Linear birefringence measurements of the in vitro human cornea

This paper presents results of an in vitro investigation of the optical anisotropy of the human cornea. Computer controlled imaging polarimetry and the Jones formalism were used to investigate the distribution of the birefringence and the azimuth angle across the surface of 12 corneas taken from the corneal bank. Each map of the birefringence and the azimuth angle has no rotational symmetry and is different for each cornea. The minimal value of the birefringence always appears in the corneal centre and varies from 9 to 43 degrees for different corneas. Birefringence of the cornea increases monotonically more than one order in the direction of the corneal periphery. Close to the centre of the cornea the azimuth angle is almost constant and varies significantly away from the optical part of the cornea.     

旋光法测定槐果碱注射液的含量

目的 采用旋光法测定槐果碱注射液的含量。方法 将样品稀释10倍，于20℃直接测定旋光度。结果 槐果碱的线性范围为4～40mg／mL（r=0．9999），平均回收率为100．45％，RSD=0．96％（n=5）。结论 方法快速、方便，适用于医院制剂的常规分析。     

旋光法快速测定倍他米松磷酸钠注射液的含量

目的 :建立倍他米松磷酸钠注射液的含量测定方法。方法 :以水为溶剂 ,采用旋光度测定法测定。结果 :倍他米松磷酸钠在 0 .5～ 10 mg/ ml浓度范围内与旋光度值呈良好线性关系 ,回归方程为 :C =10 .8814×α - 0 .0 979( r =0 .9995 ) ,平均回收率 :99.4 % ,RSD=1.0 1%。结论 :该方法简便 ,快速 ,准确。     

旋光法测定头孢氨苄胶囊中头孢氨苄含量

目的:建立快速测定头孢氨苄胶囊含量的方法。方法:以水为溶剂,采用旋光法测定头孢氨苄胶囊含量。结果:头孢氨苄在1.5~7.5 mg/ml范围内浓度与旋光度呈良好线性关系,回归方程C=-0.0012 0.6877X(r=1.0000),平均回收率100.2%,RSD为0.65%(n=9)。结论:本法简便易行,结果准确,可作为头孢氨苄胶囊的质控方法。     

旋光法测定培哚普利叔丁胺盐及培哚普利片含量

目的:建立培哚普利叔丁胺盐及培哚普利片含量测定方法。方法:以乙醇为溶剂,采用旋光法测定培哚普利叔丁胺盐及培哚普利片含量。结果:培哚普利叔丁胺盐在1.2~15 mg/ml范围内浓度与旋光度呈良好线性关系,回归方程C=0.005 4 1.468 8X,r=1.000 0,平均回收率99.6%,RSD为0.19%(n=9)。结论:本法简便易行,结果准确,可作为培哚普利叔丁胺盐及培哚普利片的质控方法。     

激动素对肝纤维化大鼠肝脏胶原变化的作用研究

目的:观察激动素(kinetin)对肝纤维化大鼠肝脏Ⅰ、Ⅲ型胶原含量的作用。方法:将实验大鼠随机分为3组,模型组用CCl4诱导形成肝纤维化模型;激动素组造模同时给予0.1%激动素溶液5ml·kg-1·d-1;对照组仅给予生理盐水皮下注射,均治疗12周。应用苦味酸天狼猩红偏振光法和图像分析技术对3组中的胶原含量及分布特点进行观察。结果:激动素组Ⅰ型胶原与Ⅲ型胶原含量分别为(2.107±0.833)%和(1.114±0.413)%,分别较模型组(4.473±2.311)%和(1.964±0.854)%显著降低(P<0.01)。结论:激动素能使肝纤维化大鼠肝脏Ⅰ、Ⅲ型胶原含量显著降低。     

Correlation between optic disc area and retinal nerve fiber layer thickness: a study on scanning laser polarimetry with variable corneal compensation

Purpose To evaluate if a significant increase of the peripapillary retinal nerve fiber layer (RNFL) thickness can be measured in a sample of healthy eyes by means of scanning laser polarimetry with variable corneal compensation (GDx-VCC) as the optic disc (OD) area increases. Methods One eye each of 232 healthy subjects (mean age: 57.8 years; range:40–70) was considered. Temporal-superior-nasal-inferior-temporal average (TSNIT Avg) and OD area (area within the ellipse placed on inner border of peripapillary scleral ring) values were collected. Ellipse horizontal and vertical diameters provided on printout were used to estimate OD area using the equation: OD area = π × horizontal radius×vertical radius. TSNIT Avg values were plotted against OD area and a multiple linear regression including age calculated. Results Mean OD area was 2.19 mm²±0.45 (range: 1.23–3.59) and mean TSNIT Avg was 54.3 μ ± 3.2 (range: 45.8–61.8). Multiple linear regression equation was TSNIT Avg=57.7−0.096×OD Area−0.055×Age (Pearson r=−0.146: p=0.086) Conclusion In our sample of healthy eyes, no significant correlation was found between TSNIT Avg and OD area. In spite of a shorter distance between OD and measurement ellipse margins, larger discs did not necessarily show a thicker RNFL. Probably the large inter-subject variability for RNFL thickness, and then for axonal count, was a predominant factor over OD area. None of the authors have any financial or proprietary interest with products cited in the text.     

Comparison of retinal nerve fiber layer measurements between NTG and HTG using GDx-vCC

PURPOSE: To compare quantitative polarimetric measurements in eyes with NTG and HTG using GDx-VCC. Both groups were matched by age and glaucoma stage based on the Humphrey visual field test. METHODS: We retrospectively reviewed the records of 146 patients who underwent Humphrey field analysis (HFA) and GDx-VCC. We compared outcomes of retinal nerve fiber layer (RNFL) parameters among the three groups by ANOVA and between each pair of groups using the Tukey-Kramer Post-Hoc test. We also evaluated the sensitivity and specificity of GDx-VCC in detecting glaucoma in each group. RESULTS: The mean age and HFA mean deviation (MD) were 55.6 +/- 9.5 years and -0.8 +/- 1.5 dB in 47 control patients, 59.4 +/- 9.0 years and -5.77 +/- 4.38 dB in 49 NTG patients, and 59.4 +/- 11.7 years and -8.09 +/- 6.77 dB in 51 HTG patients, respectively. All thickness parameters were lower in HTG patients compared to NTG patients, but there were no significant differences in ratio parameters between age-matched early HTG and NTG patients. The sensitivity of GDx-VCC was significantly higher in both early and total HTG patients compared to the respective groups of NTG patients. CONCLUSIONS: Compared to eyes with NTG, eyes with HTG showed reduced RNFL thickness and ratio parameters when patients were age and visual field matched. GDx-VCC appeared to be more sensitive in detecting RNFL damage in HTG patients.     

Assessment of rates of structural change in glaucoma using imaging technologies

Purpose

To review the ability of current imaging technologies to provide estimates of rates of structural change in glaucoma patients.

Patients and methods

Review of literature.

Results

Imaging technologies, such as confocal scanning laser ophthalmoscopy (CSLO), scanning laser polarimetry (SLP), and optical coherence tomography (OCT), provide quantifiable and reproducible measurements of the optic disc and parapapillary retinal nerve fibre layer (RNFL). Rates of change as quantified by the rim area (RA) (for CSLO) and RNFL thickness (for SLP and OCT) are related to glaucoma progression as detected by conventional methods (eg, visual fields and optic disc photography). Evidence shows that rates of RNFL and RA loss are significantly faster in progressing compared with non-progressing glaucoma patients.

Conclusion

Measurements of rates of optic disc and RNFL change are becoming increasingly precise and individualized. Currently available imaging technologies have the ability to detect and quantify progression in glaucoma, and their measurements may be suitable end points in glaucoma clinical trials.     

Stratus OCT与GDxVCC测量正常人与青光眼患者视网膜神经纤维层厚度比较研究

目的 比较相干光断层扫描仪StratusOCT与激光偏振光视网膜扫描仪GDxVCC测量视网膜神经纤维层(RNFL)厚度的相关性及差异,探讨两者测量值与视野的相关性及其对青光眼的诊断效能.方法 84例原发性开角型青光眼(POAG)患者及50名正常人,随机选取一眼进行StratusOCT和GDxVCCRNFL厚度测量及Humphery自动视野计检查.相关分析比较两种仪器测量的全周、上方、下方RNFL厚度;回归分析研究视野的平均偏差与两种仪器测量的RNFL厚度值之间的关系;ROC曲线下面积分析两种仪器诊断青光眼的效能.结果 Stratus OCT测量正常人及POAG患者的全周RNFL厚度分别为(100.00±7.36)μm和(75.12±17.11)μm,GDxVCC对应测量值(57.16±5.05)μm和(48.00.4±8.46)μm.两种仪器测量的RNFL厚度呈线性相关(r>0.75).两种仪器测量的RNFL厚度值与视野的平均偏差呈正相关,三次曲线拟合度较直线相关的拟合度好.对于青光眼诊断,Stratus OCT的最大ROC曲线下面积为0.908,GDxVCC最大ROC曲线下面积为0.842.结论 Stratus OCT与GDxVCC测量RNFL厚度值存在差异,但两者呈线性相关,均与视野的平均偏差呈曲线相关.两种仪器诊断青光眼的效能均较好.