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BackgroundSweep pattern visual evoked potential(SPVEP) acuity,as an objective detective technique of visual function,can be used to measure visual acuity in children and uncooperative adults.Recent studies have shown that the amplitude-logarithm of the visual angle (A-LogVA) function regression method was more accurate than the amplitude-spatial frequency (A-SP)function regression method in evaluating SPVEP acuity.Objective This study was to explore the clinical use of SPVEP acuity in visual developing children and compare the evaluating the SPVEP acuity of children between A-SP function regression method and A-LogVA function regression method.Methods Twenty-six eyes of 26 asthenopic children with age range of 3-12 years and 31 age-matched normal children were enrolled in this study.SPVEP acuity was recorded with GT-2000 NV ( GUOTE MEDICAL APPARATUS LTD,China) using sinusoidally modulated horizontal gratings of 10 different spatial frequencies from 0.99 to 12.89 cpd as stimulus.The responses were averaged and displayed through discrete Fourier transformations (DFT) on the monitor display.SPVEP acuity was estimated by using both the SPVEP A-SP function regression method and the SPVEP A-LogVA function regression method.The LogMAR chart was used to acquire LogMAR visual acuity.ResultsIn the normal group,the correlation coefficient between LogMAR visual acuity and acuity calculated by the A-SP function regression method was 0.600 (P＜0.01).The correlation coefficient between LogMAR visual acuity and acuity calculated by the A-LogVA function regression method was 0.733 ( P＜0.01 ).The ANOVA of the LogMAR acuity and the SPVEP acuity calculated from the A-SP function regression method and A-LogVA function regression method were 113.173 (P＜0.01 ),which indicated that there were significant difference among all of subjects.The differences of the mean values of LogMAR visual acuity and the SPVEP acuity calculated from the A-SP function regression method and A-LogVA function regression method were respectively 0.40±0.02,0.26 ±0.02 and 0.14 ± 0.02.In the amblyopia group,the correlation coefficient between LogMAR visual acuity and acuity calculated by the A-SP function regression method was 0.134 (P =0.515 ).The correlation coefficient between LogMAR visual acuity and acuity calculated by the A-LogVA function regression method was 0.456 ( P＜0.05 ).The ANOVA of the LogMAR acuity and the SPVEP acuity calculated from the A-SP function regression method and A-LogVA function regression method were 3.433 (P＜0.05),indicating that there were significant difference among all of subjects.The differences of the mean values of LogMAR visual acuity and the SPVEP acuity calculated from the A-SP function regression method and A-LogVA function regression method were 0.07±0.05,0.12±0.05 and 0.05 ±0.01 respectively.Conclusions SPVEP can evaluate the visual acuity in children,although SPVEP acuity may overestimate or underestimate acuity in comparison with different LogMAR visual acuities.The amplitude-LogVA function regression method is more accurate in extrapolating SPVEP acuity.
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Background Sweep pattern visual evoked potential (SVEP) is an objective method of visual test.There is a clear correlation between SVEP acuity and subjective vision,but they are not identical.Recent studies showed that new regression method can improve the accuracy of SVEP acuity. Objective This trial was to investigate and compare the outcome between amplitude-spatial frequency (A-SP) regression method and amplitudelogVA (A-logVA) regression method in extrapolating the SVEP acuity.Methods SVEP was recorded in 113 eyes of 64 subjects using GT-2000 ( Guo Te,China) with the gratings of 10 different spatial frequency from 0.99 to 12.89 cpd as stimulus.The 1 13 eyes included cataract,glaucoma,corneal disease,optical neuropathy,retinal disease,ocular trauma,refractive error and normal eyes.The correlation were analyzed of SVEP acuity,decimal visual acuity and LogMAR visual acuity.The response were averaged and DFT on the monitor display.SVEP acuity was calculated by extrapolating 0 response amplitude.Results The correlation indices of decimal visual acuity curves obtained by the A-logVA function was 0.663,and that obtained by the A-SP function was 0.705.The positive correlation was seen between subjective decimal visual acuity and A-logVA decimal visual acuity (r =0.540,P＜ 0.01 ) and between subjective decimal acuity and decimal acuity calculated by the A-SP regression method (r=0.620,P＜0.01 ).SVEP decimal acuity calculated by the A-SP function regression method was significantly different from the that calculated by the A-logVA function regression method (Z =-8.688,P＜0.01 ).And the correlation indices of LogMAR visual acuity curves obtained by the A-logVA function was 0.733 and that obtained by the A-SP function was 0.715.The positive correlation was found between the subjective LogMAR acuity and that calculated by the A-SP regression method (r=0.700,P＜ 0.01 ) and between the subjective LogMAR acuity and LogMAR acuity calculated by the A-logVA regression method (r=0.710,P＜0.01 ).SVEP LogMAR acuity from A-SP function regression method was significantly different from the LogMAR acuity from A-logVA function regression method (Z=-8.748,P＜0.01 ).No significant differences of VA LogMAR were found in gender,eyes,type of disease and age(x2 =2.171,P=0.338;x2 =0.976,P=0.614;x2 =6.032,P=0.420;x2 =14.720,P=0.257 ).Conclusions SVEP can obtain the visual outcome in human.The amplitude-logVA function regression method is more accurate in extrapolating SVEP acuity.
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Background Intravitreal injection of triamcinolone acetonide (TA) can effectively eliminate central vein occlusion macular edema and improve visual acuity, and photopic negative response (PhNR) can reflect the inner retinal function of RGCs and their axons. It is possible there is a correlation between these two observations.Objective This study was to evaluate the changes of PhNR of flash electroretinogram (F-ERG) after intravitreal injection of TA for macular edema in central retinal vein occlusion ( CRVO ). Methods Thirteen eyes of 12 patients with macular edema caused by CRVO received an injection of 0. 1 ml (4 rg) of TA. PhNR,visual acuity and retinal thickness of macular area were assessed with Roland RETI scan 3. 15 system,decimal visual chart and Stratus optical coherence tomography (OCT) before and 4 weeks after the administration of TA. Written informed consent was obtained from each subject before any medical procedure. Results Visual acuity was improved in 12 eyes and stable in 1 eye 4 weeks following the intravitreal injection of TA. OCT showed that the retinal thickness of the macular area was reduced ;meanwhile,elevation of the amplitude of PhNR also was seen in the F-ERG after the administration of TA in comparison with before the administration of TA. The calculated results determined that the visual acuities were 0. 32t0. 12 and 0. 48±0. 09 (t=6. 325 ,P=0. 000) ,and the retinal thickness values of the macular area were (459.46± 131.31 ) μm and ( 297.54 ±43.31 ) μm ( t = 5.961, P = 0. 000 ), and the average amplitude of PhNR were ( 80. 23±22.96 ) μV and (61.28 ±20. 16 ) μV ( t = 4. 438, P = 0. 001 ) before and after the intravitreal injection of TA, respectively,showing significant differences. No significant correlation was found between PhNR amplitude and retinal thickness of the macular area both before and after the administration of TA ( before: r = 0. 587, P = 0. 035; after:r=-0. 011 ,P = 0. 971 ). Conclusion PhNR can be used for evaluating the status of inner retina after intravitreal injection of TA for macular edema of CRVO.