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AIM: To study the role of nitric oxide ( NO ) and γ-aminobutyric acid ( GABA) in the formation of amblyopia by establishing 2 different types of amblyopic models.METHODS:A total of 18 aged 3-week kittens were randomly divided into monocular deprivation, strabismus and normal groups. All types of amblyopia were developed in the experimental eyes that were detected by P-VEP 12wk later. The cats were killed and the immunocytochemistry staining method were applied to observe under the light microscope the changes of distribution and positive cells areas of NO and GABA across the amblyopic retinal, compared to that from the normal cats of identical age. RESULTS: The P-VEP showed that the amplitude of wave P1 was lower (P CONCLUSION:The NO and GABA play an important role in the formation of amblyopia in the level of retinal.
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OBJECTIVE:To investigate the clinical efficacy of levodopa combined with comprehensive therapy for ametropic amblyopia children and teenagers and its effeets on pattern visual evoked potential(P-VEP)and visual function. METHODS:70 pa-tients(80 eyes)with ametropic amblyopia were randomly divided into observation group(35 cases,40 eyes)and control group(35 cases,38 eyes). Control group received comprehensive therapy as wearing correctional glasses,occlusion therapy and visual stimu-lation training;observation group additionally received levodopa 0.125(d1-3)-0.25 g/time,bid,on the basis of control group for 6 months. Therapeutic efficacy,P-VEP,Visual sensitivity and visual function were compared between two groups,and the occur-rence of ADR was recorded. RESULTS:The effective rate of observation group(92.50%)was significantly higher than that of con-trol group(76.32%),with statistical significance(P0.05). CONCLUSIONS:Levodopa combined with comprehensive therapy can improve the function of visual central neurons,and improve visual acuity and binocular stereo vision functions so as to improve therapy efficacy.
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PURPOSE: To compare the characteristics of the pattern visual evoked potential (PVEP) in patients with severe visual loss and normal controls, and to demonstrate the range of PVEP parameters in normal Koreans. METHODS: The patients were divided into three groups according to visual acuity: group 1, ranging from no light perception to less than 0.02; group 2, ranging from 0.02 to 0.1; and group 3, ranging from 0.125 to 0.25. Group 4 was established as a healthy control group. The 95% confidence intervals (CIs) of the PVEP parameters were calculated for group 4. The PVEP parameters were compared among these four groups, and the amplitudes were evaluated with respect to the 95% CIs. We used the area under the curve to integrate the sensitivity and the specificity of the PVEP parameter quantitative values (7.01 to 9.57 microV and 6.75 to 10.11 microV). RESULTS: A total of 101 eyes were investigated. The 95% CIs of the P100 and N135 amplitudes of group 4 were 7.01 to 9.57 microV and 6.75 to 10.11 microV, respectively. The amplitudes of P100 and N135 were significantly higher in group 4 (p < 0.001). The P100 and N135 amplitude were below the 95% CI in all group 1 patients. The area under the curve of the P100 amplitude was the highest (0.789). CONCLUSIONS: No legally blind patient in the present study exhibited a value within the 95% CI of the controls. The P100 amplitude may be the best parameter for defining blindness in patients.
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Adult , Female , Humans , Male , Middle Aged , Young Adult , Blindness/physiopathology , Evoked Potentials, Visual , Retrospective Studies , Vision, Low/physiopathology , Visual AcuityABSTRACT
PURPOSE: To compare the characteristics of the pattern visual evoked potential (PVEP) in patients with severe visual loss and normal controls, and to demonstrate the range of PVEP parameters in normal Koreans. METHODS: The patients were divided into three groups according to visual acuity: group 1, ranging from no light perception to less than 0.02; group 2, ranging from 0.02 to 0.1; and group 3, ranging from 0.125 to 0.25. Group 4 was established as a healthy control group. The 95% confidence intervals (CIs) of the PVEP parameters were calculated for group 4. The PVEP parameters were compared among these four groups, and the amplitudes were evaluated with respect to the 95% CIs. We used the area under the curve to integrate the sensitivity and the specificity of the PVEP parameter quantitative values (7.01 to 9.57 microV and 6.75 to 10.11 microV). RESULTS: A total of 101 eyes were investigated. The 95% CIs of the P100 and N135 amplitudes of group 4 were 7.01 to 9.57 microV and 6.75 to 10.11 microV, respectively. The amplitudes of P100 and N135 were significantly higher in group 4 (p < 0.001). The P100 and N135 amplitude were below the 95% CI in all group 1 patients. The area under the curve of the P100 amplitude was the highest (0.789). CONCLUSIONS: No legally blind patient in the present study exhibited a value within the 95% CI of the controls. The P100 amplitude may be the best parameter for defining blindness in patients.
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Young Adult , Blindness/physiopathology , Evoked Potentials, Visual , Retrospective Studies , Vision, Low/physiopathology , Visual AcuityABSTRACT
Background: Optic pathway involvement in multiple sclerosis is frequently the initial sign in the disease process. In most clinical applications, pattern visual evoked potential (PVEP) is used in the assessment of optic pathway involvement. Objective: To question the value of PVEP against color vision assessment in the diagnosis of subclinical optic pathway involvement. Materials and Methods: This prospective, cross-sectional study included 20 multiple sclerosis patients without a history of optic neuritis, and 20 healthy control subjects. Farnsworth-Munsell (FM) 100-Hue testing and PVEPs to 60-min arc and 15-min arc checks by using Roland-Consult RetiScan® system were performed. P100 amplitude, P100 latency in PVEP and total error scores (TES) in FM 100-Hue test were assessed. Results: Expanded Disability Status Scale score and the time from diagnosis were 2.21 ± 2.53 (ranging from 0 to 7) and 4.1 ± 4.4 years. MS group showed significantly delayed P100 latency for both checks (P < 0.001). Similarly, MS patients had significantly increased total error scores (TES) in FM-100 Hue (P < 0.001). The correlations between TESs and PVEP amplitudes / latencies were insignificant for both checks (P > 0.05 for all). 14 MS patients (70%) had an increased TESs in FM-100 Hue, 11 (55%) MS patients had delayed P100 latency and 9 (45%) had reduced P100 amplitude. The areas under the ROC curves were 0.944 for FM-100 Hue test, 0.753 for P100 latency, and 0.173 for P100 amplitude. Conclusions: Color vision testing seems to be more sensitive than PVEP in detecting subclinical visual pathway involvement in MS.
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Aim To observe the effects of the L-dopa methyl ester (LDME) on the pattern visual evoked potentials (P-VEP) and the expression of c-fos mRNA in neurons of the visual cortex of kittens with strabismic amblyopia, and explore the therapeutic effect of L-dopa methyl ester on amblyopia and its action mechanism.Methods 30 normal kittens were randomly divided into 6 groups: low dose of L-dopa methyl ester (20 mg·kg~(-1)), medium dose of L-dopa methyl ester (40 mg·kg~(-1)), and high dose of L-dopa methyl ester (80 mg·kg~(-1)),positive control (L-dopa 40 mg·kg~(-1)),normal control, and model control group.The surgery for producing iatrogenic convergent strabismus was performed on 4 weeks old kittens(normal control group excluded). After the confirmation of the development of amblyopia by pattern visual evoked potential,L-dopa methyl ester,L-dopa and normal saline were given to the corresponding animals, respectively. The P-VEP of amblyopia eyes was observed after one month, and the technique of in situ hybridization was used to detect the expression of c-fos mRNA.Results L-dopa methyl ester could reduce obviously the length of P100 peak latency of the cat strabismic amblyopes, and increase the amplitude of P100. The positive staining cells of strabismic cat visual cortex were less than those of normal cats, whose difference was significant (P<0.01).Positive staining cells in the treatment group were significantly increased when compared with that of the model group (P<0.01).Conclusion L-dopa methyl ester can significantly improve the conduction and sensory function in the model of strabismic amblyopia cats. The mechanism may be related to the increased amount of L-dopa methyl ester into the cerebral cortex and regulation of the expression of c-fos mRNA.
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PURPOSE: To analyze the correlation between RNFL thickness changes measured by OCT and hemifield pattern VEP in hemianopic visual field loss. METHODS: Twelve eyes of six patients with hemianopia were studied. Two patients had bitemporal hemianopia caused by chiasmal tumor, one patient had inferior hemianopia caused by traumatic optic neuropathy, and three patients had homonymous hemianopia caused by occipital lobe lesions. The retinal nerve fiber layer thickness around the optic disc was measured by optical coherence tomography (OCT) and visual pattern evoked potentials were measured using hemifield stimulations. RESULTS: Normal eyes of traumatic optic neuropathy patients were excluded from the analysis. The retinal nerve fiber layer thickness as measured by OCT corresponded to the visual field defect in 9 of 11 eyes (81.8%) and the hemifield pattern VEP response corresponded to visual field defect in 7 of 11 eyes (63.6%). CONCLUSIONS: RNFL thickness measurement by OCT and hemifield PVEP are useful in evaluation of patients with hemianopia. However, they should be performed with caution, and compared with various clinical examinations because of their incomplete correlation with visual field defects.