ObjectiveTo study whether the pattern visual evoked potential (P-VEP) under different spatial frequency in patients with multiple sclerosis (MS) is different from normal people. MethodsP-VEP examination under high (15') and low (60') spatial frequency was performed on 18 MS patients (36 eyes) treated in our department from September 2011 to April 2012 and 20 normal volunteers (40 eyes). Then, we analyzed the difference between the two groups under the above-mentioned two kinds of spatial frequency. ResultsThe latency of P100 of P-VEP under high spatial frequency in MS patients was (120.50±13.04) ms which was significantly different from (109.21±5.38) ms of normal volunteers (P < 0.05). The latency of P100 of P-VEP under low spatial frequency in MS patients was (109.57±12.87) ms, which was also significantly different from (103.31±5.45) ms of normal volunteers (P < 0.05). The amplitude of P100 of P-VEP under high spatial frequency in MS patients was (9.17±5.69)μV and it was significantly lower than that[(15.69±8.45)μv] of normal volunteers (P < 0.05). The amplitude of P100 of P-VEP under low spatial frequency in MS patients was (11.93±16.75)μV and it was not significantly different from normal volunteers[(13.47±9.24μV)]. Based on different corrected vision, the MS patients were divided into two groups (vision≥1.0 and vision < 1.0). For patients with vision≥1.0, the latency of P100 and the amplitude of P100 of P-VEP under high spatial frequency was (113.43±8.28) ms and (12.94±5.46)μV; the latency of P100 and the amplitude of P100 of P-VEP under low spatial frequency was (111.13±11.50) ms and (11.57±5.60)μV. For patients with vision < 1.0, the latency of P100 and the amplitude of P100 of P-VEP under high spatial frequency was (126.69±13.49) ms and (5.87±3.43)μV; the latency of P100 and the amplitude of P100 of P-VEP under low spatial frequency was (108.26±14.11) ms and (12.24±5.82)μV. There was no significant difference in the latency and amplitude of P100 under low spatial frequency between the two groups with different corrected vision (P > 0.05), but the latency and amplitude of P100 under high spatial frequency were both significantly different between those two groups (P < 0.05). ConclusionsCompared with normal people, MS patients feature latency delay and amplitude reduction of the P-VEP, which was more severe under high spatial frequency. P-VEP under high spatial frequency may become an important evidence to evaluate visual function of MS patients.
ObjectiveTo use flash electroretinogram (F-ERG) and optical coherence tomography (OCT) to examine patients with primary retinitis pigmentosa (RP), and analyze the specificity of the disease on F-ERG and OCT. MethodsThirty-seven patients (74 eyes) diagnosed with primary retinitis pigmentosa in the Department of Ophthalmology, West China Hospital between September 2013 to October 2014 and 38 normal volunteers (76 eyes) were included in this study. F-ERG and OCT examinations were performed on all the patients. Then, we analyzed the differences between the two groups of subjects. ResultsFor RP patients undergoing P-ERG examination with the dark adaptation of 0.01 ERG, the latency of b wave was (73.24±6.42) ms and the amplitude of b wave was (22.87±22.48) μV; when dark adaptation of 3.0 ERG was adopted, the latency of a wave was (24.57±6.30) ms, the amplitude of a wave was (35.45±25.54) μV, the latency of b wave was (48.19±8.18) ms, and the amplitude of b wave was (119.47±50.89) μV; with the light adaptation of 3.0 ERG, the latency of a wave was (21.01±4.86) ms, the amplitude of a wave was (12.59±13.43) μV, the latency of b wave was (38.43±5.00) ms, and the amplitude of b wave was (27.19±38.12) μV. For normal volunteers undergoing F-ERG examination with the dark adaptation of 0.01 ERG, the latency of b wave was (72.63±3.49) ms and the amplitude of b wave was (86.36±21.57) μV; when the dark adaptation was 3.0 ERG, the latency of a wave was (22.88±1.62) ms, the amplitude of a wave was (210.74±43.57) μV, the latency of b wave was (42.59±2.60) ms, and the amplitude of b wave was (398.29±62.42) μV; when the light adaptation of 3.0 ERG was adopted, the latency of a wave was (16.61±0.87) ms, the amplitude of a wave was (54.26±19.64) μV, the latency of b wave was (33.29±1.11) ms, and the amplitude of b wave was (176.98±63.44) μV. There were no significant differences between the two groups when dark adaptation ERG was 0.01 (P=0.48), but for other adaptations, there were significant differences in the latency and amplitude of a and b wave between the two groups (P<0.05). The results of OCT showed that the retinal thickness of the RP patients with a range of 1 mm diameter centered on macular center concave was (218.66±74.14) mm, 3 mm diameter was (275.03±47.85) mm, and 6 mm diameter was (247.37±46.44) mm. For normal volunteers, OCT showed that the retinal thickness with a 1 mm range centered on macular center concave was (250.38±15.79) mm, 3 mm was (323.64±17.26) mm, and 6 mm was (283.44±12.50) mm. The differences between the two groups were statistically significant for each range (P<0.01). ConclusionFor patients with RP, F-ERG shows latency delay and amplitude decrease for each response, while OCT displays a thinning thickness of macular fovea. Therefore, F-ERG and OCT can not only effectively evaluate the functions of macular and the surrounding retina, but can also be used as an effective method for the diagnosis of RP.