Static vs Kinetic Perimetry – what’s the difference?

08.07.26

Visual field (or perimetry) testing is the gold-standard method for detecting, diagnosing, and monitoring glaucoma. This Glaucoma Awareness Week, we're exploring the differences between static and kinetic perimetry.

What is visual field testing?

Visual field testing is crucial for the diagnosis and monitoring of ocular and neurological conditions. It measures functional visual changes and provides insight into a patient’s visual ability. There are two main methods of visual field testing: static perimetry and kinetic perimetry. Gemma Edwards, UK Product Manager, said:

“The choice between these methods may depend on the condition being tested for, patient compliance, or the region of visual field being tested; in some cases, it is beneficial for both methods to be used together." 

What is static perimetry?

In static perimetry, small light stimuli of varying intensity are projected for a short duration, one by one, across an area of the visual field, in fixed locations. The patient is asked to press the response button when they detect a small flash of light, whilst maintaining their gaze on the central fixation target. Testing aims to define the patient’s sensitivity by measuring the minimum light intensity (the threshold) that can be seen at each position.

Can you give me an example of static testing?

The Octopus G pattern is optimised for glaucoma testing. It tests 59 locations within the central 30° of visual field distributed along the retinal nerve fibre bundles, where visual loss is most likely to occur. It also offers high density of points in the paracentral areas to better map the most important region of visual function.

 

Can static testing be used to test for driving ability?

The standardisation of static testing also makes it appropriate for visual field testing in a legal context, for example to assess a person’s visual ability to drive.

The binocular Esterman test has become the accepted standard visual field test for driving and is identical across all perimeters. It consists of 120 test points which are arranged in the approximate visual field area that can be seen through the front windscreen of a car.

 

What are the benefits of static perimetry?


Standardised: Static testing is the more commonly used method of visual field testing. It is readily available and easier to administer as the testing procedure is automated and standardised.

Accurate: It is ideal for detecting and monitoring visual loss caused by glaucoma, as small changes in sensitivity can be detected with high accuracy. 

What are the challenges with static testing?

Time: To obtain measurements of the patient’s sensitivity threshold would require stimulus intensities of all levels to be shown at each location. This is particularly impractical if there is vision loss across the field. Long testing times can affect a patient’s concentration and comfort, risking the reliability of results.

Low spatial resolution: Lack of information about the sensitivities in the space between testing locations makes it difficult to define the exact boundary of scotomas.

How can we combat these?

Reducing the spacing between points to increase testing density may low spatial resolution, however this would add further time to testing. Additionally, static testing of the periphery requires an extensive number of test locations to cover the entire area, making testing too long for some patients to complete reliably.

Test strategies have been devised to reduce testing times by approximating sensitivity thresholds, while still providing clinically relevant information. For example, the TOP testing strategy assumes that neighbouring points will share similar sensitivity thresholds, so will cut glaucoma testing time down to 2-4 minutes from the 10-12 minutes needed with full threshold testing.

What is kinetic perimetry?

In kinetic perimetry, sensitivity thresholds are determined by moving stimuli from a region of non-seeing to a region of seeing along a desired trajectory called a vector. Vectors can start in the far periphery and point toward central fixation. They can also start within the scotoma and move outwards. The patient is asked to press the response button once the light is seen.

When a sufficiently large number of vectors are tested throughout the visual field with the same stimulus, the response points can be connected to form a boundary of equal sensitivity. This boundary is called an isopter. Kinetic testing aims to identify the isopter for varying stimulus size and intensity and locate possible scotoma within the seeing areas. 

What are the benefits of kinetic perimetry?

High spatial resolution: In contrast to static perimetry, kinetic perimetry has higher spatial resolution as all the locations along the vector are being tested as the stimulus moves. This is especially beneficial for clearly defining boundaries of vision loss and small scotomas like the physiological blind spot. Testing of the periphery is also much faster as a large area can be covered in a relatively short time with moving stimuli.

Adaptability: Kinetic testing may also be easier for certain patients as testing is adaptable, and moving stimuli are easier to detect than non-moving ones making it more suitable for patients who would otherwise struggle with standard static testing. 

What are the challenges with kinetic perimetry?

Constant monitoring: Kinetic testing is highly versatile, but it cannot be fully automated thus requires a highly skilled examiner to constantly monitor patient responses, and modify vector locations as necessary.

Inter-examiner variability: There is no standard method of conducting kinetic perimetry which may lead to inter-examiner variability. The Octopus 900 aims to reduce some variability by motorising the movement of stimuli, so their speed is exact. In addition, by supporting the use of kinetic templates which can be applied consistently across patients and at successive visits.


Conclusion

Both static and kinetic perimetry are valuable methods of visual field assessment, each offering distinct advantages and limitations. Static perimetry provides standardized, sensitive, and reproducible measurements, while kinetic perimetry offers greater flexibility and spatial resolution. The choice of method should be guided by the clinical purpose and the patient’s ability to perform the test reliably. In many cases, combining both approaches can provide the most comprehensive evaluation of visual function.

 

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