P100 Latency Of Visual Evoked Potentials Research Articles

Evoked potential response in patients with idiopathic Parkinson’s disease and atypical parkinsonian syndromes: A comparative study

Patients with idiopathic Parkinson’s disease (IPD) and atypical parkinsonian syndromes (APSs) suffer from a range of disorders, especially in balance and locomotion, which necessitate visual, auditory, and somatosensory inputs. In this study, IPD patients, APS patients, and healthy controls (HCs) (n = 50 per group) underwent a series of assessments for visual evoked potentials (VEP), brainstem auditory evoked response (BAER), and short-latency somatosensory evoked potentials (SSEP). Results showed that VEP P100 latency was prolonged in multiple system atrophy-cerebellar type (MSA-C), multiple system atrophy-parkinsonian type (MSA-P), and corticobasal ganglionic degeneration (CBD) patients. The latency of peaks III and V was prolonged in IPD, MSA-C, dementia with Lewy bodies (DLB), and Parkinson’s disease dementia (PDD). BAER I-III and I-V interpeak latency were prolonged in IPD, DLB, and PDD, whereas BAER I-III, III-V, and I-V interpeak latencies were increased and the V/I amplitude ratio was decreased in MSA-C. The central sensory conduction time (N20-N13) was increased in MSA-P and MSA-C in SSEP. IPD patients had prolonged VEP P100 latency (P < 0.001), lower VEP N75-P100 amplitude (P < 0.001), prolonged BAER I, II, II, IV, V peak latencies (P < 0.001), I-III, I-V interpeak latencies (P < 0.001), lower BAER V/I amplitude ratio (P < 0.001), and prolonged SSEP N13, N20, central sensory conduction time (N20-N13) (P < 0.001) than HCs. IPD patients also had prolonged BAER I, II, II, IV, V peak latencies (P < 0.001), prolonged I-III, I-V interpeak latencies (P < 0.001), and shorter SSEP N13, N20, central sensory conduction time (N20-N13) (P < 0.001) than APS patients. Moreover, APS patients had prolonged VEP P100 and N145 latencies (P < 0.001) and decreased N75-N145 amplitude (P < 0.001) compared to HCs. APS patients also had prolonged BAER II, II, IV, V peak latencies (P < 0.001), prolonged I-III, III-V, I-V interpeak latencies (P < 0.001), decreased V/I amplitude ratio, and prolonged SSEP N13, N20, central sensory conduction time (N20-N13) (P < 0.001) than HCs. Postural instability and gait disorder (PIGD) IPD had significantly prolonged BAER III, V peak latencies (P < 0.05), and prolonged III-V interpeak latencies (P < 0.05) compared to tremor-dominant IPD. Overall, the IPD and APS patients had significant VEP, BAER, and SSEP abnormalities of demyelination and axonal variety in the visual, auditory, and somatosensory pathways. The changes were also correlated with the disease duration and severity. Although the diseases are predominantly motor disorders with significant non-motor components, these electrophysiological abnormalities might open a new avenue to assess the non-motor symptoms.

OCT and VEP correlate to disability in secondary progressive multiple sclerosis

BackgroundThe afferent visual pathway provides a unique opportunity to monitor clinical and subclinical optic neuritis and features of neuroaxonal degeneration in secondary progressive MS. ObjectiveTo investigate the usefulness of visual evoked potentials (VEP) and optical coherence tomography (OCT) in evaluating SPMS, and the association between these modalities and clinical course and lesion load on the magnetic resonance imaging (MRI) in patients with SPMS with or without a history of optic neuritis (ON). MethodsSPMS patients (n = 27) underwent clinical assessment with Expanded Disability Status Scale (EDSS) grading, visual acuity, OCT, and VEP examination. MRI of the brain and spinal cord were evaluated. Ordinal scores of VEP and MRI findings were used in the statistical analyses. ResultsThe ganglion cell and inner plexiform layer (GCIPL) and retinal nerve fiber layer (RNFL) thickness correlated with VEP latency. VEP P100 score correlated with EDSS. Linear regression showed an association between GCIPL thickness and EDSS as well as VEP P100 latency and EDSS. The MRI analyses were negative. ConclusionVEP latency and GCIPL thickness correlated with disability measured as EDSS in patients with SPMS and are useful in monitoring SPMS patients.

Chromatic visual evoked potentials indicate early dysfunction of color processing in young patients with demyelinating disease.

Chromatic visual evoked potentials (cVEP) primarily reflect the parvocellular visual pathway function, which has been shown to be predominantly affected in demyelinating disease (DD). The purpose of this study was to evaluate cVEP responses and to compare them with other structural and functional findings in young patients with DD. Thirty patients (8-28years of age) with DD with or without a history of optic neuritis (ON) were investigated. Twenty-five eyes had at least one episode of ON (ON-group) and 35 eyes had no clinically evident episode of ON (nON-group). OCT imaging was performed using a high-resolution spectral-domain OCT (SD-OCT), measuring retinal nerve fiber layer (RNFL) thickness. Pattern reversal electroretinography (PERG) and visual evoked potentials (VEP) were recorded according to the ISCEV standard, and chromatic visual evoked potentials (cVEP) were recorded to isoluminant red-green (R-G) and blue-yellow (B-Y) 7° circle stimuli, composed of horizontal sinusoidal gratings with spatial frequency 2 cycles/°, 90% chromatic contrast and onset-offset (300:700ms) mode of stimulation. Structural and functional measures were analyzed and compared between the groups. Both general (G) and temporal (T) RNFL thicknesses were reduced below normal limits in most of the eyes. However, in the ON-group (G: 77.5 ± 20.6, T: 51.4 ± 23.4µm), the thinning was more significant (p < 0.001) than in the nON-group (G: 95.4 ± 12.1, T: 70.1 ± 11.5µm). PERG N95 was within normal limits in the nON-group, while it was significantly more affected in the ON-group (7.4 ± 1.0 vs. 5.1 ± 2.0μV; p < 0.0001). Similarly, also VEP P100 latency and amplitude showed a greater percentage of abnormality in the ON-group, the latency being longer (117.2 ± 16.9 vs. 99.4 ± 4.6ms; p < 0.0001) and the amplitude lower (9.1 ± 5.1 vs. 16.4 ± 7.5μV; p < 0.0001). The cVEP N-wave amplitude to R-G and B-Y stimuli was reduced below normal limits in both ON- and nON-groups; however, cVEP to B-Y stimulation were slightly more affected in the ON-group (4.0 ± 3.8 vs. 5.9 ± 3.3µm; p = 0.02). A positive correlation between cVEP amplitude and RNFL thickness and between cVEP amplitude and PERG N95 amplitude, as well as a strong negative correlation between cVEP amplitude and P100 latency was observed. These findings demonstrate that cVEP indicate early abnormality of parvocellular pathway function in eyes with or without a history of optic neuritis and can be used together with other structural and functional parameters to evaluate visual pathway integrity of young patients with DD.

Visual Evoked Potential in Idiopathic Intracranial Hypertension

Purpose: To study the rule of Visual Evoked Potential (VEP) in evaluation of patient with Idiopathic Intracranial Hypertension (IIH). Methods: The study was carried out on fifty-nine patients presented with IIH from February 2017 to the end November of 2018. All patients were subjected to complete medical, Ophthalmological and neurological history and examination, Lumbar Puncture (LP), VEP, perimetry and MRI brain and MRV were done. Result: We found that 35.59% of patients had prolonged P100 latency of VEP and 22.03% of patients had abnormal visual field. Also there were significant correlation between P100 latency of VEP and duration of disease, opining CSF pressure, and result of perimetry. Conclusion: We concluded that VEP is simple sensitive noninvasive method for evaluation of visual function in patients with ICH.

Consistency of Visual Evoked Potential in Extraocular Manifestations of Behcet Disease and Impact of Corticosteroid Treatment.

To study the ability of pattern reversal visual evoked potentials (VEPs) to detect subclinical visual pathway pathologic assessment in Behcet disease (BD) and correlate VEP results in BD with disease activity and response to corticosteroid treatment. This study included 18 patients (36 eyes) with BD without recent ocular manifestations and 20 healthy controls (40 eyes). Clinical history was taken, and clinical examinations were done. Visual evoked potential recordings were performed by an electromyographic evoked machine for patients and controls. Corticosteroids were given to patients with extraocular activity, and VEP was repeated after clinical and laboratory improvement of the manifestations. p100 latency of VEP was prolonged in 8 patients (11 eyes) (44.4% of cases). Mean p100 latency showed statistically significant prolongations in BD group compared with the control group (106.7 ± 8.1 ms vs. 99.6 ± 1.9 ms) with P value < 0.001. There was a positive correlation between p100 latency and the disease activity score (r = 0.8673), whereas there was no correlation between p100 latency and the disease duration (r = 0.00072). Patients treated with corticosteroids showed statistically significant reduction in mean p100 latency after treatment (P < 0.001). Visual evoked potential may be a valuable tool for detecting subclinical neurologic affection in BD.

Delayed Visual Evoked Response is Linked to Vascular Endothelial Growth Factor and Autonomic Dysfunction in Type 2 Diabetes Mellitus

Aims: In this study, we aimed to assess the link between visual evoked potentials (VEP), angiogenic marker (VEGF) and autonomic function tests in type-2 diabetes mellitus (T2DM). Methods: Age-matched 86 male subjects (44 type-2 diabetics on treatment and 42 normal healthy volunteers) were recruited for this study. Body mass index (BMI), basal cardiovascular parameters, spectral analysis of heart rate variability (HRV), were assessed. Fasting blood glucose, insulin, HOMA-IR and VEGF were estimated. The independent association of the P100 latency of VEP with VEGF was determined by multiple regression analysis. Results: LF-HF ratio a marker of sympathovagal balance, increased significantly (p=0.0287) in diabetic group compared to the control group. Comparison of visual evoked potentials between controls and diabetic groups showed significant increase in latency of P100 of both the eyes (right eye p<0.0001, left eye p=0.0003) among the cases. There was significant increase (p=0.0091) in VEGF in diabetic subjects when compared to control. Also positive and significant correlation of P100 latency of VEP with VEGF is seen in diabetics. Conclusions: There is delayed latency of VEP and increased VEGF in type 2 diabetic people. The correlation between VEP and VEGF could indicate the probable role of angiogenesis leading to reduced integrity of the neural pathways in T2DM.

Meta-Analysis of Visual Evoked Potential and Parkinson's Disease.

Background Previous studies suggested that visual evoked potential (VEP) was impaired in patients with Parkinson's disease (PD), but the results were inconsistent. Methods We conducted a systematic review and meta-analysis to explore whether the VEP was significantly different between PD patients and healthy controls. Case-control studies of PD were selected through an electronic search of the databases PubMed, Embase, and the Cochrane Central Register of Controlled Trials. We calculated the pooled weighted mean differences (WMDs) and 95% confidence intervals (CIs) between individuals with PD and controls using the random-effects model. Results Twenty case-control studies which met our inclusion criteria were included in the final meta-analysis. We found that the P100 latency in PD was significantly higher compared with healthy controls (pooled WMD = 6.04, 95% CI: 2.73 to 9.35, P=0.0003, n=20). However, the difference in the mean amplitude of P100 was not significant between the two groups (pooled WMD = 0.64, 95% CI: −0.06 to 1.33, P=0.07) based on 10 studies with the P100 amplitude values available. Conclusions The higher P100 latency of VEP was observed in PD patients, relative to healthy controls. Our findings suggest that electrophysiological changes and functional defect in the visual pathway of PD patients are important to our understanding of the pathophysiology of visual involvement in PD.

Continuous Positive Airway Pressure Treatment May Improve Optic Nerve Function in Obstructive Sleep Apnea: An Electrophysiological Study.

Obstructive sleep apnea (OSA) is a sleep disorder frequently associated with optic nerve diseases. Moreover, untreated patients with severe OSA may show optic nerve dysfunction as documented by electrophysiological studies using visual evoked potentials (VEP). Because continuous positive airway pressure (CPAP) treatment has proved to restore the physiologic nocturnal breathing, thus preventing nocturnal hypoxemia and reducing inflammation, in this study we tested whether 1-year CPAP treatment may modify VEP responses in patients with severe OSA. VEP were recorded at baseline and after 1 year of CPAP treatment in 20 patients with severe OSA, divided in two groups on the basis of CPAP adherence, and compared to a healthy control group. Patients with good adherence to CPAP therapy (CPAP+; n = 10) showed VEP P100 amplitude significantly higher than patients with poor adherence to CPAP therapy (CPAP-; n = 10). Moreover, the CPAP+ group showed VEP responses similar to those in the control group (n = 26). Considering the mean difference of VEP responses between baseline and follow-up, the CPAP+ group showed a significant increase in VEP P100 amplitude and a significant decrease in VEP P100 latency compared to the CPAP- group. This study documented that CPAP therapy significantly improves VEP in patients with OSA who are adherent to the treatment. We hypothesize that CPAP treatment, minimizing the metabolic, inflammatory and ischemic consequences of OSA, may normalize the altered VEP responses in patients with OSA by restoring and preserving optic nerve function.

Comparing Colored and White-Black Visual Evoked Potentials in Multiple Sclerosis Patients.

We compared white-black (WB), white-red (WR), and black-red (BR) checkerboard stimulated visual evoked potentials (VEPs) in multiple sclerosis (MS) patients and aimed to evaluate if redcolored VEP is more sensitive than WB VEP for the diagnosis of optic neuritis (ON). Twenty-nine MS patients (21 females [72.4%]) and 35 healthy control subjects (24 females [68.6%]) were included in the study. Neurological and ophthalmological examinations were conducted for all subjects and VEP and optical coherence tomography (OCT) investigations were performed. A significant difference was found between MS patients and the control group for WB, WR, BR stimulated VEP P100 latencies and retinal nerve fiber length (RNFL) and ganglion cell complex (GCC) thicknesses, but there was no difference for WB, WR, and rb stimulated VEP amplitude values between the groups. There was no significant pathological difference between the eyes with an ON history in MS and eyes without an ON history in MS and control subjects after WB, WR, and BR stimulation (p=). The WB checkerboard stimulated VEP is an ample test for routine use; further studies are necessary regarding the utility of rb stimulated VEP in detecting subclinical ON.

Analysis of the Relationship Between Training Experience and Visual Sensory Functions in Athletes from Different Sports

Abstract Introduction. Gaining insight into the mechanisms and scope of possible adaptations of visual functions to the conditions determined by the demands imposed by sports training seems to be very interesting not only from a cognitive point of view, but also with respect to the practical applications of the findings of such investigations in the training process. The aim of the study was to assess the function of early visual processing in athletes representing different sports disciplines with varying training experience. Material and methods. The study involved 95 athletes practising football (n = 24), volleyball (n = 22), boxing (n = 26), and rowing (n = 23). The bioelectric function of the visual pathway was assessed based on recordings of visual evoked potentials (VEPs). The regions which were stimulated were the peripheral and central areas of the retina. During the test, we recorded the amplitude (μV) and latency (ms) of the P100 component of the VEP waveform for both monocular stimulation (for the dominant and non-dominant eye) and binocular stimulation. Results. Lower VEP P100 amplitude values were found for the peripheral and central locations for monocular and binocular viewing in more experienced volleyball players and rowers (p &lt; 0.05). In the case of boxers with greater training experience, a significantly lower (p &lt; 0.05) amplitude of the VEP P100 wave was observed in the central location in the dominant eye. However, we did not find significant differences (p &gt; 0.05) in intragroup variability in VEP P100 latency in relation to training experience in any of the sports disciplines examined. Conclusions. Training experience has an influence on the early stage of sensory processing with respect to neural activity. Training experience has been found to differentiate athletes in terms of the temporal parameters of the visual evoked potentials recorded in the current study only to a limited extent.

Alterations of the optic pathway between unilateral and bilateral optic nerve damage in multiple sclerosis as revealed by the combined use of advanced diffusion kurtosis imaging and visual evoked potentials

ObjectivesWe investigated changes in the optic tract and optic radiation in patients with multiple sclerosis (MS) by comparing unilateral and bilateral optic nerve damage assessed based on visual evoked potentials (VEPs) using advanced diffusion MR metrics. MethodsIn 21 MS patients, diffusion MRI was performed. Maps of fractional anisotropy, apparent diffusion coefficient (ADC), and mean kurtosis (MK) were computed. On the basis of the P100 latency in VEPs, the MS patients were divided into three groups: bilateral (n=7), unilateral (n=7), and no abnormality (n=7). Their optic tracts and optic radiations were analyzed with diffusion MRI-based fiber tracking. We also investigated the correlations between diffusion parameters and VEPs (n=21). ResultsIn the optic tract, the diffusion changes in each of the three groups showed step-like changes. The diffusion changes in the optic radiations of the unilateral group were similar to those in the normal VEP group. Only the bilateral group showed significantly higher ADC and lower MK relative to the other two groups (P<0.05, Steel–Dwass multiple-comparison test). A significant positive correlation between VEP latency and ADC and a significant negative correlation between VEP latency and MK were observed (P<0.01, Spearman's correction). ConclusionsWe first evaluated the relationship between VEPs and DKI and concluded that the lateral geniculate nucleus may compensate for unilateral damage in the pre-geniculate optic pathway via neural plasticity.

Peripheral and Central Nervous System Involvement in Recently Diagnosed Cases of Hypothyroidism: An Electrophysiological Study.

Background:Hypothyroidism, one of the most common endocrine disorders, may induce neurological abnormalities at an early stage of the disease.Aim:The study was designed to assess the electrophysiological alterations of some selected variables of nerve conduction, brainstem auditory evoked potentials (BAEPs), and visual evoked potentials (VEPs) in hypothyroid patients.Subjects and Methods:Sixty patients of newly diagnosed hypothyroidism and an equal number of age-matched controls were selected for the study. Nerve conduction studies that included parameters as latencies, conduction velocities, and amplitude of motor nerves, i.e., median, ulnar, common peroneal, tibial nerve, and sensory nerves, i.e., median and sural nerves was performed in both hypothyroid patients and controls. Further, BAEPs and VEPs of all the patients were done. The data were compiled and statistically analyzed using Student's unpaired t-test to observe any electrophysiological alterations in hypothyroid patients as compared to healthy controls.Results:On comparative evaluation, statistically significant increase in latency of median, ulnar, tibial, and sural nerves; decrease in conduction velocities of all the tested nerves and decrease in amplitude of median, tibial, and sural nerves was observed in hypothyroid patients. Statistically significant increase in latencies, interpeak latencies, and decrease in amplitudes of BAEP waves and statistically significant increase in P100 latency of VEP was seen in hypothyroid patients.Conclusion:The results of our study suggest that peripheral and central neuropathy develops in patients of hypothyroidism at an early stage of disease and the electrophysiological investigations of such patients can help in timely detection and treatment of neurological disorders that occur due to thyroid hormone deficiency.

Evaluation of the retinal nerve fiber layer thickness and its relation to visual evoked potentials in multiple sclerosis

PurposeTo evaluate the retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (OCT) in Lithuanian patients with multiple sclerosis (MS) and to assess the relationship between RNFL thickness and visual evoked potentials (VEP).MethodsFrom 2013 till 2014 a prospective study involving 71 patients with multiple sclerosis was conducted in Vilnius University Hospital Santariškių Clinic Center of Neuroscience and Eye Diseases. The epidemiological, clinical, laboratory and instrumental data was assessed: gender, age, oligoclonal bands, IgG index in cerebrospinal fluid (CRF), visual evoked potentials (VEP), OCT. RNFL and papilomacular bundel (PMB) thicknesses were performed with SD‐OCT.ResultsThe distribution of gender for patients with MS was as follows: men n = 22 (31%), women n = 49 (69%); average age −40.7 ± 10.7 years. OCT results were as follows: RNFL average thickness: right eye 85.5 ± 15.6 μm, left eye 86.3 ± 13.2 μm. According to the t‐test: the upper nasal (NS) segment averages of right and left eyes differed statistically significant −6.6 ± 14.7 μm (p &lt; 0.05). There was significant negative correlation between VEP P100 latency and RNFL thickness of the right eye TI segment (r = −0.57; p = 0.01) and the left eye PMB segment (r = −0.52; p = 0.02). The most damaged segment was the temporal (T) one: right eye 84.5% (n = 60), left eye −90.1% (n = 64). RNFL of both eyes revealed statistically significant mean differences with the IgG index.ConclusionsThe most vulnerable segment of the retina is the temporal. If VEP gets prolonged thinning of RNFL is also observed. The CSF index is increased by immunologically more active multiple sclerosis. We think that more active form of MS may be associated with retinal segments violation. Hence we may conclude that RNFL thinning could be related with irreversible progression of the disease.

Amiodarone neurotoxicity: the other side of the medal

Abstract The efficacy of amiodarone is tempered by its toxicity, with 50% of long-term users discontinuing the drug. The non-cardiac side effects of amiodarone may involve central and peripheral nervous system. We studied two patients treated with amiodarone for 46 and 15 months respectively. Both patients exhibited progressive distal extremity weakness, impaired perception, loss of deep reflexes. Electrophysiology identified a widespread, sensorimotor polyneuropathy with features of axonal loss and demyelination. Visual evoked potentials (VEPs) showed prolonged P100 latency bilaterally in absence of visual symptoms or brain magnetic resonance imaging (MRI) abnormalities. Extensive laboratory examinations excluded known causes of peripheral neuropathies. At 21 months after amiodarone withdrawal, P100 latency of case 1 VEPs returned to normal, whereas polyneuropathy continued to progress. In the second patient neuropathy has worsened similarly over 2 years whereas P100 latency of VEPs recovered to normal within 7 months after withdrawal of amiodarone. These findings may suggest different mechanisms of toxicity, which could be due to amiodarone pharmacokinetic and its metabolite effects on the peripheral nerves, as opposed to the optic nerve. We emphasize that use of amiodarone needs monitoring of patients at risk of development side effects.

Effects of Visual Rehabilitation on a Child With Severe Visual Impairment

We examined the effects of visual rehabilitation, including a chromatic luminance discrimination program and a fixation training program, on a 6-yr-old boy with severe visual impairment. Single-subject ABA and AB designs were used. The programs were conducted 2×/wk and included 6 to 7 sessions for the baseline phase and 10 to 11 sessions for the intervention phase. Play was integrated into the visual training programs. Goggle visual evoked potential (VEP) testing was used to evaluate neural activity in the primary visual cortex. Correct responses increased and response times were shortened after training in luminance discrimination. The total and maximum fixation time also improved, as did P100 latency and amplitude of VEPs. While walking, the boy was able to detect obstacles he had not noticed before training. The results indicate the value of visual training and the possibility of brain plasticity in a child with severe visual impairment.

Abstract TP441: Neurovascular Coupling is Impaired in Cerebral Amyloid Angiopathy

Introduction: Cerebral amyloid angiopathy (CAA) is marked by accumulation of vascular beta-amyloid which is toxic to smooth muscle cells. An animal study and a pilot study in humans suggest decreased vasodilation in CAA. We studied patients with CAA and matched controls to determine whether neurovascular coupling is impaired in CAA. Methods: Patients with CAA and controls underwent task-related fMRI with a visual task (viewing a flashing alternating checkerboard pattern) or a motor task (tapping the fingers of the dominant hand) using a block design, and visual evoked potentials (VEPs). CAA patients were diagnosed by Boston criteria and had normal corrected visual acuity, no visual field deficits and no paresis of the dominant arm. Controls were recruited by community advertising and were matched by gender and age (±5 years) to CAA cases. Results: Eighteen CAA patients (12 M, 6F; 72±7 yrs) and eighteen controls (12 M, 6F; 70±7 yrs) were studied. For the visual task, CAA patients had reduced activity in the occipital lobe (Figure) and lower amplitude of the BOLD response vs. controls (28% reduced, p=0.005). By contrast, for the motor task CAA patients had a similar response of the primary motor cortex vs. controls (9.6% reduced BOLD response, p=0.53). VEP P100 latencies and amplitudes did not differ between CAA and controls (p=0.49 and p=0.74). Lower visual cortex BOLD amplitudes were correlated with greater white matter lesion volumes in CAA (r=-0.66, p=0.003). Conclusions: Neurovascular coupling is impaired in the occipital lobe in CAA. BOLD signal amplitudes are reduced despite normal evoked potentials, suggesting impaired vasodilation. The association with white matter lesion volume raises the possibility that impaired vasodilation may be involved in the pathogenesis of these lesions. BOLD responses in the primary motor cortex in CAA were not reduced, likely reflecting the known posterior predominance of CAA with lesser involvement of the frontal lobe.

Progressive Degeneration of the Retinal Nerve Fiber Layer in Patients with Multiple Sclerosis

To quantify changes in the retinal nerve fiber layer (RNFL) of patients with multiple sclerosis (MS) over 3 years and to evaluate whether treatment protects against RNFL degeneration. Ninety-four MS patients and 50 healthy subjects were followed-up over 3 years. All subjects underwent a complete ophthalmic examination, which included assessment of visual acuity (Snellen chart), color vision (Ishihara pseudoisochromatic plates), visual field examination, optical coherence tomography (OCT), and visual evoked potentials (VEPs). All patients were reevaluated at 12, 24, and 36 months to quantify changes in the RNFL. Changes were detected in RNFL thickness at the 36-month follow-up. Significant decreases (P < 0.05, t-test) were observed in the mean, superior, inferior, and temporal RNFL thicknesses, and macular volume provided by OCT, and in the P100 latency of VEP of the MS group, but only in the mean and inferior RNFL thicknesses of the healthy control group. Greater changes in the superior and inferior RNFL thicknesses during follow-up were detected in the MS group. Differences between treatments were not detected, but untreated patients had higher degeneration in the mean and superior RNFL thicknesses during the follow-up (P = 0.040 and P = 0.19, respectively). Progressive axonal loss can be detected in the optic nerve fiber layer of MS patients. Analysis of the RNFL by OCT can be useful for evaluating MS progression and efficacy of treatment as a neuroprotective factor against axonal degeneration.

Current electrophysiology in ophthalmology

To summarize current technique, indications, and pitfalls of electrophysiologic testing used in ophthalmology. Visual evoked potentials (VEPs) may be useful as an objective measurement of refractive error in complicated patients. VEP P100 latency was found superior to color vision and visual field in early stages of hydroxychloroquine maculopathy. VEP results can be predictive of visual recovery in traumatic optic neuropathy. Multifocal electroretinogram (ERG) or VEP can provide an objective assessment of visual field defects not yet present on automated perimetry in patients with glaucomatous and nonglaucomatous optic neuropathies. In patients with intraocular lymphoma, reduced amplitudes of all ERG components can be recorded, with the b-wave amplitude being most significantly affected. Various visual electrophysiologic tests are useful to the ophthalmologist, each with different indications. The flash ERG is most useful in diffuse retinal disorders, whereas the multifocal ERG is superior in localized retinal disease. VEPs can be valuable in diagnosing optic neuropathies, nonorganic visual loss, and assessing visual function in infants or children.

Evaluation of visual field parameters in patients with chronic obstructive pulmonary disease

To evaluate the effects of chronic obstructive pulmonary disease (COPD) on retina and optic nerve. Thirty-eight patients with COPD and 29 healthy controls, totally 67 subjects, were included in the study. Visual evoked potentials (VEP) and visual field assessment (both standard achromatic perimetry (SAP) and short-wavelength automated perimetry (SWAP)) were performed on each subject after ophthalmological, neurological and pulmonary examinations. Mean deviation (MD), pattern standard deviation (PSD) and corrected pattern standard deviation (CPSD) were significantly different between patient and control groups as for both SAP and SWAP measurements (p = 0.001, 0.019, 0.009 and p = 0.004,0.019, 0.031, respectively). Short-term fluctuation (SF) was not statistically different between the study and the control groups (p = 0.874 and 0.694, respectively). VEP P100 latencies were significantly different between patients with COPD and the controls (p = 0.019). Chronic obstructive pulmonary disease is a systemic disease, and hypoxia in COPD seems to affect the retina and the optic nerve.

Degeneration of retinal nerve fiber layer in patients with multiple sclerosis. Prospective study with three years follow‐up

AbstractPurpose To quantify changes over three years in the retinal nerve fiber layer (RNFL) of patients with multiple sclerosis (MS) and to evaluate if treatments are a protector factor of CFNR degeneration.Methods One hundred and eighty‐eight eyes of 94 MS patients were followed‐up during 3 years. All patients underwent a complete ophthalmic examination that included assessment of visual acuity (Snellen chart), colour vision (Ishihara pseudoisochromatic plates), visual field examination, optical coherence tomography (OCT) and visual evoked potentials (VEP). All patients were re‐evaluated in a period of 12, 24 and 36 months in order to quantify the changes in the retinal nerve fiber layer (RNFL).Results Changes were obtained in the RNFL thickness with a 36‐month follow‐up. There were significant decreases (P&lt;0,05 , t test) in the mean, superior, inferior , nasal and temporal RNFL thickness and macular volume provided by OCT, and in P100 latency of VEP. The greater differences were obtained in the superior and inferior RNFL thickness. Differences were not found between treatments, but untreated patients showed higher degeneration during follow‐up in the mean and superior RNFL thickness (p= 0,045 y p=0,024 respectively).Conclusion Progressive axonal loss can be detected in the optic nerve of MS patients. The analysis of RNFL in OCT can be useful to evaluate MS progression and efficacy of treatments in reduction of axonal degeneration.