How Automated Perimetry Works & How We Save You Time & Money

Excedr - Automated Perimeters

Excedr’s leasing program can source virtually all instrument types and can accommodate any brand preferences your end-user might have. Request an estimate today and see how leasing can discount your automated perimeter’s price.

All equipment brands/models are available

The Advantages of Excedr’s Automated Perimeter Leasing Program:

  • Eliminates the upfront cost of purchasing equipment by spreading its cost over time
  • Minimizes equipment downtime with included complete repair coverage and preventive maintenance
  • Takes advantage of potentially 100% tax deductible* payments, providing you significant cash-savings
  • Expedites the administrative work needed for instrument procurement and logistics
  • Conserves working capital,  enabling you to reinvest in your core business and operations (staffing, inventory, marketing/sales, etc.)
  • Accommodates all manufacturer and model preferences

*Please consult your tax advisor to determine the full tax implications of leasing equipment.

A person’s visual field is the entire area they can see when looking at one fixed position. To test a patient’s eyesight and pinpoint vision issues, a visual field test is conducted using various techniques

In ophthalmology, perimetry is one such technique, and is used to detect, diagnose, and monitor a range of retinal, optic nerve, brain, and other various eye conditions and disorders, as well as scotomas, or blind spots. Furthermore, it can be used to identify peripheral vision loss, as this can be an early sign of glaucoma.

For this reason, perimetry and visual field testing make up for the limitations that visual acuity testing presents.

Detection, diagnosis, and monitoring are all accomplished using an automated perimeter, which employs perimetry to obtain results.

A perimeter works by projecting stimuli of different sizes and densities at different locations throughout a patient’s visual field, and may even flicker the images. The patient’s response to different stimuli size and density, as well as motion and flicker, is then recorded and measured, and the test results can then help an optometrist or ophthalmologist make an accurate diagnosis regarding their ocular health. 

Although tests can be conducted manually, automated perimetry is fast becoming the preferred method for visual testing. Automation can correct human errors and bias, standardizing both stimuli presentation and data recording, and providing more accurate and reproducible results.

Furthermore, automated perimetry is utilized in clinical applications because of its ability to provide an early diagnosis of specific eye conditions. Data collected through perimetry has helped determine associations between patterns of loss of visual sensitivity in specific areas of the eye and eye diseases such as glaucoma. 

Proper early glaucoma diagnosis using visual field tests can lead to important treatment of the disease before serious effects have taken place. Or, at the very least, they can monitor its progression and provide insight into helpful treatment programs.

Having advanced, adaptive, and well-made perimetry equipment in your practice or laboratory is essential to providing patients with an optimal experience.

Types of Perimetry, Perimeters, & Their Benefits

With developments in automation, computerized testing has become more common. Automated perimeters employ varying types or modes of perimetry testing strategies and algorithms to conduct tests and obtain results. We’ll review some of the types of perimetry used in ophthalmology, along with some of the common perimeter types.

Goldmann Perimetry

There are several types of perimeter tests, all of which have similar purposes and functions. Goldmann perimetry, also known as Goldmann visual field tests, are a well known type of perimetry.

In a Goldmann visual field examination, the patient is told to look in the center of a white, hollow, bowel. The examiner then starts the test and lights will begin to flash at varying frequencies and intensities. In a Goldmann visual field tests can be described as static perimetry or kinetic perimetry depending on whether the lights remain in one location or if they move. This technique is often used to monitor changes in glaucoma patients’ vision.

 

Microperimetry

Most conventional perimeter tests require the patient to stare at a fixed location and identify lights of varying intensities and locations in a set area. However, these types of techniques are not considered accurate in determining defects that affect the central part of the eye.

Microperimetry is a visual field test that can be used to detect abnormalities in the central part of the eye. It is used to determine a patient’s macular function using a fundus image and an eye tracker. Microperimetry is also called fundus-related perimetry.

 

Automated Perimetry

The most commonly used perimetry technique is automated perimetry. This type of visual field test uses a perimetry machine to move the stimuli. The use of a white background with lights of incremental brightness is also why it is called white-on-white perimetry. This technique is most commonly used for early detection of blind spots in one’s vision.

 

Manual vs. Automated

There are a number of advantages to automated perimetry when compared to manual perimetry techniques.

Automation allows for a more standardized and reproducible test, with less input required on behalf of the ophthalmologist or technician. This increases overall reliability of testing by providing more accurate control of fixation monitoring, which is how the machine keeps track of the eye’s activity, specifically where and what the eye is looking at.

This greatly reduces the time it takes to complete a visual field test. Automated perimeters may even help the dependability of the patient, as correct patient participation can affect the outcome of testing.

Furthermore, automated devices quickly store data in a computerized system, removing the need for a highly-trained technician to conduct the visual field test.

 

Humphrey Visual Field Analyzers

A Humphrey field analyzer (HFA) is a machine that administers a visual field exam. It is used to detect abnormalities or changes in a patient’s visual field such as monocular visual field impairments. There are several configurations and setups depending on what is being looked for.

  • 10-2: Denotes that 10 degrees temporally and nasally will be measured and 68 points will be tested. This setup is used for glaucoma, macula, and retinal conditions.
  • 24-2: This technique measures 24 degrees temporally, 30 degrees nasally, and has 54 points tested. This setup is used for general screening as well as neuro-ophthalmic conditions.
  • 30-2: Used for measuring temporally and nasally, 30 degrees and testing 76 points. This technique is used for early detection of glaucoma and certain neurological conditions

Additionally, these techniques can either be done in SITA-Standard, SITA-Fast, SITA-Short Wave Automated Perimetry (SWAP), or Esterman. Specifically, SITA-SWAP is used for early detection of glaucomatous loss.

 

SAP

Standard automated perimetry (SAP), which is also referred to as white-on-white perimetry, is considered a gold standard of visual field testing in ophthalmology.

It is used for functional evaluation of patients experiencing glaucomatous damage, specifically in the retinal ganglion cells, a type of neuron located below the surface of the retina. This technique projects moving white stimuli onto a white background that the patient then identifies as it becomes visible to them, determining the threshold of their vision.

Based on this threshold, insight can be provided as to whether or not there is extensive damage to their field of vision. Perimeters that utilize SAP are commonly found in clinics.

 

SWAP

Short-wavelength automated perimetry (SWAP) is also referred to as blue-yellow perimetry for its use of a narrow-band blue stimulus, or light, and an illuminated yellow background.

This technique is often considered to be more sensitive than SAP, as it has detected visual field loss earlier on than standard white-on-white perimeters have. The association between a person with glaucoma and short-wavelength color has been established.

By using this “two-color increment threshold” procedure to focus on specific types of cells in the eye, a much earlier diagnosis can be provided.

 

FDT

Not as commonly used, but nonetheless important, frequency doubling technology perimetry (FDT) is another type of clinical test procedure used in ophthalmology. An FDT perimeter projects different flickering images to which the patient responds.

FDT is based on a phenomenon which makes an image appear double its real spatial frequency. This happens as the test progresses, where flickering black and white bars of a low spatial frequency alternate more quickly at a high rate of temporal frequency, making the image appear as if it’s moving. This is important because contrast sensitivity to frequency doubled stimuli in glaucoma patients decreases.

An FDT perimeter is portable, being smaller in design, and generally produces less blur during the test, making the overall procedure quicker when compared to SAP.

 

SITA

A more recently developed type of algorithm called the Swedish interactive thresholding algorithm (SITA) is a method used to test visual field loss in patients, typically ones that have glaucoma.

This method can be combined with a SAP or SWAP perimeter in order to speed up the time it takes to complete the test while still generating quality, reproducible results. It is often referred to as SITA mode, and most modern perimeters come equipped with it, increasing overall efficiency in the clinic.

Some versions available include SITA Fast (SF), SITA Faster (SFr), and SITA Standard (SS). The difference between these is the speed at which they test for visual field deficiencies, SITA Standard being longest and SITA Faster being shortest.

 

Kinetic vs. Static

Perimeters often rely on either kinetic perimetry and static perimetry to conduct testing:

Kinetic
In kinetic automated perimetry, moving stimuli is used, where the stimuli is brought into a patient’s field of vision, or suprathreshold, from an area out of sight, or subthreshold. The point at which the patient detects this occurrence is then recorded.

An example of kinetic perimetry in use is in manual kinetic Goldmann perimetry, where a stimulus is moved from beyond the edge of a patient’s visual field into their visible field.

Kinetic perimetry is also used in threshold testing—specifically full threshold strategy—where stimuli of different intensity is brought into someone’s field of vision more slowly, and often involves reversals in presentation. Full threshold strategy typically leads to longer testing times.

Static
Static perimetry, or threshold static perimetry, is more commonly associated with automated equipment, and uses different stationary stimuli introduced one at a time throughout the visual field to establish any deficits in a patient’s field of vision.

Standard automated perimetry is an example of threshold static perimetry. Many modern perimeters use static perimetry.

 

The Amsler Grid & Ophthalmology

As a professor of ophthalmology at the University of Zürich, professor Marc Amsler would develop the Amsler grid to help ophthalmologists diagnose visual disturbances. The Amsler grid is a square grid that can be used to test a patient’s central visual field.

During the test, the patient is instructed to look directly at the center of the Amsler grid with each eye separately. If the person suffers from a macular disease, the square grid should appear difformed or wavey in certain places.

Originally the Amsler grid was only blakc and white but color versions have been developed to test for more sensitive conditions. Professor Amsler’s work improved on the previous work from Edmond Landolt. Professor Amsler also helped further our understanding of the uveitis, keratoconus, and in 1951 would perform the first corneal transplant while at the Zürich Eye clinic.

Today the Amsler grid is still used to detect ocular issues and can actually be downloaded from one’s computer to test their eyesight from the comfort of their homes.

 

Visual Field Analyzer & Automated Perimetry Leases to Fit Every Need

Visual field defects can have a huge impact on a patient’s life, and can be an indicator of a potential eye disease or condition. 

Because automated perimetry equipment can accurately and reliably identify many of the abnormalities that are associated with eye disease, it is a key part of ophthalmic pathology and any busy clinic. 

Having an automated perimeter on hand provides a wide range of benefits that include improved efficiency and accurate, reproducible results. However, investing in the acquisition of one of these devices can be difficult due to high costs. 

That said, it is an essential part of ophthalmology and and shouldn’t be skipped simply because acquiring one outright proves financially difficult for your company. 

It’s exactly why Excedr offers a comprehensive leasing program for ophthalmic equipment and instrumentation. With our program, you can bypass that burdensome hurdle of buying something outright and get the equipment you need to better serve your patients. 

Reach out to us today to learn more about leasing your next automated perimeter

Operating Lease

This off-balance sheet financing structure provides three options at the end of the term. The lessee has the option to return the equipment to the lessor, renew at a discounted rate, or purchase the instrument for the fair market value. Monthly payments are also 100% tax deductible which yields additional monetary savings.

Sale-Leaseback

If you recently bought equipment, Excedr can offer you cash for your device and convert your purchase into a long-term rental. This is called a sale-leaseback. If you’ve paid for equipment within the last ninety days, we can help you recoup your investment and allow you to make low monthly payments. This also frees up money in your budget rather than tying it down to a fixed asset.


Automated Perimeter Manufacturers & Models on the Market
Learn More

Zeiss:
ZEISS Humphrey Perimeters, Humphrey Field Analyzer 3, Humphrey Matrix 800, Humphrey FDT, HFA II-i Series

Medmont International PTY. Ltd:
M700

Haag-Streit Diagnostics:
Octopus 900

Nidek Inc.:
MP-1S, MP-3 Microperimeter

Heidelberg Engineering, Inc.:
Heidelberg Edge Perimeter (HEP)

Oculus:
OCULUS Easyfield, OCULUS Easyfield C, OCULUS Centerfield 2, OCULUS Smartfield, OCULUS Twinfield 2

Optopol USA:
OPTOPOL PTS Automated Perimeter Series, PTS 2000, PTS 925Wi

Kowa Ophthalmic:
KOWA AP-7000

CenterVue:
COMPASS, MAIA

Essilor Instruments USA:
M700 Automated Perimeter

 

Operating Capital Benefits

Operating Capital Benefits

Excedr's operating lease structure allows you to keep your business credit line open for expansions, staffing, and other operational expenses. Additionally, it strengthens the cash flow of your business and keeps cash reserves free for business development opportunities.

Effects on Credit

Effects on Credit

Leasing / renting provides you with non-dilutive financing and does not hinder your future borrowing ability. You're able to acquire the equipment you need without the baggage associated with traditional financing.

Used Equipment

Used Equipment

Unlike traditional financing and leasing companies, the Excedr program can accommodate refurbished/reconditioned equipment in addition to demo units. If you are looking for additional cost-savings, we recommend considering this option.

Speed of Approval

Speed of Approval

Excedr's program allows you to respond quickly as your need for equipment and technology arises. You can be approved with minimal documentation and have the equipment you need in operation and generating revenue for your business quickly.