What is the esterman visual field test?
Esterman visual field perimetry is a binocular testing method which is also available on the HFA. The test consists of 120 white test points shown with equal, non-adjustable suprathreshold light intensity of 10 dB and examines more than 130° of the field.
What is normal visual field index?
The VFI can range from 100% (normal visual field) to 0% (perimetrically blind field). The VFI has been shown to be less susceptible than the MD to the effects of cataract or diffuse media opacities. VFI is intended for use in calculating rates of progression and staging glaucomatous functional damage.
How do you do a esterman field test?
The Esterman Visual Field Test is carried out on both eyes together (binocularly) and wearing any glasses that you normally wear when driving. It is carried out on a visual field analyser, a computerised machine where you have to responding to small, flashing lights by pressing a button whilst looking straight ahead.
What do the numbers mean on a visual field test?
The visual threshold is the intensity of stimulus seen 50% of the time at each location. The threshold values of each tested point are listed in decibels in the sensitivity plot. Higher numbers mean the patient was able to see a more attenuated light, and thus has more sensitive vision at that location.
How many degrees is esterman visual field?
The Esterman tests a total field extent that approximates 145 degrees rather than “extends to 160 degrees temporally on both sides.” The Esterman tests (both binocular and monocular) use the same stimulus intensity as the other Humphrey screening tests, which would obviously differ from a threshold test.
What is the minimum visual field for driving?
Drivers must have a horizontal field of vision of at least 120 degrees. In addition, the extension should be at least 50 degrees left and right and 20 degrees up and down. No defects should be present within the radius of the central 20 degrees. This requirement applies to drivers who are binocular or monocular.
How do you read an eye field test?
Use this order to interpret your Humphrey visual field every time:
- Confirm it’s the right patient with name and date of birth.
- Confirm it’s the right/left eye.
- Look at the reliability indices.
- Look at the pattern.
- Look at the GHT, mean deviation, VFI, and pattern standard deviation.
- Compare to the previous visual fields.
What VFI is legally blind?
What is legally blind? The formal description of legal blindness is: “Central visual acuity 20/200 or less in the better eye with best correction, or widest diameter of visual field subtending an angle of no greater than 20 degrees.”
What is a Group 1 DVLA eye test?
The minimum field of vision for Group 1 driving is defined in the legislation: A field of at least 120° on the horizontal measured using a target equivalent to the white Goldmann III4e settings. The extension should be at least 50° left and right.
Can I read a number plate from 20m away?
In good daylight, you must be able to read a vehicle number plate from a distance of 20 metres (or from a distance of 20.5 metres for old style number plates). If you want to do your own number plate test, when walking down a street or in a car park, 20 metres is about 5 car lengths.