, can be due to glaucoma (diffuse field loss),…

What is the difference between glaucoma and neurological field loss?

In order to detect glaucomatous field loss, it is important to test for differences in the superior and inferior hemi-fields (above or below the horizontal raphé) and hunt for defects such as a nasal step, which is typical of glaucoma. In order to detect neurological field loss, test for differences either side of the vertical meridian.

Why repeat visual field testing in glaucoma?

In glaucoma – as well as other conditions – it is vital to repeat visual field testing to track any changes over time. Ideally, the same method of testing should be used for baseline and subsequent follow-up. In glaucoma, if visual field loss is progressive, it may mean that control of intraocular pressure (IOP) is inadequate.