Twinfield 2

The Examination Programs

The pre-defined test programs of the Twinfield^® 2 perimeter have been set up in such a way that you can easily perform the examinations that you require most often. Whether glaucoma, age-related macular degeneration, neurological diseases – appropriate examinations are available for them all. Furthermore, the modular setup of these programs enable you to create custom test processes, as all available test point grids can be conveniently combined with all OCULUS test strategies. You can thus extend the comprehensive standard program series to meet your own particular requirements.

The OCULUS Test Strategies

To gain as much information in the shortest possible time – this principle has always been heeded in the development of all OCULUS test strategies.  The SPARK Strategy incorporates data from more than 90 000 diagnoses in a matter of minutes to give precise and stable measurements, especially in Glaucoma detection, diagnosis and progression analysis.  The OCULUS Fast Threshold achieves a similar performance with clever improvements to the classic 4-2 step method.  And since exact numeric values of the perception threshold do not, in many cases, show any priority, the multiple suprathreshold strategies available in the Twinfield^® 2 perimeters offers a faster and more comfortable alternative.

The OCULUS Test Point Grid

Optimally selected examination areas significantly contribute to meaningful visual field findings. The Twinfield^® 2 perimeter provides comprehensive, pre-defined test point grids, which cover all areas ranging from the macula area to the entire field of vision. Grids with a higher density of test points in the center, which take account of the physiology of the retina, are the trademark of the Twinfield^® 2. Grids with uniform, orthogonally distributed test points along with other grids, such as the Esterman grid, complete the list of available examination areas.

Results Printout

The measuring results of the Twinfield^® 2 perimeter are summarized in the standardized results printout. For threshold-determining examinations, all clinically relevant data are recorded and are shown in various different depictions whereas for suprathreshold tests, only a single informational overview is printed.

SPARK Strategy

The SPARK examination strategy was primarily developed for glaucoma patients and is available for all OCULUS perimeters. It is based on data from more than 90 000 perimetric diagnoses and allows a very fast, yet very precise measurement of the thresholds in the central field of vision. The modular configuration of the method makes it suitable for a variety of applications:

• SPARK Precision (optional software) is the full version. The complete examination of the field of vision of glaucoma patients takes only 3 minutes per eye. The greater stability of the results allows for much better progression analysis.
• SPARK Quick is the strategy used for progression or screening examinations. The test takes just 90 seconds per eye.
• SPARK Training is ideal for patient training. The 40 seconds measurement can also be used as a screening examination.

Glaucoma Staging Program (GSP)

The Glaucoma Staging Program (GSP) is useful in early detection of Glaucoma.

The GSP software grades examination findings into visual field classes (normal, glaucomatous, artifactual and neuro) based solely on their appearance. In addition, risk classes (normal, suspect, pre-perimetric, early stage, moderate and severe) are also assigned to findings of different severities that are classified as normal or glaucomatous. The examination results are presented in easy to understand green, yellow and red bar charts.

The striking novelty of the GSP is its ability to detect subtle changes in the visual field associated with early stage Glaucoma. Findings in the suspect and pre-perimetric risk classes contain reductions in the visual field that cannot be readily seen by the examiner. They usually remain undetected by the standard perimetric indices.

The Glaucoma Likelihood Index (GLI) summarizes the results of the GSP classification into a single parameter, presenting a value of between 0 (normal) and 5 (advanced Glaucoma).

The Glaucoma Staging Program (GSP) is available for the OCULUS Twinfield^® 2, Centerfield^® 2, Smartfield and Easyfield^® perimeters. This upgrade is available for the existing units.

Threshold Noiseless Trend (TNT) Progression Analysis

TNT provides a quantitative, statistical analysis of the visual field examination results conducted over time. For follow-up purposes, the software uses the visual field results and patient’s threshold values supplied by 30-2, 30×24 or 24-2 grids over the entire examination period. TNT uses a specific filter to reduce the fluctuation range of the threshold values and to perform a consistent trend analysis. In conjunction with the fast SPARK strategy, the sensitivity of detecting progression of early stage glaucoma is greatly improved.

• TNT creates a concise progression analysis report containing the most important parameters (MD increase, p-values, etc.).
• TNT can differentiate between diffuse and focal progression based on the focusing index (FI) value.
• TNT applies multiple statistical criteria to establish possible progression.
• TNT displays the prognosis of the expected visual field for a patient age-group selected by the examiner.