-- DavidKeating - 20 Oct 2008
2. Identification
3. Protocol use(s)
Assessment of macular function
4. Patient population
Patients with retinal diseases which affect macular function
Patients with visual acuity loss with unknown causes
5. Technical issues
(Photograph) TV monitor for the stimulus of focal ERG. The size of stimulus spot: 15 degrees in diameter. Luminance of stimulus spot: 50 cd/m2. Luminance of surrounding area: 5 cd/m2.
6. Response evaluation (with example)
This is the waveform example recorded with 15 degrees (diameter) stimulus spot on the TV monitor (liquid crystal).
(Stimulus: 50 cd/m2, Background: 5 cd/m2, Bandpass: Ch.1 (3-300 Hz), Ch 2 (50-300 Hz). Number of averaging: 300 times.
Amplitude and peak time (implicit time) of the responses (the a-wave, b-wave and OPs) are evaluated (See ref.7).
ISCEV member may think that the luminances of stimulus (50 cd/m2) and background (5 cd/m2) in this system are relatively low.
We have recorded focal ERGs with various stimulus and background conditions, and found that this condition is ideal, because this stimulus condition can produce good waveforms of not only the a- and b-wave, but also oscillatory potentials and d-wave (see above).
7. Reporting and storage
Amplitude and implicit time of the response. All reports should also contain the stimulus parameters (luminance of stimulus and background, stimulus duration, stimulus frequency. It would be also the better if the report contains the representative waveforms and normal ranges.
8. Calibration
No specific definition, see ISCEV Standard (2008 update) and Protocols general aspects
9. Protocol Specifications
10. Relevant References
Module 51 - Focal ERG
To be completed by (Kondo and Seiple)
1. Scope| For assessment of macular function |
| 2.1. Number | 51 |
| 2.2. Version number | 2.0 |
| 2.3. Date of approval |
|
| 4.1. Equipment and facilities | No specific definition for recordings. See ISCEV Standard (2008 update) and Protocols general aspect. For stimulus, various types of stimulus system are used for recording focal ERG. These include TV monitor (CRT, liquid crystal), LED arrays, modified infrared fundus camera, modified funduscope, etc. Focal ERGs usually take specialized equipments to monitor the stimulus spot on the fundus during the recordings. However, these equipments are not universally available. Therefore, we would like to propose a simple focal ERG system with TV monitor or LED arrays (see ref. 6 or 8) for "ISCEV Standard Focal ERG". |
| 4.2. Staff expertise and responsibilities | Recording focal ERGs often need some experiences. |
| 4.3. Procedure | See the standard of pattern ERG (2007 update). |
| 4.4. Patient Information | No specific definition, see ISCEV Standard (2008 update) and Protocols general aspects |
(Photograph) TV monitor for the stimulus of focal ERG. The size of stimulus spot: 15 degrees in diameter. Luminance of stimulus spot: 50 cd/m2. Luminance of surrounding area: 5 cd/m2.
6. Response evaluation (with example)
This is the waveform example recorded with 15 degrees (diameter) stimulus spot on the TV monitor (liquid crystal).
(Stimulus: 50 cd/m2, Background: 5 cd/m2, Bandpass: Ch.1 (3-300 Hz), Ch 2 (50-300 Hz). Number of averaging: 300 times.
Amplitude and peak time (implicit time) of the responses (the a-wave, b-wave and OPs) are evaluated (See ref.7).
ISCEV member may think that the luminances of stimulus (50 cd/m2) and background (5 cd/m2) in this system are relatively low.
We have recorded focal ERGs with various stimulus and background conditions, and found that this condition is ideal, because this stimulus condition can produce good waveforms of not only the a- and b-wave, but also oscillatory potentials and d-wave (see above).
7. Reporting and storage
Amplitude and implicit time of the response. All reports should also contain the stimulus parameters (luminance of stimulus and background, stimulus duration, stimulus frequency. It would be also the better if the report contains the representative waveforms and normal ranges.
8. Calibration
No specific definition, see ISCEV Standard (2008 update) and Protocols general aspects
9. Protocol Specifications
| Description | 5Hz square-wave flicker (100 ms ON and 100 ms OFF) |
| Averages per step |
|
| Adaptation time | At least 10 min for room light |
| Acquisition |
|
| Sample frequency | At least 1000 (Hz) |
| Sweep pre-trigger time | 10 (ms) |
| Sweep post-trigger time | 150-200 (ms) |
| Sweeps per result (number of averaging) | At least 100 (usually 300-500) |
| Interstimulus interval | 200 ms |
| Drift removal | On |
| Manual rejection of sweeps |
|
| DC off-set removal |
|
| Stimulus |
|
| Pulse frequency | 5 Hz square-wave (100 ms ON and 100 ms OFF) |
| Pulse duration (d) | 100 (ms) |
| Stimulus luminance | 30-50 /m² |
| Stimulus color | white |
| Background luminance | 3-5 cd/m2 |
| Background color | white |
| Channels (1 and 2) |
|
| Filter low frequency cutoff | Channel 1: 3 Hz Channel 2: 50 Hz |
| Filter high frequency cutoff | Channel 1: 300 Hz Channel 2: 300 Hz |
| Y-axis scaling |
|
1) Brindley GS, Westheimer G. J Physiol. 1965;179:518-537.
2) Jacobson JH, et al. Invest Ophthalmol. 1969;8:545-556.
3) Biersdorf WR, Diller DA. Am J Ophthalmol. 1969;68:296-303.
4) Hirose T, et al. Arch Ophthalmol. 1977;95:1205-1208.
5) Sandberg MA, Ariel M. Arch Ophthalmol. 1977;95:1881-1882.
6) Seiple WH, et al. Invest Ophthalmol Vis Sci. 1986;27:1123-1130.
7) Miyake Y, et al. Invest Ophthalmol Vis Sci. 1989;30:1743-1749.
8) Falsini B, et al. Curr Eye Res. 1996;15:638-646.
9) Kondo et al. Invest Ophthalmol Vis Sci. 2008;49:3544-3550.
| I | Attachment | Action | Size | Date | Who | Comment |
|---|---|---|---|---|---|---|
 jpg |
Focal_stimulus.jpg | manage | 50.3 K | 23 Sep 2009 - 02:36 | MineoKondo | TV monitor for focal ERG |
| jpg |
Focal_stimulus2.jpg | manage | 48.1 K | 23 Sep 2009 - 02:42 | MineoKondo | |
| jpg |
Focal_stimulus3.jpg | manage | 28.4 K | 23 Sep 2009 - 02:44 | MineoKondo | |
| jpg |
Focal_stimulus4.jpg | manage | 33.4 K | 23 Sep 2009 - 02:46 | MineoKondo | |
| jpg |
Waveform.jpg | manage | 56.1 K | 23 Sep 2009 - 04:17 | MineoKondo | |
 tif |
Waveform.tif | manage | 389.7 K | 23 Sep 2009 - 04:16 | MineoKondo | |
| jpg |
Waveform3.jpg | manage | 46.3 K | 23 Sep 2009 - 04:27 | MineoKondo |
Topic revision: r8 - 23 Sep 2009 - 12:56:01 - MineoKondo
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