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.
Compensation and Redress* ; Prospective Studies ; ROC Curve ; Scanning Laser Polarimetry*

PURPOSE: To determine the effect of temporary intraocular pressure (IOP) elevation during laser in situ keratomileusis (LASIK) on retinal nerve fiber layer measurement by scanning laser polarimetry in a clinical trial. METHODS: The duration of IOP elevation was recorded during LASIK and scanning laser polarimetry (GDx(R) Retinal Nerve Fiber Analyzer. Laser Diagnostic Technologies, Inc, San Diego, California) measurements were performed in 60 eyes of 30 consecutive patients before and after the LASIK procedure. RESULTS: The mean duration of IOP elevation during LASIK was 27.2+/-4.5 seconds. The mean retinal nerve fiber layer (RNFL) thickness measured by scanning laser polarimetry were 73.2+/-12.8 micro meter preoperatively, 65.6+/-12.7 at postoperative 1 month and 66.0+/-9.8 micro meter at postopertive 3 months. The mean postoperative 1 month and 3 months values showed significantly reduced RNFL thickness. But, there was no relationship between the duration of IOP elevation and the amount of nerve fiber layer thickness reduction. (R2=0.064, p=0.627) Furthermore, there were no interval change between the retardation values of postoperative 1 month and 3 months (p=0.706). CONCLUSIONS: There was no relationship between the duration of IOP elevation during LASIK and the postoperative reduction of RNFL thickness measured by scanning laser polarimetry. When using scanning laser polarimetry as a helpful diagnostic and follow-up tool for glaucoma, care should be taken in the interpretation of the result after LASIK procedure. If a comparison is likely to be needed in the future, this image should be obtained after the LASIK procedure to set the postoperative baseline.
Follow-Up Studies ; Glaucoma ; Humans ; Intraocular Pressure ; Keratomileusis, Laser In Situ* ; Nerve Fibers* ; Retinaldehyde ; Scanning Laser Polarimetry

To evaluate the influence of diabetes mellitus (DM)on the retinal nerve fiber layer thickness, we compared the retinal nerve fiber layer thickness among four groups using Nerve Fiber Analyzer (LDT, Inc., U.S.A.).Each group of 101 patients with open-angle glaucoma (OAG)and of 91 patients without glaucoma (nonglaucomatous group)was divided into two subgroups according to the presence of DM.Fifty three nonglaucomatous eyes without DM (normal group), 38 nonglaucomatous eyes with DM, 67 OAG eyes without DM, and 34 OAG eyes with DM were included. Among 4 groups, inferior averages were the thickest, followed by the superior, nasal and temporal averages.Compared with the group with OAG without DM, only the superior average was significantly thicker in normal group (p<0.05, Student t-test).In nonglaucomatous group, the presence of diabetes caused statistically significant decrease in superior average and nasal average (p<0.05).In the group with OAG, the presence of diabetes caused statistically significant decrease in nasal average (p<0.05). In this study, we tried to measure the diabetic changes of the retinal nerve fiber layer thickness quantitatively using the scanning laser polarimetry (Nerve Fiber Analyzer), and we found that the diabetic changes in the retinal nerve fiber layer were somewhat different from those reported for glaucomatous retinal nerve fiber layer defect.
Diabetes Mellitus* ; Glaucoma ; Glaucoma, Open-Angle ; Humans ; Nerve Fibers* ; Retinaldehyde* ; Scanning Laser Polarimetry

PURPOSE: We investigated the diagnostic ability of scanning laser polarimetry with variable corneal compensation (GDx VCC) parameters to distinguish glaucomatous eyes with different degrees of visual field abnormality from normal eyes. METHODS: Subjects were divided into a control group (n=47) and an early to moderate glaucoma group (n=100). The latter included 53 early glaucoma patients (mean deviation > -6dB with a Humphrey Field Analyzer). Using a receiver operating characteristic (ROC) curve, the diagnostic power of GDx VCC parameters was analyzed and the correlations between those parameters and Humphrey Field Analyzer (HFA) indices were statistically analyzed. RESULTS: Nerve fiber indicator (NFI) provided the best discriminating ability with the highest area under the ROC curve (AUROC) value for detecting eyes with early to moderate perimetric glaucoma. TSNIT average showed the highest AUROC value for detecting eyes with early perimetric glaucoma. The optimal NFI cut-off value to discriminate between the control group and early to moderate group was 22, offering the best combination of sensitivity (88.0%) and specificity (83.0%). The optimal TSNIT average cut-off value to discriminate between the control group and early glaucoma group was 53.49 micrometer, providing the best combination of sensitivity (84.9%) and specificity (85.1%). Most of the thickness parameters showed higher AUROC values than those of the ratio or modulation parameters. A statistically significant correlation was found between the GDx VCC parameters and HFA indices. CONCLUSIONS: Measurement of the retinal nerve fiber layer (RNFL) by scanning laser polarimetry with variable corneal compensation is useful in discriminating between normal and glaucomatous eyes.
Compensation and Redress* ; Glaucoma ; Humans ; Nerve Fibers ; Retinaldehyde ; ROC Curve ; Scanning Laser Polarimetry* ; Sensitivity and Specificity ; Visual Fields

PURPOSE: To study the unaffected fellow eye in patients with normal tension glaucoma and unilateral visual field defect in conventional white-on-white automated perimetry, using scanning laser polarimetry and frequency-doubling perimetry. METHODS: Thirty patients with a unilateral glaucomatous visual field defect detected on conventional perimetry (Humphrey field analyzer) were selected. The contralateral eyes with normal conventional perimetry results were studied using scanning laser polarimetry and frequency-doubling perimetry. Twenty eyes of 20 age- (+/-5 years), sex-, refractive error- (+/-2 D) matched persons without glaucoma were selected as a control group. RESULTS: Of the 30 contralateral eyes, 18 eyes (60%) showed a defect of the nerve fiber layer when evaluated with SLP. In the control group, 2 eyes (8.3%) showed a defect of the nerve fiber layer. Of the 20 contralateral eyes, 14 eyes showed abnormal FDP results. In the 17 control group, 2 eyes (2%) showed abnormal FDP results. CONCLUSIONS: These findings suggest that what appeared to be unilateral visual field defects by conventional white-on-white automated perimetry may in fact underestimate structural as well as functional glaucomatous damage in the contralateral eyes. These results may be important for early detection of glaucoma and future treatment.
Glaucoma ; Humans ; Low Tension Glaucoma* ; Nerve Fibers ; Scanning Laser Polarimetry ; Visual Field Tests ; Visual Fields*

PURPOSE: To evaluate the ability of scanning laser polarimetry parameters and a novel deviation-map algorithm to discriminate between healthy and early glaucomatous eyes with localized visual field defects confined in one hemifield. METHODS: In this prospective case-controlled study, 61 glaucomatous eyes with localized visual field defects and 66 normal controls were enrolled. Humphrey field analyzer 24-2 glaucoma hemifield test and scanning laser polarimetry (GDx-VCC ) were used. RESULTS: There were significant differences in the mean parametric values of TSNIT average, superior average, inferior average, and TSNIT SD (P<0.05) between the glaucoma group and normal subjects. The sensitivity of each GDx-VCC variable was as follows: TSNIT average, 47.5%; superior average, 31.1%; inferior average, 47.5%; and TSNIT SD, 24.6% (when abnormal was defined as P<0.05). The overall sensitivities combining each probability scale and severity score at 80%, 90%, and 95% specificity were 90.2%, 72.1%, and 59%, respectively. There was a statistically significant correlation between the GDx-VCC severity score and the visual field severity score (P<0.05). CONCLUSIONS: GDx-VCC parameters may not be sufficiently sensitive to detect glaucomatous patients with localized visual field damage. Our algorithm using the GDx-VCC deviation map may enhance the understanding of GDx-VCC in terms of the locality, deviation size, and severity of localized RNFL defects in eyes with localized visual field loss.
Case-Control Studies ; Compensation and Redress* ; Glaucoma ; Humans ; Prospective Studies ; Scanning Laser Polarimetry* ; Sensitivity and Specificity ; Visual Fields*

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.
Cataract* ; Cornea ; Glaucoma ; Humans ; Nerve Fibers* ; Retinaldehyde ; Scanning Laser Polarimetry ; Visual Fields

Methods: Patients with and without glaucoma underwent a complete eye evaluation, automated perimetry, scanning laser polarimetry with the GDx 400, and opticdisc photography. Two glaucoma experts graded each study eye. Two-by-two tables were constructed for 5 GDx parameters (average thickness, superior average, inferior average, ellipse average, and ellipse modulation) and the CDx number. Receiver operating characteristic (ROC) curves were generated. Results: The study included 355 patients (171 normal, 184 glaucoma). The mean values of the 5 GDx parameters were lower for the glaucoma than for the normal group. The sensitivity and specificity of the GDx 400 were 45.4 percent and 91.9 percent if the cut off level of the GDx number was 71. Ellipse modulation (EM) measures have the best ROC curve with area under the curve of 0.725. Conclusion: The GDx 400 nerve-fiber analyzer is primarily used as a screening tool to detect the presence or absence of glaucoma. Its accuracy can be improved with use of continuous corneal compensator.
Human ; Male ; Female ; Aged ; Middle Aged ; Adult ; GLAUCOMA ; RETINA ; NERVE FIBERS ; SCANNING LASER POLARIMETRY ;

PURPOSE: To evaluate the difference of retinal nerve fiber layer measurements as obtained by Nerve Fiber Analyser according to visual field defects in subjects with large Cup-to-Disc ratio (C/D ratio>or=0.6) and to determine which predictable parameters are useful in glaucoma diagnosis. METHODS: Fifty one normal subjects, 17 patients with glaucoma, 18 glaucoma suspects based on optic disc appearance and visual field defect participated. Nerve fiber layer thickness assessments using scanning laser polarimeter (Nerve Fiber Analyzer II software version 2.1.; Laser Diagnostic Technologies, Inc., San Diego, California, U.S.A.) were measured in normal subjects, patients with glaucoma, and glaucoma suspects. Measured nerve fiber layer thickness parameters were compared each other. RESULTS: Superior to inferior ratio (S/I ratio) was only statistically significant parameter to differentiate glaucoma from glaucoma suspects having glaucomatous optic nerve head. CONCLUSIONS: Superior to inferior ratio (S/I ratio) is useful parameter to predict differentiating patients with glaucoma from glaucoma suspects.
California ; Diagnosis ; Glaucoma* ; Humans ; Nerve Fibers* ; Optic Disk ; Retinaldehyde* ; Scanning Laser Polarimetry ; Visual Fields

PURPOSE: To evaluate the usefulness of the retinal nerve fiber layer thickness and peripapillary atrophy in discrimination between normal and glaucoma patients with small optic discs which can be potentially misleading by cup-to-disc ratio. METHODS: Eyes with average disc diameter 1.617 mm or less which is 33 percentile by topographic scanning system (TopSST M, version 2.2, LDT, Inc., U.S.A) in our normal population study were enrolled. 82 eyes of 82normal subjects, 30 eyes of 30 patients with primary open-angle glaucoma (POAG), 16 eyes of 16 patientswith normal tension glaucoma (NTG) were studied. Program 30-2 of the Humphrey Field and scanning laser polarimetry (Nerve Fiber Analyzer II : NFAII, version 2.1., LDT, Inc., U.S.A.) were performed and color optic disc photographs had been taken. The differences in NFA parameters and peripapillary atrophy (zone alpha and zone beta) between normal subjects and glaucoma patients were examined. RESULTS: Considering all the NFA parameters, superonasal ratio of POAG and NTG group was significantly lower than normal group (p=0.002, p=0.043, respectively) and inferonasal ratio of POAG group was significantly lower than normal group (p=0.020). Zone beta atrophy was detected more frequently in POAG and NTG group than normal group (p=0.015, 0.007, respectively). No significant correlation was found between superonasal, inferonsal ratio and visual field indices and the presence of zone beta was not associated with progression of visual field. CONCLUSIONS: In small optic discs which had been presented diagnostic difficulties with optic disc status, retinal nerve fiber layer thickness (superonasal or inferonasal ratio) and/or peripapillary atrophy (zone beta) analysis can be helpful in identifying glaucoma.
Atrophy* ; Discrimination (Psychology) ; Glaucoma* ; Glaucoma, Open-Angle ; Humans ; Low Tension Glaucoma ; Nerve Fibers* ; Retinaldehyde* ; Scanning Laser Polarimetry ; Visual Fields