应用GDx VCC检测原发性开角型青光眼视网膜神经纤维层

目的 采用GDx VCC检测青光眼和正常人视网膜神经纤维层厚度(retinal nerve fiber layer,RNFL),并进行对比分析.方法 选择正常人44人44眼,原发性开角型青光眼患者45例45眼行GDx VCC检查.将获取的参数(椭圆平均值、上方平均值、下方平均值、TSNIT标准差、眼间对称性、视神经纤维指征)进行分析.结果 所有参数在正常人组与青光眼组比较中均有统计学意义(P＜0.01).GDxVCC不同参数检测青光眼RNFL缺损敏感性为68.9%～82.2%,特异性84.1%～100.0%.其中下方平均值、视神经纤维指征ROC曲线下面积为0.959、0.964.结论 GDx VCC在RNFL检查中有较高的敏感性和特异性,可客观反应受检者的RNFL情况,对于青光眼的早期诊断有一定的临床价值.     

Long-term variability of GDx VCC retinal nerve fiber layer thickness measurements

PURPOSE: To evaluate the long-term variability of GDx VCC retinal nerve fiber layer (RNFL) thickness measurements. METHODS: The study enrolled a cohort of glaucoma suspects who did not develop any evidence of visual field damage or change in the appearance of the optic nerve during an average follow-up of 9.1+/-3.2 years. Subjects underwent ocular imaging using the commercially available GDx VCC scanning laser polarimeter. At each visit, each eye was imaged 3 times. Subjects underwent repeated testing with GDx VCC at approximately 12-month intervals during their follow-up. In total, 255 examinations were obtained in 31 eyes of 31 individuals during an average GDx VCC follow-up time of 26.0+/-8.9 months. A random effects analysis of variance model was used to estimate intraclass correlation coefficients and long-term and short-term variability estimates. RESULTS: Intraclass correlation coefficients ranged from 0.77 to 0.86 for GDx VCC parameters. Short-term variability estimates ranged from 2.45 to 3.89 microm for RNFL thickness parameters, whereas the short-term variability estimate for the parameter Nerve Fiber Indicator was 3.71. Long-term variability was slightly higher than short-term variability for all parameters. For RNFL thickness parameters, long-term variability estimates ranged from 3.21 to 4.97 microm, whereas for the parameter Nerve Fiber Indicator the long-term variability estimate was 4.93. CONCLUSIONS: RNFL measurements obtained with the GDx VCC were found to be highly reproducible in a long-term test-retest situation, supporting the use of this instrument for longitudinal assessment of the RNFL.     

Preperimetric glaucoma assessment with scanning laser polarimetry (GDx VCC): analysis of retinal nerve fiber layer by sectors

PURPOSE: To evaluate the capability of the GDx VCC nerve fiber analyzer to detect preperimetric glaucoma across 12 retinal nerve fiber layer (RNFL) peripapillary sectors. METHODS: Data were obtained in a cross-sectional, hospital clinic-based study; 699 eyes from 699 glaucoma suspects were enrolled in this protocol. All subjects underwent ophthalmologic examination, static automated perimetry [Humphrey 24-2 Swedish interactive threshold algorithm (SITA) Standard], optic nerve stereoscopic photographs, red-free digital RNFL photographs and GDx VCC examination. Group S included 283 normal eyes and 39 preperimetric glaucoma eyes with RNFL superior or diffuse defects in the fiber layer photographs. Group I included 324 normal subjects and 24 with preperimetric glaucoma eyes with RNFL inferior or diffuse defects in fiber layer photographs. RESULTS: Mean values of the area under the curve (AUC) for receiver operating characteristic analysis for inferior average (Inf Avg), temporal-superior-nasal-inferior temporal average (TSNIT Avg), superior average (Sup Avg), and the nerve fiber indicator were significantly less in the eyes with RNFL defects than the control group compared with the AUC for thickness at hour 12 and at hour 6 calculated from the RNFL sector density. The AUC for receiver operating characteristic analysis of the new parameters improved by 12% with respect to the best GDx VCC standard values. CONCLUSIONS: Our results confirm that the 12 sector divisions of the GDx VCC have better diagnostic reliability in preperimetric glaucoma, and are able to improve the discrimination capability between normal and early damaged RNFLs.     

Comparative study of retinal nerve fiber layer loss in normal-tension glaucoma and chronic open-angle glaucoma

PURPOSE: To clarify whether loss of the retinal nerve fiber layer in normal-tension glaucoma (NTG) differs from that in chronic open-angle glaucoma (COAG). METHODS: Using a scanning laser polarimeter, retinal nerve fiber layer thickness (RNFLT) was measured in 21 patients with NTG, 21 patients with COAG and 21 normal controls. The three groups were matched for age, and the NTG and COAG groups were matched for visual field loss. RESULTS: The mean RNFLT was significantly less in the NTG than in the control group and less in the COAG than in the controls and NTG group. Although the correlations between the parameters of RNFLT and homotopic visual field measurements were significant in COAG, none of the correlations were significant in NTG. CONCLUSIONS: The present results suggest that loss of the retinal nerve fiber layer in NTG differs from that in COAG.     

Polarimetric measurement of retinal nerve fiber layer thickness in glaucoma diagnosis

PURPOSE: To evaluate reliability and diagnostic value of polarimetric measurements of the retinal nerve fiber layer (RNFL) thickness in the diagnosis of glaucoma. METHODS: The study included 81 eyes with perimetric glaucoma with glaucomatous changes of the optic disc and visual field defects; 52 eyes with preperimetric glaucoma with glaucomatous optic disc abnormalities and normal achromatic visual fields; and 70 normal eyes. For determination of reliability, four examiners repeated polarimetric measurements five times in ten normal subjects. RESULTS: The polarimetric variables were significantly correlated with increasing mean visual field defect and decreasing neuroretinal rim area. In correlation analyses with visual field defects, correlation coefficients were highest for the variable "superior/nasal ratio" and "the Number," a variable calculated by the neural network of the device. In correlations with neuroretinal rim area, correlation coefficients were highest for measurements of the inferior nerve fiber layer thickness. The preperimetric glaucoma group and the control group differed significantly in the variables "superior/nasal ratio" and "the Number" and, to a smaller degree, in the variables "superior/temporal ratio" and "superior/inferior ratio." The Number variable had a sensitivity of 82% and 58% at a predefined specificity of 80% in separating perimetric glaucoma patients and preperimetric glaucoma patients, respectively, from control subjects. Reproducibility of the polarimetric measurements ranged between 70% and 89%. CONCLUSION: Polarimetric measurements of the RNFL thickness can detect glaucomatous optic nerve damage in patients with visual field loss, and in some patients with preperimetric glaucomatous optic nerve damage. Considering the fast performance, easy handling, and low maintenance costs, RNFL polarimetry may be helpful in glaucoma diagnosis.     

Assessment of peripapillary retinal nerve fiber layer thickness using scanning laser polarimetry (GDx VCC) in normal Indian children

Purpose:

To obtain reference values of RNFL thickness in normal Indian children and to study the association of RNFL thickness with central corneal thickness(CCT) and axial length(AL).

Materials and Methods:

200 normal Indian children (mean age 8.6 ± 2.9 yrs) were examined on the GDxVCC. The inferior average (IA), superior average (SA), temporal-superior-nasal-inferior-temporal (TSNIT) average and nerve fiber index (NFI) values were recorded and compared between males and females as well as between the different age groups. The association of TSNIT average with AL and CCT was examined.

Results:

Values for the RNFL parameters were-SA: 64.9 ± 9.7, IA: 63.8 ± 8.8, TSNIT average: 53.5 ± 7.7 and NFI 21.5 ± 10.8. Superior, inferior and TSNIT averages did not differ significantly between males and females (P = 0.25, P = 0.19, P = 0.06 respectively; Mann-Whitney U test). No significant differences were found in TSNIT average across age groups. There was a statistically significant positive correlation between CCT and TSNIT average (r = 0.25, r² = 0.06, P < 0.001). The correlation TSNIT average and AL(r = −0.12; r² = 0.01) was not significant (P = 0.2).

Conclusion:

Reference values for RNFL parameters reported for Indian children are similar those reported in adults. There is a small correlation between central corneal thickness and RNFL as reflected in average TSNIT.     

Optic nerve and retinal nerve fiber layer analyzers in glaucoma

There is mounting evidence that retinal nerve fiber layer (RNFL) loss precedes detectable visual field loss in early glaucomatous optic neuropathy. However, examination and photography of the RNFL is a difficult technique in many patients, particularly older individuals, and eyes with small pupils and media opacities. It is subjective, qualitative, variably reproducible, and often unreliable. Furthermore, optic nerve head and RNFL photography is time consuming, operator dependent, has limited sensitivity and specificity, and requires storage space. Imaging technologies have emerged which enable clinicians to perform accurate, objective, and quantitative measurements of the RNFL and optic nerve head topography. There is good agreement between such measurements and clinical estimates of optic nerve head structure and visual function. The reproducibility of these instruments suggests that they have the potential to detect structural change over time. This report will review the technological principles, reproducibility, sensitivity and specificity, capacity to detect glaucomatous progression, and limitations of currently available ocular imaging technologies.     

Comparative study of retinal nerve fiber layer damage in Japanese patients with normal- and high-tension glaucoma

PURPOSE: To look for possible differences in the pattern of retinal nerve fiber layer (RNFL) damage induced by normal- and high-tension glaucoma. METHODS: The study included randomly selected eyes from 27 patients with open-angle, high-tension glaucoma (mean age, 54.7 +/- 15.0 years; range 21-74 years) and from 19 age-matched patients with normal-tension glaucoma (mean age, 55.7 +/- 11.9 years; range 35-83 years). Eyes were examined using scanning laser polarimetry. RESULTS: The ratio between the superior and inferior quadrant thickness, or symmetry, was significantly lower in patients with high-tension glaucoma (1.00 +/- 0.22) than in patients with normal-tension glaucoma (1.18 +/- 0.32). Similarly, the ratio of the superior to the nasal quadrant thickness was significantly lower in patients with high-tension glaucoma (1.56 +/- 0.38) than in patients with normal-tension glaucoma (1.80 +/- 0.29). No statistically significant differences in the other parameters were detected between the two groups. CONCLUSION: These results show that the pattern of RNFL change is different in patients with high- and low-tension glaucoma. The thickness of the RNFL is reduced symmetrically in the superior and inferior quadrants in high-tension glaucoma, whereas a more localized defect on the inferior RNFL occurs in normal-tension glaucoma.     

Effect of change in macular birefringence imaging protocol on retinal nerve fiber layer thickness parameters using GDx VCC in eyes with macular lesions

This study evaluates the effect of two macular birefringence protocols (bow-tie retardation and irregular macular scan) using GDx VCC on the retinal nerve fiber layer (RNFL) thickness parameters in normal eyes and eyes with macular lesions. In eyes with macular lesions, the standard protocol led to significant overestimation of RNFL thickness which was normalized using the irregular macular pattern protocol. In eyes with normal macula, absolute RNFL thickness values were higher in irregular macular pattern protocols with the difference being statistically significant for all parameters except for inferior average thickness. This has implications for monitoring glaucoma patients who develop macular lesions during the course of their follow-up.     

Accuracy of GDx VCC, HRT I, and clinical assessment of stereoscopic optic nerve head photographs for diagnosing glaucoma

AIMS: To determine and compare the accuracy and reproducibility of GDx variable cornea compensation (VCC) scanning laser polarimetry (SLP) with VCC, Heidelberg retina tomograph (HRT) I confocal scanning laser ophthalmoscopy (CSLO), and clinical assessment of stereoscopic optic nerve head (ONH) photographs for diagnosing glaucoma. METHODS: One eye each of 40 healthy subjects, 48 glaucoma patients, and six patients with ocular hypertension were measured with SLP-VCC and CSLO. Simultaneous stereoscopic ONH photographs were also obtained. Sixteen photographs of healthy and glaucomatous eyes were duplicated for assessing intraobserver agreement. Four glaucoma specialists, four general ophthalmologists, four residents in ophthalmology, and four optometrists classified the ONH photographs as normal or glaucomatous. For SLP-VCC, the nerve fiber indicator (NFI) was evaluated. For CSLO, the Moorfields regression analysis (MRA) and the Bathija linear discriminant function (LDF) were used. Sensitivity, specificity, percentage of correctly classified eyes, and intra- and interobserver agreement, expressed as kappa (kappa) were calculated. RESULTS: SLP-VCC had the highest diagnostic accuracy, with a sensitivity, specificity, and overall correct classification of 91.7%, 95.0% and 93.2%, respectively. CSLO, expressed as Bathija LDF and MRA, had a diagnostic accuracy comparable to glaucoma specialists and general ophthalmologists with an overall accuracy of 89.8%, 86.4%, 86.7% and 85.2%, respectively. Residents classified the fewest eyes correctly. Intraobserver agreement for classifying the ONH photographs ranged between 0.48 (within residents) and 0.78 (within glaucoma specialists). The interobserver agreement ranged between 0.45 (between residents) and 0.74 (between glaucoma specialists). The agreement between observers and CSLO MRA (kappa, 0.68) was statistically significantly higher (p<0.001; paired t-test) than between observers and SLP-VCC NFI (kappa, 0.60) and CSLO Bathija LDF (kappa, 0.62). CONCLUSION: Automated analysis of measurements with GDx VCC and HRT had a similar diagnostic accuracy for glaucoma as classification of stereoscopic ONH photographs by glaucoma specialists, thus bringing all eye-care professionals to this desirable level. The intra- and interobserver agreement for ONH analysis was only moderate to good. We think these imaging techniques may assist clinicians in diagnosing glaucoma.     

Preservation of nerve fiber layer by retinal vessels in glaucoma.

The authors evaluated the correlation between various parameters and the local preservation of the retinal nerve fiber layer in 156 glaucomatous eyes. A vessel-associated preservation of the nerve fiber layer was observed in 45 of the 156 glaucomatous eyes. The presence of "straight" retinal vessels (either arterioles or large venules) and "tortuous" retinal vessels (large or small venules) inside of the scleral ring was correlated with the local preservation of the nerve fiber layer (P less than 0.001 and P less than 0.05, respectively). A local elevation of the floor of the cup was also correlated with the preservation of the nerve fiber layer (P less than 0.01). However, no correlation existed between either the preservation of the nerve fiber layer and the type of glaucoma, sex or age of patient, tilting of the disc, cilioretinal vessel, vertical cup-to-disc ratio, refractive error, disc size, distance between the disc and foveola, or the index of ovalness of the disc. These results suggest that retinal vessels in the disc significantly influence the vulnerability of the nerve fibers to glaucomatous damage.     

Evaluation of the retinal nerve fiber layer in glaucoma

The health of the optic nerve in glaucoma can be evaluated by examination of the retinal nerve fiber layer with red free illumination. Retinal nerve fiber layer defects have been shown in some studies to precede enlargement of optic cupping and visual field defects in glaucoma patients. Detection of glaucomatous damage at an earlier stage in the disease may prevent subsequent visual field loss. Retinal nerve fiber layer evaluation may give important information in the management and treatment of glaucoma patients.     

Impact of diabetic retinopathy on quantitative retinal nerve fiber layer measurement and glaucoma screening

PURPOSE: To investigate the impact of diabetic retinopathy on quantitative retinal nerve fiber layer (RNFL) assessment and diagnostic power for glaucoma by scanning laser polarimetry (GDx-VCC) and optical coherence tomography (StratusOCT). METHODS: The individual RNFL parameters of GDx and OCT were obtained for 170 eyes (one eye from each of 170 subjects [45 healthy, 47 glaucoma, 40 diabetes, and 38 glaucoma with diabetes]) and were compared among the four groups. Diabetic eyes had mild to moderate nonproliferative diabetic retinopathy (NPDR) without maculopathy. In glaucomatous eyes with or without diabetes, the ability to discriminate glaucoma was assessed by the areas under the receiver operating characteristic curves (AUROCs) and the sensitivities at more than 80% and 90% of specificities for each technique. RESULTS: Using GDx-VCC, significant differences (P < 0.05) in RNFL measurement parameters were found for all comparisons except those between glaucomatous eyes with diabetes and without diabetes. StratusOCT parameters did not detect significant differences between age-matched healthy and diabetic eyes. Among the parameters included, the nerve fiber indicator (NFI) of GDx-VCC and the inferior quadrant thickness (IQT) of StratusOCT had the largest AUROCs and sensitivities at specificities greater than 80%: NFI (0.912, 86%) and IQT (0.902, 85%) in glaucomatous eyes with diabetes; NFI (0.935, 92%) and IQT (0.921, 91%) in simple glaucomatous eyes. CONCLUSIONS: Mild to moderate NPDR causes a quantitative discrepancy in RNFL measurements between GDx-VCC and StratusOCT in simple diabetic eyes. However, mild to moderate glaucomatous optic neuropathy can be highly discriminated by the two imaging devices in eyes with diabetic retinopathy.     

Color vision and retinal nerve fiber layer in early glaucoma

We tested 47 eyes in 47 patients (ten normal subjects, 15 with suspected glaucoma, and 22 with glaucoma) with the Pickford-Nicholson anomaloscope to assess the retinal nerve fiber layer and measure color vision. The 47 subjects were randomly selected from a group of 132 for whom Farnsworth-Munsell 100-hue color error scores were known. The yellow-blue and green-blue anomaloscopic matching ranges correlated significantly with diffuse retinal nerve fiber loss. There was no correlation with localized retinal nerve fiber loss.     

Measurement of peripapillary retinal nerve fiber layer volume in glaucoma

PURPOSE: To measure peripapillary retinal nerve fiber layer volume in normal subjects and patients with ocular hypertension, primary open-angle glaucoma, and low-tension glaucoma. METHODS: Sixty-five subjects were classified into four groups of normal subjects and subjects with ocular hypertension, primary open-angle glaucoma, and low-tension glaucoma on the basis of intraocular pressure measurements, visual field loss, and optic disk appearance. Groups were matched for sex, age, and optic disk area. Peripapillary retinal nerve fiber layer volume measurements were made with a modification of software version 1.11 of the Heidelberg Retina Tomograph confocal scanning laser ophthalmoscope. Retinal nerve fiber layer volume measurements were taken at 0.1-mm increments from the disk margin for a global 360-degree assessment and at four predefined segments using two different reference planes. Statistical analysis was carried out using analysis of variance with Bonferroni correction. RESULTS: Retinal nerve fiber layer volume measurements showed a gradation from normal to ocular hypertension and from ocular hypertension to glaucoma groups. Mean group measurements showed statistically significant differences (P <.05) in peripapillary retinal nerve fiber layer volume for most segmental measures between the groups. Measurements with the default reference plane in the 0.0-mm to 0.1-mm and 0.1-mm to 0.2-mm increments for the superotemporal segment showed the greatest differences between groups (P <.00005). CONCLUSION: Peripapillary retinal nerve fiber layer volume measurements differ between groups of normal subjects and patients with ocular hypertension, primary open-angle glaucoma, and low-tension glaucoma. This measure offers a further method of assessment of retinal nerve fiber layer in patients with glaucoma and glaucoma suspects.     

Multiple defects in the retinal nerve fiber layer in glaucoma

We investigated the parameters that correlated with multiple defects in the retinal nerve fiber layer in 77 human eyes with normal-tension glaucoma, 110 with chronic high-tension glaucoma, and 102 control eyes. All 187 glaucomatous eyes had a nerve defect that was multiple in 20 cases. Correlation was significant between the multiple defect and the type of defect in the nerve fiber layer (P < 0.002), size of the disc (P < 0.02), and oblique insertion of the disc (P < 0.02), as evaluated by the chisquare test. By multivariate analysis, refractive error was a high-ranking risk factor for multiple defect. Eyes with multiple defects tended to have moderate myopia, a focal nerve fiber layer defect and a small optic disc (category scores 0.0932, 0.0878 and 0.0697) and were less likely to have a diffuse defect in the nerve fiber layer, emmetropia or hyperopia, and a normal disc size (category scores –0.1077, –0.0705, and –0.548). The multiple defect in the retinal nerve fiber in glaucoma was frequently focal and correlated with myopia and a small optic disc.This work was supported by grant-in-aid B-02454403 for scientific research from the Ministry of Education, Science and Culture of Japan Offprint requests to: E. Chihara