scholarly journals Integrated electrophysiological evaluation in early normal-tension glaucoma

2016 ◽  
Vol 1 (2) ◽  
pp. 79-88
Author(s):  
Dario Messenio ◽  
Giuseppe Marano ◽  
Elia Biganzoli
Keyword(s):  
Optic Nerve ◽  
Visual Field ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Optic Nerve Head ◽  
Pattern Electroretinogram ◽  
Normal Subjects ◽  
Visual Field Defects ◽  
Control Group ◽  
Visual Evoked

Purpose: To evaluate the variations of intraocular pressure (IOP), morphometric optic nerve head characteristic, perimetric indices and electrophysiological parameters (pattern electroretinogram and visual evoked potentials) before and after topical IOP lowering in patients with early normal-tension glaucoma.Methods: we evaluated 38 eyes of 20 patients with IOP < 21 mmHg, initial glaucomatous optic neuropathy (valued with HRT: retinal nerve fiber layer thickness (RNFL) and linear cup/disk ratio (linear C/D ratio)), minimal visual field defects (Octopus 101: G2 program), best correct visual acuity more than 15/20 and pathological electrophysiological parameters (valued with pattern electroretinogram (PERG) and visual evoked potentials (VEPs)), free of systemic or other ocular diseases. All parameters were evaluated at the beginning of the study (T0) and after 12 months of therapy (T12). A randomized normal control group (27 eyes of 14 subjects) with apparent larger disc cupping underwent all exams at initial of study (T0) and after 12 months (T12).Results: Among electrophysiological parameters, at the beginning of the study NTG P100 VEPs latency is slightly increased and P100 amplitude is reduced compared to normal subjects. There are not significant variations after 12 months. P50 PERG latency in NTG is quite similar respect normal and do not modify after therapy. P50N95 complex PERG amplitude in NTG is reduced compared to normal subjects and slightly increases after 12 months (1.8 vs 1.5 ; 2.4 vs 1.9 micronvolts, with different checkboard spatial frequency). Cortical retinal time (CRT) is slightly delayed in NTG and does not modify. Among visual field indices, MD and CLV is slightly higher in NTG and do not significantly modify after therapy. Among morphometric optic nerve head characteristics, linear C/D and RNFL thickness are quite similar in NTG and do not modify. IOP is quite similar between NTG and control group and modifies in NTG after therapy.Conclusion: In a viewpoint of an integrated diagnostic, electrophysiological tests (VEPs and PERG) could provide a more sensitive measure of retinal ganglion cell integrity and help to distinguish between early normal-pressure glaucoma patients with no or minimal visual field alterations and normal subjects with apparent larger disc cupping.

scholarly journals Electrophysiological evaluation in normal-tension glaucoma suspects: a pilot study

2017 ◽  
Vol 1 (3) ◽  
pp. 9-30
Author(s):  
Dario Messenio ◽  
Giuseppe Marano ◽  
Elia Biganzoli
Keyword(s):  
Intraocular Pressure ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Pattern Electroretinogram ◽  
Normal Subjects ◽  
Control Group ◽  
Glaucomatous Optic Neuropathy ◽  
Cell Integrity ◽  
Fiber Layer ◽  
Visual Evoked

Purpose: To evaluate the variations of intraocular pressure (IOP), morphometric papillary characteristics, perimetric indices and electrophysiological parameters (Pattern electroretinogram and visual evoked potentials) before and after topic hypotonization therapy in patients with suspect normal tension glaucoma.Methods: we evaluated 38 eyes of 20 patients with intraocular pressure < 21 mmHg (measured with Goldman applanation tonometry), initial glaucomatous optic neuropathy (valued with HRT: retinal fiber layer (RNFL) and/or linear cup/disk (linear C/D), minimal visual defects (Octopus 101: G2 program), visual acuity more than 15/20 with best correction and pathological electrophysiological parameters (valued with pattern electroretinogram and visual evoked potentials), free of systemic or other ocular diseases. All parameters were evaluated at the beginning of the study (T0) and after 12 months from the beginning of the therapy (T12). A randomized normal control group (27 eyes of 14 subjects) with apparent larger disc cupping underwent all exams at initial of study and after 12 months. Results:At T0, P100 Latency VEPs in LTG was slightly increased either at 15’ (12,9 msec) and 30’ (8,9 msec). At T0, P100 Amplitude VEPs in LTG group were reduced compared to normal subjects, with average differences of: -6.4 µV (95% C.I.: (-9.8, -3.0) µV) for 15'; and: -5.4 µV (95% C.I.: ( -8.9, -2.0) µV) for 30’. P50N95 complex amplitude PERG was reduced at T0 in LTG, with average differences: -0.9 (95% C.I.: ( -1.4, -0.4) µV), -0.8 (-1.3, -0.3) µV) for 15’ and 30’, respectively; than it improved after therapy, with average differences between T12 and T0 of 0.3 µV (95% C.I.: (0.1, 0.6) µV) and 0.5 µV (95% C.I.: ( 0.2, 0.8) µV). So IOP decreased at T12 in LTG group, with an average difference between T12 and T0 of -5.2 mmHg (95% C.I.: (-5.9, -4.4). mmHg). Finally, CRT was slight delayed in LTG group at T0. Conclusion: In a viewpoint of an integrated diagnostic, electrophysiological tests (VEPs and PERG) could provide a more sensitive measure of retinal ganglion cell integrity and help to distinguish between suspect normal-pressure glaucoma patients before perimetric alterations are evident and normal subjects with apparent larger disc cupping.

Innovative evaluation of visual field defects in epileptic patients after standard anterior temporal lobectomy, using partial field visual evoked potentials

2010 ◽  
Vol 90 (1-2) ◽  
pp. 68-74 ◽  
Author(s):  
Margarita Minou Báez Martín ◽  
Yamila del Carmen Pérez Téllez ◽  
Lilia María Morales Chacón ◽  
Bárbara Estupiñán Díaz ◽  
Otto Trápaga-Quincoses ◽  
...  
Keyword(s):  
Visual Field ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Temporal Lobectomy ◽  
Visual Field Defects ◽  
Anterior Temporal Lobectomy ◽  
Epileptic Patients ◽  
Field Defects ◽  
Visual Evoked

Monitoring visual evoked potentials during retraction of the canine optic nerve: protective effect of unroofing the optic canal

1995 ◽  
Vol 82 (2) ◽  
pp. 284-287 ◽  
Author(s):  
Akira Akabane ◽  
Kiyoshi Saito ◽  
Yoshio Suzuki ◽  
Masato Shibuya ◽  
Kenichiro Sugita
Keyword(s):  
Optic Nerve ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Time Course ◽  
Light Emitting Diode ◽  
Canine Model ◽  
Optic Canal ◽  
Control Group ◽  
Content Type ◽  
Visual Evoked

✓ To evaluate the effects of unroofing the optic canal during retraction of the optic nerve, the authors monitored changes in visual evoked potentials (VEPs) stimulated by a light-emitting diode in the canine model. At rest, an early VEP wave was reliably observed with an amplitude of 8.2 ± 0.6 µV and a latency of 51.5 ± 0.7 msec; this wave was named N50. The intracranial optic nerve was retracted using a weight of 5, 10 or 50 g. The earliest change in VEP noted during retraction was a reduction in N50 wave amplitude. The length of time required until N50 amplitude decreased to 50% of the control group (T50) was 10.7 ± 1.8 minutes with a weight of 5 g, 4.9 ± 0.7 minutes with 10 g, and 2.9 ± 0.4 minutes with 50 g, with statistically significant differences between the groups. Retraction of the optic nerve with all weights finally resulted in the disappearance of the N50 wave. The amplitude of the N50 wave recovered fully to control size when retraction was released immediately after the wave disappeared. The time course of amplitude recovery did not differ significantly between groups. Unroofing the optic canal prolonged the T50 during retraction significantly to 20.7 ± 2.9 minutes with a weight of 5 g, 18.9 ± 4.2 with 10 g, and 9.0 ± 2.4 with 50 g. These results demonstrate that unroofing the optic canal can protect the optic nerve from damage during operations that require optic nerve retraction.

201. Visual evoked potentials: An objective evaluation of the visual field defects consecutive to temporal lobotomy in epileptic patients

2008 ◽  
Vol 119 (9) ◽  
pp. e148
Author(s):  
M.M. Báez Martín ◽  
Y. Pérez Téllez ◽  
L. Morales Chacón ◽  
I. Cabrera Abreu ◽  
B.O. Estupiñán Díaz ◽  
...  
Keyword(s):  
Visual Field ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Objective Evaluation ◽  
Visual Field Defects ◽  
Epileptic Patients ◽  
Field Defects ◽  
Visual Evoked

scholarly journals Significance of Visual Evoked Potentials in the Assessment of Visual Field Defects in Primary Open-Angle Glaucoma: A Review

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ruchi Kothari ◽  
Pradeep Bokariya ◽  
Smita Singh ◽  
Ramji Singh
Keyword(s):  
Visual Field ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Objective Measure ◽  
Visual Field Defects ◽  
Open Angle ◽  
Field Defects ◽  
Visual Evoked

Visual evoked potentials is an important visual electrophysiological tool which has been used for the evaluation of visual field defects in primary open-angle glaucoma and is an appropriate objective measure of optic nerve function. Significant correlations between the magnitude of the VEP parameters and MD of Humphrey static perimetry suggest that the impaired visual cortical responses observed in glaucoma patients can be revealed by both electrophysiological and psychophysical methods. In addition, the severity of global glaucomatous damage evidenced by reduction in MD could depend on the delay in neural conduction from retina to the visual cortex as revealed by the significant correlation between VEP latencies and MD which also supports the validity of the VEP testing in progression of glaucoma.

Nonlinear Analysis of Visual Evoked Potentials Elicited by Color Stimulation

1997 ◽  
Vol 36 (04/05) ◽  
pp. 315-318 ◽  
Author(s):  
K. Momose ◽  
K. Komiya ◽  
A. Uchiyama
Keyword(s):  
Visual System ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Normal Subjects ◽  
Second Order ◽  
First Order ◽  
The Relationship ◽  
Perceived Color ◽  
Second Order Nonlinearity ◽  
Visual Evoked

Abstract:The relationship between chromatically modulated stimuli and visual evoked potentials (VEPs) was considered. VEPs of normal subjects elicited by chromatically modulated stimuli were measured under several color adaptations, and their binary kernels were estimated. Up to the second-order, binary kernels obtained from VEPs were so characteristic that the VEP-chromatic modulation system showed second-order nonlinearity. First-order binary kernels depended on the color of the stimulus and adaptation, whereas second-order kernels showed almost no difference. This result indicates that the waveforms of first-order binary kernels reflect perceived color (hue). This supports the suggestion that kernels of VEPs include color responses, and could be used as a probe with which to examine the color visual system.

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