The ‘two global flash’ mfERG in high and normal tension primary open-angle glaucoma
- 92 Downloads
To analyse the sensitivity of the ‘2 global flash’ multifocal electroretinogram (mfERG) to detect glaucomatous dysfunction in normal tension (NTG) and high tension primary open angle glaucoma (POAG) patients.
MfERGs were recorded from 20 NTG and 20 POAG patients and compared to those of 20 controls. The mfERG array consisted of 103 hexagons. Each m-sequence step started with a focal flash that could be either dark or light (m-sequence: 2^13, L max: 200 cd/m2, L min: 1 cd/m2), followed by two global flashes (L max: 200 cd/m2) at an interval of ∼26 ms. Focal scalar products (SP) were calculated using focal templates derived from the control recordings (VERIS 4.8). We analyzed 5 response averages (central 7.5 degrees and 4 adjoining quadrants) of the response to the focal flash, the direct component at 10–40 ms (DC) and the following two components induced by the effects of the preceding focal flash on the response to the global flashes at 40–70 ms (IC-1) and at 70–100 ms (IC-2).
Both NTG and POAG patients differed from controls in the IC-1 response to the superior quadrants, and POAG patients also differed from controls in the centre. The most sensitive parameter was the IC-1 of the superior temporal quadrant with an area under the ROC curve of 0.82 for POAG and 0.79 for NTG. The DC and the IC-2 did not differ significantly between the groups. When all five response averages of the IC-1 were taken into consideration 90% of the NTG patients and 85% of the POAG patients were correctly classified as abnormal while 80% of the control subjects were correctly classified as normal.
This stimulus sequence holds promise for the diagnosis of early functional changes in POAG. A new finding is that both NTG, as well as POAG can be differentiated from control subjects.
KeywordsmfERG Global flash Glaucoma POAG Normal tension glaucoma
We thank Andy Schötzau for statistical advice and Pfizer for grant support (APW,MT).
- 11.Sutter EE, Bearse MA Jr (1995) Extraction of a ganglion cell component from the corneal response. In: America OSo, ed. Santa Fe: OSA, 1995; v. 1Google Scholar
- 12.Bearse M, Sutter EE, Smith DN, Stamper R (1995) Ganglion cell components of the multi-focal ERG are abnormal in optic nerve atrophy and glaucoma. Investigative Ophthalmology and Visual Science 36:S445Google Scholar
- 13.Bearse MA, Sutter EE, Palmowski AM (1997) New developments toward a clinical test of retinal ganglion cell function. In: America OSo (ed) Vision science and its applications, vol. 1. Washington DC, Optical Society of AmericaGoogle Scholar
- 14.Bearse MAJ, Sutter EE, Palmowski AM (1997) Luminance-dependent enhancement of ganglion cell contributions to the human multifocal ERG. Invest Ophthalmol Vis Sci 38(4):S959Google Scholar
- 17.Bearse MA Jr, Sim D, Sutter EE et al (1996) Application of the multi-focal ERG to glaucoma. Investigative Ophthalmol & Visual Sci 37(3):S511Google Scholar
- 18.Bearse MA, Sutter EE (1998) Contrast dependence of multifocal ERG components. In: America OSo (ed) Vision science and its applications, vol 1. Washington DC, Optical Society of AmericaGoogle Scholar
- 20.Hood DC, Birch DG (1995) Computational models of rod-driven retinal activity, 14:59–66Google Scholar
- 21.Bearse MA, Sutter EE, Shimada Y, Yong Y (1999) Topographies of the optic nerve head component (ONHC) and oscillatory potentials (OPS) in the parafovea. Invest Opthaltmol Vis Sci 40:S17Google Scholar
- 23.Sutter EE, Bearse MA, Shimada Y, Li Y (1999) A multifocal ERG protocol for testing retinal ganglion cell function. Invest Ophthalmol Vis Sci:S15Google Scholar