New Light on Glaucoma
Table of contents
- Multi-Modality Perimetry
- Flicker-Defined Form Perimetry
- Standard Automated Perimetry
- Standard Tests
- Thresholding Strategies
- Trend Analysis
Visual field testing remains the main diagnostic tool to provide information about a patient’s visual function, quality of vision and quality of life. Functional testing supports clinicians in early disease detection, staging of disease or trend analysis in progressive glaucoma.
2-in-1 perimetry with Heidelberg Engineering Perimeter (HEP) offers the most appropriate test for each stage of disease. It allows you to offer the right stimulus to your patient at the appropriate stage of disease.
Flicker-Defined Form Perimetry
The Flicker-Defined Form (FDF) stimulus or contour “Edge” illusion has been shown to be useful for detecting visual field loss in patients with early glaucoma(3).
A 5-degree circular stimulus is created by a phase reversal of black and white dots that flicker in counter-phase to the background dots.
The flicker creates an illusionary edge contour that the patient perceives as a gray patch or circle against the mean luminance background(4). FDF perimetry has been proven to correlate to structural defects detected by HRT or SPECTRALIS® OCT(5,6).
Standard Automated Perimetry
Standard Automated Perimetry (SAP) or white-on-white perimetry is best suited for patients with moderate to severe progressive disease and thereby offers continuity of care. The HEP monitor-based system offers full dynamic range perimetry and has proven to deliver equivalent results to a projection-type perimeter(7,8).
The HEP offers a unique white-on-white perimetry using a Goldmann size III target for the 40 dB to 16 dB range. From 15 dB to 0 dB, the stimulus size is increased following the Goldmann equation to give perceptual equivalence(9). This unique approach enables full-range SAP and ensures good test-retest characteristics.
Heidelberg Edge Perimeter is a monitor-based perimeter designed to test central and peripheral vision. It offers a full set of standard tests for the central 10°, 24° and 30° visual field as well as an extension to the periphery up to 60°.
The HEP uses three different kinds of Adaptive Staircase Thresholding Algorithm (ASTA) strategies covering a broad range of applications.
The ASTA Standard algorithm for baseline examinations uses a 4-2-2 staircase approach as well as neighboring test target information and a quick termination methodology to reduce test time.
ASTA Follow-Up further reduces the test time during followup examinations. Results of previous tests are used to seed each location of the field. Test time reductions resulting in a three minute test are typically achieved while maintaining the same test sensitivity.
ASTA Fast is a short test protocol advised for patients expected to be “within normal limits” or those who have previously shown unusual levels of fatigue. Starting values are based on age-matched normal values.
HEP´s Functional Change Analysis (FCA) applies existing knowledge of the random variability of visual field analyses and flags progressive visual field loss that exceeds the normal level of repeatability. FCA is compatible with ASTA Standard and ASTA Follow-Up examinations.The FCA is a trend analysis to provide information on significant change in probability maps for total deviation as well as for pattern deviation.
Easy-to-read symbols are used to indicate a worsening visual field and assist with interpretation. FCA is the only trend analysis that can monitor subtle change in early disease with FDF perimetry and manage long-term follow-up in advanced glaucoma patients with SAP.
- 1 Rogers-Ramachandran D. et al.; Vision Research 1998;38:71-77.
- 2 Flanagan JG. et al.; Perimetry Update 1994/1995; 405-409.
- 3 Fingeret M. et al.; ARVO 2010; Program/Poster: 5509/A564.
- 4 Quaid P. et al.; Vision Research 2005;45:1075-1084.
- 5 Butty Z. et al.; ARVO 2011; Program/Poster: 4145/A598.
- 6 Ho Y.-H. et al.; ARVO 2011; Program/Poster: 5076/A56.
- 7 Goren D. et al.; ARVO 2010; Program/Poster: 4335.
- 8 Ferreras A. et al.; ARVO 2011; Program/Poster: 5524/A325.
- 9 Anderson D.R. and Patella V.M.; Automated Static Perimetry. 2nd Edition (1999). Mosby. pp 26-27.