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M.G. Todorova, A.M. Palmowski–Wolfe, S. Orgül; Multifocal On–Off ERG in Open–Angle Glaucoma Patients . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3439.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: With long stimulus duration, ON and OFF responses can be elicited with the multifocal electroretinogram (mfERG).We report an application of a light emiting diode screen (LED) to elicit mfERG ON– and OFF– responses in patients with open–angle glaucoma (POAG) in order to investigate the utility of the ON–OFF mf ERG in POAG and compare the results of the mf ERG to visual fields. Methods: ON–OFF mfERGs were recorded from 11 POAG patients: 7 normal–tension glaucoma (NTG) and 4 high–tension glaucoma (HTG) and compared to 11 control subjects. A mf ERG (RetiscanTM ) with a stimulus matrix of 61 elements was performed with a LED stimulus screen. The stimulus length was 200 ms, with an ON phase of 100ms and an OFF phase of 100ms. The filter setting was : 10– 200 Hz. Responses of the mfERG were analyzed as an overall response and in quadrants and were compared with the mean sensitivity values (dB) of the corresponding quadrant of the Humphrey static perimetry. Results: In the overall response the amplitude of the ON response was 11.5 (SD 3.82 ) in the POAG patients which compared to 15.81(SD 9.59 ) in the control group. Mean and standard deviations of the overall OFF response amplitude were 4.66 (SD 1.37) for POAG and 4.47 (SD 7.06) for controls.The values of the latencies are described in the following order: mean deviation of POAG patients (standard deviation) / mean deviation of controls (standard deviation ). N1of the ON response 18.37 (SD 1.92)/ 18.64 (SD 1.22), P1 of the ON response 33.76 (SD 3.14)/ 34.88 (SD 4.32), N1of the OFF response 107.35 (SD 2.32)/ 107.88 ( SD 3.01), P1of the OFF response 122.16 (2.55)/ 124.60 (SD 5.43). Neihter the amplitudes nor the latencies of the ON– nor of the OFF–responses differed significantly from normal. Furthermore, mfERG parameters did not correlate with the glaucomatous visual field defects. Conclusions: The present study findings sugest that neither ON nor OFF bipolar cells contribute significantly to the changes observed in the fast mfERG of glaucoma patients.
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