屈光间质混浊对Humphrey视野计及倍频视野计检查结果的影响(英文)

目的:用弥散滤片模拟瞳孔及屈光间质的变化,以比较这些变化对Humphrey视野计(HFA)及倍频视野计(FDT)的影响。方法:测试15位23-39岁正常人的左眼: (1) Snellen视力表; (2) Pelli-Robson(P-R)对比敏感度视力表; (3)白视标白背景自动视野计检查,HFA Model630,采用30-2程序,刺激视标为III; (4) FDT检查,采用N-30程序。每一只眼均经无滤片,1, 2, 3, 4, 5个滤片进行测试,测试顺序为随机。结果:Snellen视力表: 1个滤片只对2名受试者有影响,仅丢失1行; 2个滤片对所有受试者影响甚微,对2名受试者无影响(9名丢失1行,4名丢失2行); 3个滤片对所有受试者效果一样,均丢失3行; 4个滤片可致5名受试者丢失4行,5名受试者丢失5行, 3名受试者丢失6行, 2名受试者丢失7行;5个滤片可致所有受试者丢失全部9行。P-R视力表:3个滤片便可致13名受试者看不到所有字母,2名受试者仅看到1组字母。HFA和FDT的平均偏差值(MD)均随滤片增加而降低,HFA和FDT的图形标准差值(PSD)较小且非常一致。结论:以上结果表明,由弥散滤片所致的照明降低,光散射及瞳孔缩小对HFA及FDT均有明显影响,其视野缺损比较弥散均匀,而屈光间质混浊对FDT的影响比对HFA的影响要大。各组滤片的PSD值比较小且非常一致。

Effect of optical media changes on white-on-white Humphry field analyser perimetry and frequency doubling technology perimetry

AIM: To simulate the effect of changes of pupil size and optical media with diffusing filters on visual acuity, and to compare these effects on Humphrey field analyser(HFA) and frequency doubling technology (FDT) perimetry. METHODS: The left eyes of 15 normal subjects aged 23-39 years underwent: 1) Snellen visual acuity and Pelli-Robson(P-R) chart testing; 2) white-on-white automatic perimetry of HFA model 630 using the 30-2 programme and size III stimulus; 3) FDT perimetry using N-30 programme. For each procedure, no filter, 1, 2, 3, 4 and 5 diffusing filters were mounted in random order in front of the eye to be tested.RESULTS: For Snellen visual acuity, 1 filter had no effect on all but 2 subjects who lost 1 line; 2 filters had little effect on all subjects and had no effect on 2 subjects (9 subjects lost 1 line and 4 lost 2 lines); 3 filters had the same effect on all subjects who lost 3 lines; 4 filters caused 5 subjects to lose 4 lines, 5 subjects to lose 5 lines, 3 subjects to lose 6 lines and 2 subjects to lose 7 lines; 5 filters caused 9 lines loss in all the subjects. For P-R chart , 3 filters usage caused 13 subjects to see none of the groups of letters and while 2 subjects could see only 1 group of letters. Both mean deviation(MD) of HFA and FDT were reduced with increased numbers of filters. For HFA, 5 filters caused nearly absolute scotomas, while for FDT, 3 filters caused the same result. The pattern standard deviation(PSD) for both HFA and FDT was uniformly consistent; the short-term fluctuation(SF) and corrected pattern standard deviation(CPSD) were all uniformly consistent.CONCLUSION: These findings showed that luminance reduction and light scattering caused by diffusing filters have marked effect on white-on-white and frequency doubling perimetry; the visual field loss of HFA and FDT was relatively diffuse, which could be effectively reduced through the use of pattern deviation analysis in separating visual field loss caused by glaucoma from that caused by cataract; the effect of media opacities on FDT was greater than it on HFA.