年龄对正常成年人视网膜神经纤维层厚度的影响

 目的 使用偏振激光扫描仪对部分健康的中国成年人视网膜神经纤维层（RNFL）厚度进行测定,评估年龄和RNFL厚度之间的关系。方法 使用GDxVCC神经纤维分析仪的两种不同检测模式（可变角膜补偿,VCC;强化角膜补偿,ECC）测定150例患者共150眼的视网膜神经纤维层厚度。测量参数包括：颞侧-上方-鼻侧-下方-颞侧平均（TSNITave）、上方平均（Superiorave）、下方平均（Inferiorave）、TSNIT标准差（TSNITstdDev）。和神经纤维指数（NFI）。结果 VCC检测模式得到的TSNITave、Superiorave、Inferiorave、TSNITstdDev、NFl平均值分别为（57.12±6.26）,（69.35±4.21）,（67.59±7.06）,（25.46±4.02）,（17.35±7.59）。ECC检测模式五项检测值分别为：（56.15±5.32）,（68.24±6.63）,（66.90±2.40）,（24.80±6.76）,（18.84±8.51）。VCC和ECC模式的检测值之间的差异不具统计学意义。在总样本人群中检测参数指标与年龄存在统计学意义的相关性。而在40岁以上人群中检测参数指标与年龄未发现相关性。结论 VCC和ECC模式对检测150例正常国人视网膜神经纤维层厚度的检测值之间不存在统计学差异。对21～70岁的健康人眼中,RNFL厚度检测值随年龄增长而变薄,但在40岁以上人群中未见此改变。     

无糖尿病视网膜病变表现的糖尿病患者视网膜神经纤维层厚度的研究

目的 研究糖尿病患者是否存在视网膜神经纤维层(retinal nerve fiber layer,RNFL)的变薄,并分析RNFL厚度和若干糖尿病危险因素之间的相关性.方法 42位2型糖尿病患者(47～70岁)被纳入该研究.所有患者接受常规眼科检查和GDxVCC神经纤维分析仪检查(包括可变角膜补偿模式VCC和强化角膜补偿模式ECC).GDx测量参数包括:颞侧-上方-下方-鼻侧-颞侧平均(TSNITave),上方平均(Superiorave),下方平均(Inferiorave),TSNIT标准差(TSNITstdDev)和神经纤维指数(NFI).通过计算受试者工作曲线(ROC)分析各指标的诊断能力,并研究相关危险因素与NFI值之间的关系.结果 在ECC和VCC检测模式下,NFI值的ROC曲线下面积均是最大的.年龄增长和视网膜神经纤维层变薄之间存在统计学意义的相关性.然而,在糖尿病病程和空腹血糖与RNFL 厚度之间未发现具统计学意义的相关性.年龄对糖尿病患者的NFI检测值的影响大于对正常对照人群NFI值的影响.结论 年龄因素对糖尿病患者的NFI值具有重要影响.眼底尚表现正常的糖尿病患者可能已存在视网膜神经纤维层变薄.     

GDx神经纤维厚度分析仪在正常中老年国人中的应用评价

目的 评价GDx神经纤维厚度分析仪在正常中老年国人中的检测意义。方法 采用GDx神经纤维厚度分析仪两种检测模式检测正常中老年国人的视网膜神经纤维层（RNFL）厚度。测量参数：TSNIT平均延迟、上方平均延迟、下方平均延迟、TSNIT标准差、神经纤维指数（NFI）。结果 VCC模式：5项参数分别为56.17±5.25,68.35±7.20,67.31±8.06,23.46±4.31,17.15±10.09。ECC模式：5项参数分别为54.15±5.12,67.28±8.33,67.91±8.70,25.80±3.72,18.88±10.51。两种模式参数检测结果均在正常范围,除下方平均延迟差异有统计学意义外其余4项参数之间的差异无统计学意义,所有检测参数指标与年龄均无统计学意义的相关性。结论 GDx神经纤维厚度分析仪对正常中老年国人RNFL厚度分布的测定结果符合生理解剖特点。VCC和ECC两种模式对检测正常中老年国人的RNFL厚度差异无统计学意义。     

Clinical evaluation of scanning laser polarimetry: II Polar profile shape analysis

AIMS—To devise a method to describe and quantify the shape of polar profiles obtained with the scanning laser polarimeter and to compare this measurement with other polar profile measurements in a series of normal subjects and glaucoma patients.
METHODS—Scanning laser polarimetry was performed on 54 normal subjects and 74 glaucoma patients. The retardation values obtained from one randomly chosen eye of each subject were analysed using our own methods, including the use of an algorithm to remove blood vessels from the polar profiles, an algorithm to standardise the glaucoma profiles to a normal database, and a further algorithm to evaluate the profile shape. The measurements of profile shape were compared with measurements of the absolute and standardised retinal nerve fibre layer thickness obtained with the scanning laser polarimeter.
RESULTS—There was no significant difference between the mean retardation values for the normal and glaucomatous subjects in either hemiretina. However, standardisation of the glaucoma retardation values to a normal database produced significant differences at p <1 × 10⁻⁸ in the mean retardation values for these two groups in both hemiretinas. Profile shape measurement analysis produced similar significant differences between the mean retardation values for the normal and glaucomatous subjects in both hemiretinas, although the degree of separation was greater following standardisation of the retardation values.
CONCLUSION—The use of an algorithm to standardise an individual's retardation values in conjunction with a blood vessel removal algorithm enables an improvement in the ability of the scanning laser polarimeter to discriminate between normal and glaucomatous patients. The polar profile shape algorithm is independent of standardisation and significantly improves the discrimination between normal and glaucomatous patients, as well as providing additional information regarding the retinal nerve fibre layer.

Keywords: scanning laser polarimetry; glaucoma; profile shape analysis     

Rates of retinal nerve fibre layer thickness change in glaucoma patients and control subjects

Purpose

To examine the rates of retinal nerve fibre layer thickness (RNFLT) change in glaucoma patients and healthy, age-similar control subjects with three techniques: scanning laser polarimetry with variable corneal compensation (VCC) and enhanced corneal compensation (ECC), and time-domain optical coherence tomography (OCT).

Methods

Sixty-one patients and thirty-three controls were examined with each technique and with standard automated perimetry (SAP) every 6 months. Rates of global RNFLT change and SAP mean deviation (MD) change were estimated with linear mixed-effects models.

Results

The median (interquartile range) baseline age was 64.4 (58.2, 71.0) years for patients and 62.4 (56.3, 70.1) years for controls (P=0.56). There was a median of seven examinations over 3.1 years for patients and six examinations in 3.0 years for controls. Baseline visual field MD and RNFLT for all imaging modalities were significantly lower (P<0.01) in patients compared with controls. Rates of RNFLT change were not significantly different between patients and controls (P≥0.19). Mean rates of VCC-measured RNFLT change were −0.18 and −0.37 μm per year in patients and controls, whereas the respective figures for ECC and OCT were −0.13 and −0.31 μm per year, and 0.04 and 0.61 μm per year. Mean rates of MD change were −0.20 and 0.03 dB per year in patients and controls, respectively (P=0.01).

Conclusion

Rates of RNFLT change in glaucoma patients were not statistically different from control subjects for any modality. A significantly negative rate of MD change in patients suggests a genuine, continued deterioration in these patients not reflected by RNFLT changes.     

Glaucoma progression detection by retinal nerve fiber layer measurement using scanning laser polarimetry: event and trend analysis

Purpose

To evaluate the use of scanning laser polarimetry (SLP, GDx VCC) to measure the retinal nerve fiber layer (RNFL) thickness in order to evaluate the progression of glaucoma.

Methods

Test-retest measurement variability was determined in 47 glaucomatous eyes. One eye each from 152 glaucomatous patients with at least 4 years of follow-up was enrolled. Visual field (VF) loss progression was determined by both event analysis (EA, Humphrey guided progression analysis) and trend analysis (TA, linear regression analysis of the visual field index). SLP progression was defined as a reduction of RNFL exceeding the predetermined repeatability coefficient in three consecutive exams, as compared to the baseline measure (EA). The slope of RNFL thickness change over time was determined by linear regression analysis (TA).

Results

Twenty-two eyes (14.5%) progressed according to the VF EA, 16 (10.5%) by VF TA, 37 (24.3%) by SLP EA and 19 (12.5%) by SLP TA. Agreement between VF and SLP progression was poor in both EA and TA (VF EA vs. SLP EA, k = 0.110; VF TA vs. SLP TA, k = 0.129). The mean (±standard deviation) progression rate of RNFL thickness as measured by SLP TA did not significantly differ between VF EA progressors and non-progressors (-0.224 ± 0.148 µm/yr vs. -0.218 ± 0.151 µm/yr, p = 0.874). SLP TA and EA showed similar levels of sensitivity when VF progression was considered as the reference standard.

Conclusions

RNFL thickness as measurement by SLP was shown to be capable of detecting glaucoma progression. Both EA and TA of SLP showed poor agreement with VF outcomes in detecting glaucoma progression.     

The retinal nerve fibre layer thickness in glaucomatous hydrophthalmic eyes assessed by scanning laser polarimetry with variable corneal compensation in comparison with age‐matched healthy children

Purpose: To compare the thickness of the retinal nerve fibre layer (RNFL) in hydrophthalmic glaucomatous eyes in children with age‐matched healthy controls using scanning laser polarimetry with variable corneal compensation (GDxVCC). Methods: Twenty hydrophthalmic eyes of 20 patients with the mean age of 10.64 ± 3.02 years being treated for congenital or infantile glaucoma were included in the analysis. Evaluation of RNFL thickness measured by GDxVCC in standard Temporal‐Superior‐Nasal‐Inferior‐Temporal (TSNIT) parameters was performed. The results were compared to TSNIT values of an age‐matched control group of 120 healthy children published recently as referential values. The correlation between horizontal corneal diameter and RNFL thickness in hydrophthalmic eyes was also investigated. Results: The mean ± SD values in TSNIT Average, Superior Average, Inferior Average and TSNIT SD in hydrophthalmic eyes were 52.3 ± 11.4, 59.7 ± 17.1, 62.0 ± 15.6 and 20.0 ± 7.8 μm, respectively. All these values were significantly lower compared to referential TSNIT parameters of age‐matched healthy eyes (p = 0.021, p = 0.001, p = 0.003 and p = 0.018, respectively). A substantial number of hydrophthalmic eyes laid below the level of 5% probability of normality in respective TSNIT parameters: 30% of the eyes in TSNIT average, 50% of the eyes in superior average, 30% of the eyes in inferior average and 45% of the eyes in TSNIT SD. No significant correlation between enlarged corneal diameter and RNFL thickness was found. Conclusions: The mean values of all standard TSNIT parameters assessed using GDxVCC in hydrophthalmic glaucomatous eyes in children were significantly lower in comparison with referential values of healthy age‐matched children.     

Retinal nerve fiber layer in primary open-angle glaucoma with high myopia determined by optical coherence tomography and scanning laser polarimetry with variable corneal compensation

Background Fundus changes associated with high myopia (HM) may mask those associated with primary open-angle glaucoma (POAG). Characteristic retinal nerve fiber layer (RNFL) thickness profiles in patients with POAG and HM were examined using optical coherence tomography (OCT) and scanning laser polarimetry with variable corneal compensation (GDxVCC), and the diagnostic capabilities of these imaging modalities were compared. Methods Twenty-two eyes with POAG and HM (spherical equivalent [SE] between -6.0 and -12.0 D) were evaluated, and 22 eyes with HM were used for comparison. RNFL parameters evaluated included superior average (Savg-GDx), inferior average (Iavg-GDx), temporal-superior-nasal- inferior-temporal (TSNIT) average, and nerve fiber indicator (NFI) on GDxVCC and superior average (Savg-OCT), inferior average (Iavg-OCT), nasal average (Navg-OCT), temporal average (Tavg-OCT), and average thickness (AvgThick-OCT) on OCT (fast RNFL scan). Visual field testing was performed and defects were evaluated using mean defect (MD) and pattern standard deviation (PSD). Results The RNFL parameters (P < 0.05) that were significantly different between groups included Savg-GDx, Iavg-GDx, TSNIT average, NFI, Savg-OCT, Iavg-OCT, Tavg-OCT, and AvgThick-OCT. Significant correlations existed between TSNIT average and AvgThick-OCT (r = 0.778), TSNIT average and MD (r = 0.749), AvgThick-OCT and MD (r = 0.647), TSNIT average and PSD (r = -0.756), and AvgThick-OCT and PSD (r = -0.784). The area under the receiver operating characteristic curve (AUROC) values of TSNIT average, Savg-GDx, Iavg-GDx, NFI, Savg-OCT, Iavg-OCT, Navg-OCT, Tavg-OCT, and AvgThick-OCT were 0.947, 0.962, 0.973, 0.994, 0.909, 0.917, 0.511, 0.906, and 0.913, respectively. The NFI AUROC was the highest value. Conclusion RNFL thickness was significantly lower in all but the nasal quadrant in patients with POAG and HM, compared to patients with only HM. Measurements with OCT and GDxVCC were well-correlated, and both modalities detected RNFL thickness changes. However, GDxVCC was better than OCT in detecting POAG in HM patients.     

Scanning laser polarimetry in glaucoma

Glaucoma is an acquired progressive optic neuropathy which is characterized by changes in the optic nerve head and retinal nerve fiber layer (RNFL). White-on-white perimetry is the gold standard for the diagnosis of glaucoma. However, it can detect defects in the visual field only after the loss of as many as 40% of the ganglion cells. Hence, the measurement of RNFL thickness has come up. Optical coherence tomography and scanning laser polarimetry (SLP) are the techniques that utilize the evaluation of RNFL for the evaluation of glaucoma. SLP provides RNFL thickness measurements based upon the birefringence of the retinal ganglion cell axons. We have reviewed the published literature on the use of SLP in glaucoma. This review elucidates the technological principles, recent developments and the role of SLP in the diagnosis and monitoring of glaucomatous optic neuropathy, in the light of scientific evidence so far.