摘要
目的 :初步分析正常人眼多焦视网膜电图 (m ERG)测量值 ,并探讨正常眼视网膜后极部不同部位的电生理功能。方法 :对 19例 (2 5眼 )散瞳正常眼作多焦视网膜电图检查 ,记录 6 1个部位反应波形图 ,分析视网膜后极部不同区域的a波 (第 1个负波 )和b波 (第 1个正波 )的潜伏期、振幅值及振幅密度。结果 :视网膜后极部中心环 (第 1环 )振幅密度为最高 ,a波为 (33.92± 18.95 )nV/deg2 ,b波为 (6 8.78±19.84 )nV/deg2 ,随着离心度的增加 ,各振幅密度逐渐下降 ,差异有显著性 (P <0 .0 1)。a波及b波潜伏期、振幅及振幅密度在四个象限的差异均无显著性 (P >0 .0 5 )。结论 :多焦视网膜电图能客观、定位、定量地测定视网膜后极部不同部位的视功能 。
Objective:To investigate normal values for multifocal electroretinograms(m ERG) obtained from normal subjects,and to analyze the changes in electrophysiological function in a central visual field of about 30 degrees in diameter. The posterior retinal electrophysiological function was also analyzed with this m ERGs technique.Methods:m ERGs were recorded from 25 normal eyes of 19 normals with no known systemic or eye diseases(age 36.2±20.7 years) by a RETI Scan 3.15 multifocal electrogram system(Roland Company,Germany) according to the technique used by Bearse et al. 61 equal size hexagonal stimulus elements with average light intensities of 120 cd/m 2 were used and the recordings were evaluated. The external gain was 100000 with a low cutoff at 10Hz and a high cutoff at 100 Hz(using a response filter bandwidth setting of 10～100 Hz). A jet contact electrode was used and the test distance was adjusted to 25 cm. The stimulus field was 30 degrees in diameter when subjects looked at the 3 mm dot fixation point on a 21 inch black and white monitor. For all subjects,pupils were dilated more than 7 mm in diameter before taking m ERGs. Eight segments were recorded,with each segment lasting 47 seconds in duration. The first order kernal was used to calculate amplitude,latencies and amplitude densities in 61 retinal locations on a central visual field of about 30 degrees. The first negative wave(a wave) and positive wave(b wave) of the m ERGs were measured. For data analysis the 61 local responses were grouped into two configurations:(A) nasal superior or inferior,temporal superior or inferior and (B) five concentric rings(ring 1～ring 5) centered on the fovea. Amplitudes,latencies and amplitude intensities for the two configurations were calculated and compared. The excel t test was used for statistical purposes.Results:Of the 25 normal eyes,the sum values of the a wave were(31.92±7.11)μV for amplitude and (20.43±1.03)ms for latency. The sum values of the b wave were(60.28±13.50)μV for amplitude and (31.92±1.26)ms for latency. The latencies of the a wave in rings 1 to 5 were(18.29±2.87)ms,(16.84±2.13)ms,(16.67±2.07)ms,(17.02±1.98)ms and (16.38±3.15)ms. And their amplitudes were(0.36±0.14)μV, (0.31±0.11)μV,(0.32±0.09)μV,(0.30±0.08)μV and (0.31±0.09)μV,respectively,and their amplitude densities were(33.92±18.95)nV/deg 2,(24.82±15.32)nV/deg 2,(20.54±13.12)nV/deg 2,(17.07±12.23)nV/deg 2 and (15.71±11.74)nV/deg 2,respectively. For the b wave,the values of latencies in rings 1 to 5 were(34.50±3.41)ms,(33.15±2.06)ms,(32.60±1.36)ms,(32.21±1.25)msand (31.94±1.14)ms,respectively. Their amplitudes were(1.04±0.30)μV,(1.01±0.23)μV,(1.07±0.24)μV,(1.02±0.24)μV and (1.04±0.25)μV,respectively,and their amplitude densities were(68.78±19.84)nV/deg 2,(46.81±10.53)nV/deg 2,(34.27±7.86)nV/deg 2,(23.49±5.64)nV/deg 2 and (17.94±4.2)nV/deg 2,respectively. Statistical analysis showed that the amplitude densities of the a wave and b wave were greatest at the central fovea(the first ring). With an increase in eccentricity,the amplitude densities decreased and latencies increased. There were significant differences(P<0.01) between one ring and another,while no significant differences were found in the amplitude densities of the a wave or b wave in four retinal quadrants(P>0.05).Conclusion:m ERG can objectively measure and sensitively locate and quantify the visual function in different retinal regions and our results provide normal reference limits for clinical application.
出处
《眼视光学杂志》
2002年第2期72-74,共3页
Chinese Journal of Optometry & Ophthalmology
