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.

Longitudinal Analysis of Retinal Nerve Fiber Layer Thickness With GDx-VCC in Glaucoma Suspect

PURPOSE: The changes of retinal nerve fiber layer thickness with GDx-VCC were analyzed to assess the use of this instrument for longitudinal follow-up of retinal nerve fiber layers. METHODS: From July 2004 to July 2007, patients suspected of glaucoma were measured with GDx-VCC at baseline and measurements were repeated at a minimum interval of 12 months. The medical records of 150 patients were reviewed and 42 patients that showed glaucomatous visual field progression in 36 months were classified into a "progression group" and 108 patients with no visual field loss were classified into a "nonprogression group". RESULTS: In the nonprogression group, the temporal superior-nasal-inferior-temporal (TSNIT) average and theinferior average showed statistically significant changes for the follow up periods. However, in theprogression group, there were no parameters with significant changes even though glaucomatous visual field loss was found. The visual field progressed at a rate of 0.1dB/year in the progression group but the relationship between MD, PSD and GDx-VCC parameters could not be established. CONCLUSIONS: GDx-VCC may not be sufficient for longitudinal assessment of the RNFL, especially during the early glaucomatous visual field changes. The progression of glaucoma only with GDx-VCC should be cautiously evaluated, and confirmation with the visual field which elucidates early glaucomatous changes is necessary. Further study is needed before GDx-VCC can be recommended as the instrument for longitudinal assessment.

Structural and Functional Relationships in Glaucoma Using Standard Automated Perimetry and the Humphrey Matrix

PURPOSE: To evaluate and compare correlations between structural and functional loss in glaucoma as assessed by optical coherence tomography (OCT), scanning laser polarimetry (GDx VCC, as this was the model used in this study), standard automated perimetry (SAP), and the Humphrey Matrix (Matrix). METHODS: Ninety glaucomatous eyes identified with SAP and 112 eyes diagnosed using Matrix were independently classified into six subgroups, either S1/M1 (MD>-6dB), S2/M2 (-12

Changes in RNFL Thickness According to the Myopia in Patients with Glaucoma and Ocular Hypertension

PURPOSE: To evaluate the changes in retinal nerve fiber layer (RNFL) thickness according to the degree of myopia in patients with glaucoma and ocular hypertension. METHODS: Ninety-eight patients (165 eyes) diagnosed with glaucoma or ocular hypertension underwent optical coherence tomography (OCT) and scanning laser polarimetry using variable corneal compensation (GDx-VCC) to analyze the correlation between the degree of myopia and the thickness of the RNFL. A partial correlation coefficient analysis was performed to adjust for various factors such as age, laterality, intraocular pressure, and the mean deviation from visual field test, which can influence the RNFL thickness. RESULTS: The average, nasal, superior, and inferior sectorial RNFL thicknesses measured by OCT significantly decreased with increasing myopia (p<0.05). However, RNFL thickness measured by GDx-VCC was not significantly correlated with the degree of myopia. CONCLUSIONS: The RNFL thickness measured by OCT decreased with increasing myopia in eyes with glaucoma and ocular hypertension.

Relationship between Scanning Laser Polarimetry with Enhanced Corneal Compensation and with Variable Corneal Compensation

PURPOSE: To evaluate the structure-function relationships between retinal sensitivity measured by Humphrey visual field analyzer (HVFA) and the retinal nerve fiber layer (RNFL) thickness measured by scanning laser polarimetry (SLP) with variable corneal compensation (VCC) and enhanced corneal compensation (ECC) in glaucomatous and healthy eyes. METHODS: Fifty-three eyes with an atypical birefringence pattern (ABP) based on SLP-VCC (28 glaucomatous eyes and 25 normal healthy eyes) were enrolled in this cross-sectional study. RNFL thickness was measured by both VCC and ECC techniques, and the visual field was examined by HVFA with 24-2 full-threshold program. The relationships between RNFL measurements in superior and inferior sectors and corresponding retinal mean sensitivity were sought globally and regionally with linear regression analysis in each group. Coefficients of the determination were calculated and compared between VCC and ECC techniques. RESULTS: In eyes with ABP, R2 values for the association between SLP parameters and retinal sensitivity were 0.06-0.16 with VCC, whereas they were 0.21-0.48 with ECC. The association of RNFL thickness with retinal sensitivity was significantly better with ECC than with VCC in 5 out of 8 regression models between SLP parameters and HVF parameters (P<0.05). CONCLUSIONS: The strength of the structure-function association was higher with ECC than with VCC in eyes with ABP, which suggests that the ECC algorithm is a better approach for evaluating the structure-function relationship in eyes with ABP.

Achados oftalmológicos em pacientes que receberam transplante cardíaco / Ophthalmologic findings in cardiac transplant recipients

OBJETIVO: Avaliar os achados oculares, pelo exame oftalmológico, em indivíduos que receberam transplante cardíaco, buscando especialmente investigar possíveis alterações na camada de fibras nervosas da retina com polarímetro de varredura a laser. MÉTODOS: Foram estudados 15 indivíduos que receberam transplante cardíaco no período de setembro de 2003 a julho de 2004. Todos foram submetidos a exame que constava de acuidade visual para longe (AVL), biomicroscopia, tonometria e fundoscopia. Onze pacientes foram submetidos ao analisador de fibras nervosas GDx. Doze eram do sexo masculino e a média da idade foi de 55,0 ± 13,5 anos. O tempo decorrido desde o transplante variou de 3 a 74 meses, com média de 29,7 ± 20,8 meses. RESULTADOS: A AVL com melhor correção foi igual ou melhor do que 20/40 em todos os pacientes. Em um deles observou-se a presença de catarata subcapsular posterior; em outro, nubéculas na córnea secundárias a quadro de herpes zoster. À fundoscopia pôde-se observar lesão cicatrizada sugestiva de retinocoroidite em um paciente. As alterações observadas à biomicroscopia e à fundoscopia eram esperadas devido à imunossupressão subseqüente ao transplante. Ao GDx observou-se perda de fibras da camada de fibras nervosas da retina superior em 12 dos 22 olhos avaliados. CONCLUSÃO: Os resultados apóiam a suposição de que antes ou durante o transplante cardíaco tenha havido diminuição no aporte de oxigênio à circulação retiniana, levando a perda parcial de fibras da retina.

PURPOSE: To evaluate findings of ophthalmologic examinations in cardiac transplant recipients, searching especially for changes in the retinal nerve fiber layer by means of Scanning Laser Polarimetry. METHODS: Fifteen cardiac transplant recipients were examined from September 2003 to July 2004. All of them underwent ophthalmologic examination, which consisted of visual acuity (VA), biomicroscopy, tonometry and fundoscopy. Fiber layer analyzer - GDx - examination was performed in eleven patients. Twelve patients were men. The mean age was 55.0 ± 13.5 years. The follow-up since transplantation lasted from 3 to 74 months; mean value 29.7 ± 20.8 months. RESULTS: VA with best correction in all patients attained at least 20/40. Subcapsular posterior cataract was seen in one patient; another presented corneal nubeculae secondary to herpes zoster. In one case a scar suggesting retinocoroiditis was seen at fundoscopy. Biomicroscopic and the fundoscopic findings were expected because of immunosuppressive treatment, following transplantation. GDx examination disclosed loss of fibers in the superior retinal fiber layer in 12 of the 22 examined eyes. CONCLUSION: These results support the hypothesis that reduction of oxygen inflow in retinal circulation before or during heart transplantation could lead to loss of fibers in the retinal nerve fiber layer.

GDx-VCC Performance to Discriminate Normal, Pre-perimetric Glaucomatous Eyes

PURPOSE: This study was designed to assess the diagnostic value of scanning laser polarimetry with variable corneal compensation (GDx-VCC) in the diagnosis of preperimetric glaucoma. METHODS: The study included 132 eyes of 132 patients with normal intraocular pressure, including 38 normal eyes, 60 eyes with pre-perimetric glaucoma, and 34 eyes with early glaucoma. The parameters of GDx-VCC were analyzed and compared in these groups using ANOVA. The parameter with the most powerful diagnostic value was defermirred by an ROC curve, and it's sensitivity and specificity were calculated. RESULTS: Among GDx-VCC parameters, NFI was the most valuable parameter that could detect pre-perimetric glaucoma in normal eyes. A cut-off value of 12 was the optimal NFI value, which offered the highest sensitivity and specificity in discriminating between normal and pre-perimetric glaucomatous eyes. However, there were no statistically significant differences in GDx-VCC parameters between pre-perimetric and early glaucomatous eyes. A statistically significant correlation was found between NFI and visual field indices in early glaucomatous eyes. CONCLUSIONS: GDx-VCC can be useful as a screening test for early detection of pre-perimetric and early glaucoma with normal intraocular pressure.

Diagnostic Ability of Scanning Laser Polarimetry with Enhanced Corneal Compensation in the Eye with Typical and Atypical Retadation Pattern

PURPOSE: To investigate the relationship between the SLP-VCC parameters and the SLP-ECC parameters in the eyes with typical retardation pattern (TRP) and atypical retardation pattern (ARP), and the sensitivities and specificities of the SLP-VCC parameters and the SLP-ECC parameters in the eye with TRP and ARP. METHODS: In this prospective study, 72 eyes with TRP images (30 glaucomatous and 42 normal eyes) and 53 eyes with ARP images (28 glaucomatous and 25 normal eyes) were recruited. For each group, we analyzed relationship between each parameters of GDx-VCC and GDx-ECC and the diagnostic ability of GDx-ECC by using the ROC curve. RESULTS: In the eyes with TRP, TSNIT average was significantly lower by GDx-ECC than GDx-VCC in the control group. Inferior average was significantly higher by GDx-ECC than GDx-VCC in both glaucomatous and normal group. TSNIT standard deviation was significantly higher by GDx-ECC than GDx-VCC in both groups. NFI was significantly lower by GDx-ECC than GDx-VCC in both groups. TSS (typical scan score) was significantly higher by GDx-ECC than GDx-VCC in both groups. In the eyes with ARP, TSNIT average was significantly lower by GDx-ECC than GDx-VCC in both groups. Superior and Inferior average was not different between GDx-ECC and GDx-VCC. TSNIT standard deviation was significantly higher by GDx-ECC than GDx-VCC in both groups. NFI was not different between groups. TSS was significantly higher by GDx-ECC than GDx-VCC in both groups. Comparison of ROC curve for the SLP parameters revealed no difference between VCC and ECC. TSNIT standard deviation, however, showed relatively high value in GDx-ECC compared with GDx-VCC. CONCLUSIONS: GDx-ECC has comparable diagnostic ability in discriminating glaucomatous and normal eyes with GDx-VCC and TSNIT standard deviation by the GDx-ECC algorithm could be a useful parameter in discriminating glaucomatous and normal eyes.

The Comparison of Detecting RNFL using GDX and OCT / 医学研究杂志

Objective To estimate the general power of OCT and GDX in the detection of glaucoma on the item of retinal nerve fiber layer thickness.Methods 42 patients(80eyes)underwent OCT and GDX.To compare the results.Results There was significant difference between the two methods.but they had significant plus correlation.Conclusions The sensitivity and agreement of GDX in the examination of RNFL is quite good compared with OCT for the detection of glaucoma.

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.

The Relationship between Optical Coherence Tomography and Scanning Laser Polarimetry Measurements in Glaucoma

PURPOSE: To investigate the relationship between optical coherence tomography (OCT) and scanning laser polarimetry (SLP) in measuring peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous eyes. METHODS: Fifty glaucomatous eyes were evaluated in this study. Evaluations were analyzed two ways. First, parameters of the Stratus OCT (average thickness, superior/ inferior average) and GDx VCC (TSNIT average, nerve fiber indicator (NFI), superior/ inferior average) were correlated using the Pearson's correlation coefficient (r). Secondly, comparison (r) of these parameters was completed using the mean deviation (MD) of visual field defect. RESULTS: The following parameters were found to be significantly correlated (P<0.005). TSNIT average/average thickness (r=0.673), NFI/average thickness (r=-0.742), superior average (r=0.841), and inferior average (r=0.736). In the correlation analysis using the severity of visual field defect, all these parameters had statistically meaningful correlations (P<0.005). CONCLUSIONS: GDx VCC and Stratus OCT are highly correlated in glaucomatous eyes. Therefore, peripapillary RNFL thickness measured by Stratus OCT and GDx VCC may be equally helpful in the diagnosis of glaucoma.

Influence of Lens Opacity on Nerve Fiber Layer Analysis in Glaucomatous and Normal Eyes

PURPOSE: To analyze the retinal nerve fiber layer in glaucoma eyes and in normal eyes, before and after cataract surgery using GDx (Laser Diagnostic Technologies, Inc., San Diego, CA, U.S.A), - a scanning laser polarimetry, and to evaluate the effect of lens opacity on retinal nerve fiber layer analysis. METHODS: Ocular examination and GDx analysis were performed one month before and after cataract surgery on 16 eyes of 10 patients affected with glaucoma and 14 normal eyes of 9 patients at St. Mary's Hospital. Regarding the eyes affected with glaucoma, only those who showed no evidence of glaucoma progression on a visual field examination before and after the cataract surgery were included, and every cataract surgery was performed perfectly. Comparisons of the GDx parameters before and after cataract surgery were performed using the Wincoxon signed rank test. RESULTS: All GDx parameters before and after cataract surgery in normal eyes showed no significant differences. In the glaucoma patients, differences in symmetry (p=0.047), superior ratio (p=0.007), ellipse modulation (p=0.001), and GDx number (p=0.008) were statistically significant. CONCLUSIONS: GDx is an examination based on the birefringent nature of retinal nerve fiber layer so the values can change according to changes in the cornea and lens, which are birefringent. This study compared the GDx parameters before and after cataract surgery of glaucoma patients and normal eyes. Our results showed that lens opacity has a minor and subtle effect on GDx parameters, and indicated the most sensitive parameters that reflect the change of retinal nerve fiber layer. Further studies should be performed using a larger sample with statistical support.

Normal Retinal Nerve Fiber Layer Thickness in the Peripapillary Region of Koreans Measured by Scanning Laser Polarimeter

PURPOSE: To measure normal retinal nerve fiber layer thickness (RNFLT) in the peripapillary region of Koreans using a scanning laser polarimeter, the nerve fiber analyzer (GDx VCC). METHODS: Two hundred ninety-nine eyes of 299 healthy subjects (156 men, 143 women) were recruited for this study. No subject had diabetes mellitus, hypertension, or any other neurologic disorders. All subjects were normal at ophthalmologic examination, which was assessed by slit-lamp biomicroscopy using a 90-diopter lens, Goldmann applanation tonometry, and Humphrey visual field analysis. Using the GDx VCC, we analyzed the mean value of each parameter in GDx VCC (average at global, superior, inferior, superior maximum and inferior maximum) and evaluated the difference between men and women and each decade of age. RESULTS: Mean RNFLT parameters in GDx VCC were global 56.42 +/- 6.84 micrometer, superior 70.51 +/- 8.70 micrometer, inferior 67.55 +/- 9.04 micrometer, superior maximum 83.52 +/- 12.38 micrometer, and inferior maximum 82.64 +/- 12.70 micrometer. The parameters which showed a difference between men and women were superior average and superior and inferior maximum average RNFLT. The superior RNFLT was thicker than the inferior ones. RNFLT was not statistically different in each decade of age. CONCLUSIONS: We can make good use of the normal parameters of GDx VCC in Koreans for early diagnosis and follow-up of glaucoma.

Diagnosis of Glaucoma in the Cases of the Opposed Results of GDx and OCT

PURPOSE: To investigate the coincidence of visual field loss in cases with different GDx VCC and Stratus OCT results, and to analyze the cause of these differences. METHODS: We retrospectively reviewed the medical records of patients who had visited our hospital for glaucoma evaluation from September 2003 to August 2005 for sensitivity, specificity, positive predictive rate, and negative predictive rate of GDx and OCT. In order to analyze the cause of discrepancy between the GDx and OCT results, we divided patients into Group A, consisting of GDx abnormal and OCT normal eyes, and Group B, consisting of GDx normal and OCT abnormal eyes. We compared optic disc tilting, peripapillary atrophy, and cup-disc ratio between the two groups. RESULTS: In cases of differing results between GDx and OCT, sensitivity, specificity, positive predictive rate and negative predictive rate were higher in Stratus OCT than in GDx. Peripapillary atrophy did not represent a statistically significant difference between group A and group B (p=0.601), where as the difference in cup-disc ratio between the two groups was statistically significant (p=0.000). CONCLUSIONS: OCT parameters coincided better than GDx with cases having different results on GDx and OCT. In cases with a large cup/disc ratio, there was a tendency to be normal according to GDx and abnormal by OCT.

Ability of Scanning Laser Polarimetry (GDx) to Discriminate among Early Glaucomatous, Ocular Hypertensive and Normal Eyes in the Korean Population

We investigated the ability of the GDx-Nerve Fiber Analyzer (NFA) to discriminate between normal and early glaucomatous eyes among Korean individuals by reviewing the medical records of 217 consecutive subjects: 61 early glaucoma patients, 68 ocular hypertensive patients, and 88 normal subjects. GDx parameters were compared using ANOVA. The Receiver Operating Characteristics (ROC) curve for each GDx-NFA variable was used to diagnose each parameter, and Pearson correlation coefficients were calculated to assess the association between GDx-NFA parameters and visual field indices in early glaucoma. The best GDx parameters to discriminate between early glaucomatous and normal subjects were the number, maximum modulation, ellipse modulation and inferior ratio (i.e. area under the ROC curve > 0.8). A value for the Number of equal to or greater than 27 was optimal for detecting early glaucoma, with a sensitivity of 80.3% and specificity of 80.7%. In addition, symmetry was positively correlated with the corrected pattern standard deviation (CPSD) among visual field indices in early glaucoma.

Interocular comparison of nerve fiber layer thickness and its relation with optic disc size in normal subjects

We conducted an investigation of the relation between RNFL thickness and optic disc size along with an interocular comparison of optic disc size, RNFL thickness, and RNFL density in healthy subjects. A total of 64 normal eyes from 32 Korean volunteers were enrolled in this study. A GDx Nerve Fiber Analyzer with software version 2.0.09 was used to image all subjects. Optic disc size was measured by pi x (horizontal radius) x (vertical radius). The RNFL density of each quadrant was calculated by dividing each quadrant integral by the total integral. Optic disc size was positively correlated with the total RNFL thickness (r = 0.615, p < 0.01). Optic disc size and RNFL density were inversely related in the superior quadrant (r = -0.248, p < 0.05). There was a significant positive correlation between optic disc size and RNFL density in the nasal quadrant (r = 0.439, p < 0.01) and the temporal quadrant to a certain degree. A significant positive correlation was found between the right and left eyes in terms of total RNFL thickness in and that of each quadrant. Interocular RNFL density was positively correlated in both the temporal and nasal quadrants. These findings must be considered when one evaluates and compares RNFL measurements between two eyes as is often the case where both eyes are usually affected in the course of glaucomatous RNFL damage.

The Parameters of the Retinal Nerve Fiber Layer Measured with Confocal Scanning Laser Ophthalmoscope & Nerve Fiber Analyzer

Assessment of the optic nerve head or the retinal nerve fiber layer is essential for the early diagnosis and monitoring of glaucoma. We compared mean retinal nerve fiber layer[RNFL]thickness with Average, and compared RNFL CSA with Integral between Heidelberg Retina Tomograph[HRT] and GDx nerve fiber analyzer[GDx]at global, superior, inferior, nasal and temporal area. Mean RNFL thickness in HRT was significantly greater than Average in GDx at all quadrants[p<0.001], and correlated with Average at global, superior and inferior area[p<0.05]. RNFL CSA in HRT was significantly greater than Integral in GDx at superior, inferior and nasal quadrants[p<0.001], and correlated with Integral at superior and inferior quadrants[p<0.05]. In conclusion, the two parameters related to nerve fiber layer in HRT were measured greater than those in GDx. Correlations of the above parameters between HRT and GDx were mainly present at superior and inferior quadrant. These results may come from regional difference in measurement between HRT and GDx, and uncorrected disc tilting in HRT appears to have adverse effects on the correlations of the above parameters between HRT and GDx at nasal or temporal quadrant.