The effect of panretinal photocoagulation on confocal laser scanning ophthalmoscopy and stereo photographic parameters of optic disk topography in patients with diabetic retinopathy / Efeito da panfotocoagulação retiniana na oftalmoscopia confocal de varredura a laser e parâmetros da estereofotografia do disco óptico em pacientes com retinopatia diabética

ABSTRACT Purpose: To determine the effect of panretinal photocoagulation on optic disk topographic parameters in non-glaucomatous patients with proliferative diabetic retinopathy. Methods: This was a prospective, single-center, observational study. Thirty-eight eyes of 26 patients with diabetes underwent panretinal photocoagulation for proliferative diabetic retinopathy. Stereoscopic disk photographs and optic nerve head parameters were evaluated using the Zeiss fundus camera and the confocal scanning laser ophthalmoscope (Heidelberg Retinal Tomograph), respectively, at baseline and 12 months after the completion of panretinal photocoagulation. Results: Thirty-eight eyes of 26 patients (15 female) with a mean age of 53.7 (range 26-74) years were recruited. No significant difference was found between the stereo photography determined mean horizontal and vertical cup-to-disk ratio before and after panretinal photocoagulation treatment (p=0.461 and 0.839, respectively). The global values of the optic nerve head parameters analyzed with the HRT3 showed no significant change from baseline to 12 months, including the disk area, cup area, rim area, cup volume, rim volume, cup-to-disk area ratio, linear cup-to-disk ratio, mean cup depth, maximum cup depth, cup shape measure, height variation contour, mean retinal nerve fiber layer thickness, and cross-sectional area. Conclusion: Our results suggest that panretinal photocoagulation does not cause morphological optic disk changes in patients with diabetic proliferative retinopathy after 1 year of follow-up.

RESUMO Objetivo: Determinar o efeito da panfotocoagulação retiniana nos parâmetros topográficos do disco óptico em pacientes não glaucomatosos com retinopatia diabética proliferativa. Métodos: Este é um estudo observacional pros­pectivo e unicêntrico. Trinta e oito olhos de 26 pacientes dia­béticos foram submetidos à panfotocoagulação retiniana para retinopatia diabética proliferativa. As estereofotografias e os parâmetros do disco óptico foram avaliados usando o retinógrafo Visucam da Zeiss e o oftalmoscópio confocal de varredura a laser (Heidelberg Retinal Tomograph), respectivamente, no início e 12 meses após a conclusão da panfotocoagulação. Resultados: Trinta e oito olhos de 26 pacientes (15 mulheres) com média de idade de 53,7 anos (intervalo de 26-74) foram recrutados. Nenhuma diferença significativa foi encontrada entre a média horizontal e vertical para relação escavação/disco óptico determinadas pelas estereo­fotografias antes e após o tratamento com panfotocoagulação retiniana (p=0,461 e 0,839, respectivamente). Os valores globais dos parâmetros do disco óptico analisados com a tomografia de varredura a laser não mostraram nenhuma mudança significativa entre o início até os 12 meses, incluindo disk area, cup area, rim area, cup volume, rim volume, C/D area ratio, linear C/D ratio, mean cup depth, maximum cup depth, cup shape measure, height variation contour, mean retinal nerve fiber layer thickness e cross-sectional area. Conclusão: Nossos resultados sugerem que a panfotocoagulação retiniana não causa alterações morfológicas no disco óptico em pacientes com retinopatia diabética proliferativa após um ano de seguimento.

Análise de regressão logística na combinação de métodos propedêuticos no diagnóstico do glaucoma / Logistic regression analysis in the combination of diagnostic methods in glaucoma

OBJETIVOS: Estudar a habilidade diagnóstica do tomógrafo retiniano de Heidelberg (HRT II), GDx analisador de fibras nervosas (GDx), perimetria azul-amarelo (SWAP), tecnologia de frequência duplicada (FDT) isoladamente e em conjunto no diagnóstico do glaucoma. MÉTODOS: Sessenta glaucomatosos e 60 pacientes normais foram submetidos a exames de HRT II, GDx, SWAP e FDT. HRT foi considerado alterado quando pelo menos uma região do anel neurorretiniano esteve fora dos limites da normalidade, conforme a análise de regressão de Moorfields. GDx alterado foi definido quando pelo menos um índice foi considerado pelo programa do equipamento como fora dos limites normais, excluindo-se o índice simetria, ou ainda quando no gráfico "the deviation from normal graph" apareceu um quadrante com significância abaixo de 5%. O FDT foi considerado anormal quando pelo menos uma região testada apresentou-se com defeito severo ou com a presença de dois defeitos moderados contíguos. Para o SWAP foram adotados os critérios de anormalidade propostos por Anderson. Análise de regressão logística foi realizada. RESULTADOS: Quando foram estudadas as tecnologias isoladamente, a análise de regressão logística apresentou melhores índices de razão das chances para glaucoma com exames positivos para o HRT (22,49), seguido pelo SWAP (21,71). FDT (3,97) e GDx (2,73). Quando se associaram exames positivos de diferentes tecnologias, as razões das chances aumentaram. Nos casos com exames de HRT, FDT e SWAP fora dos limites normais, a razão das chances foi de 252,6 e com HRT, SWAP e GDx alterados, 173,1. Quando associamos exames positivos de diferentes tecnologias, a razão das chances dos pacientes serem glaucomatosos aumentou consideravelmente, chegando a 689,7 com todos os exames fora dos limites normais, o que ocorreu em 26 pacientes deste estudo. CONCLUSÕES: A análise de regressão logística confirmou que a presença de exames alterados de HRT ou SWAP apresentam as maiores razões das chances de glaucoma. A associação de exames alterados aumentou a razão das chances, principalmente, quando o HRT e o SWAP estavam fora dos limites normais.

PURPOSES: In this research was studied the diagnostic ability of the Heidelberg Retinal Tomograph (HRT II), GDx nerve fiber analyzer (GDx), Short-wavelenght Automated Perimetry (SWAP) and Frequency-doubling technology (FDT), all of them together and also separately in the diagnosis of glaucoma. METHODS: Sixty glaucomatous patients and 60 normal ones were submitted to examination with the technology of HRT II, GDx, FDT and SWAP. In the interpretation of HRT, based on the Moorfields regression analysis, were considered abnormal when at least one area of the neuroretinal ring was outside the bounds of normality. GDx was defined as altered, when it was observed that at least one index was considered by equipment program as outside of normal limits, excluding the index symmetry, or when "the deviation from normal graph" appeared a quadrant with significance below 5%. The FDT was considered abnormal when at least one region tested presented with severe defects, or two contiguous moderate defects in at least two reliable tests. For SWAP was adopted the abnormality criteria proposed by Anderson. Logistic regression analysis was performed. RESULTS: When the technologies were studied separately, the Logistic regression analysis showed better odds ratio rates to test positive for glaucoma with HRT (22.49), followed by EAP (21.71), FDT (3.97) and GDx (2.73). When positive tests were associated with different technologies, the odds ratios increased. In cases with HRT, FDT and PAA tests, outside normal bounds, the odds ratio was 252.6. Concerning the HRT, GDx and PAA the result have changed to 173.1. When we associate positive tests from different technologies, the odds ratio of glaucomatous patients have increased considerably, reaching 689.7 with all the tests outside normal bounds, which have happened with 26 patients of this study. CONCLUSIONS: The Logistic Regression analysis confirmed that the abnormal tests of HRT and PAA have shown to be the highest reasons for glaucoma occurrence. The association of abnormal tests increased the odds ratio, especially when the HRT and PAA were out of normal bounds.

Retinal nerve fiber layer in primary open-angle glaucoma with high myopia determined by optical coherence tomography and scanning laser polarimetry / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Fundus changes associated with high myopia (HM) may mask those associated with primary open-angle glaucoma (POAG). This study aim to determine the characteristics of RNFL thickness changes in patients with both POAG and HM and compare these to changes in patients with only HM. The diagnostic capabilities of both OCT and GDxVCC in this subset of patients are also evaluated.</p><p><b>METHODS</b>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. 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. 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).</p><p><b>RESULTS</b>The RNFL parameters (P < 0.05) 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.</p><p><b>CONCLUSIONS</b>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.</p>

Avaliação da camada de fibras nervosas da retina nas afecções neuroftalmológicas da via óptica anterior / Retinal nerve fiber evaluation in neuro-ophthalmic diseases of the anterior visual pathway

A avaliação da camada de fibras nervosas da retina tem grande importância no diagnóstico e acompanhamento de várias afecções da via óptica anterior. Nesta revisão, discutiremos os principais métodos de análise clínica e instrumental da camada de fibras nervosas da retina e revisamos os principais achados encontrados nas afecções da via óptica anterior incluindo lesões inflamatórias, isquêmicas, tóxicas, hereditárias, compressivas e traumáticas do nervo óptico, as lesões do quiasma óptico, as do trato óptico e aquelas do corpo geniculado lateral.

Retinal nerve fiber evaluation is important in the diagnosis and management of several diseases of the anterior visual pathway. In this report we review the clinical findings and the current techonologies avalilable to analyse the retinal nerve fiber layer. We furthermore review the main findings in several disease of the anterior visual pathways including inflammatory, ischemic, toxics, hereditary, compressive and traumatic optic neuropathies as well as lesion of the optic chiasm, optic tract and lateral geniculate body.

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 microm/yr vs. -0.218 +/- 0.151 microm/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.

Role of imaging in glaucoma diagnosis and follow-up.

The purpose of the review is to provide an update on the role of imaging devices in the diagnosis and follow-up of glaucoma with an emphasis on techniques for detecting glaucomatous progression and the newer spectral domain optical coherence tomography instruments. Imaging instruments provide objective quantitative measures of the optic disc and the retinal nerve fiber layer and are increasingly utilized in clinical practice. This review will summarize the recent enhancements in confocal scanning laser ophthalmoscopy, scanning laser polarimetry, and optical coherence tomography with an emphasis on how to utilize these techniques to manage glaucoma patients and highlight the strengths and limitations of each technology. In addition, this review will briefly describe the sophisticated data analysis strategies that are now available to detect glaucomatous change overtime.

Anterior ischemic optic neuropathy precipitated by acute primary angle closure.

A 59-year-old man with a history of longstanding systemic hypotension developed asymmetric non-arteritic anterior ischemic optic neuropathy (NAION) apparently precipitated by bilateral sequential acute primary angle closure. NAION is very rarely reported in association with raised intraocular pressure. In contrast to optical coherence tomography, the failure of scanning laser polarimetry to detect axonal swelling was another interesting finding. Possible reasoning for these observations is discussed.

Effect of cataract surgery on retinal nerve fiber layer thickness parameters using scanning laser polarimetry (GDxVCC).

Purpose: To study the effect of cataract extraction on the retinal nerve fiber layer (RNFL) thickness, and assessment by scanning laser polarimetry (SLP), with variable corneal compensation (GDx VCC), at the glaucoma service of a tertiary care center in North India. Materials and Methods: Thirty-two eyes of 32 subjects were enrolled in the study. The subjects underwent RNFL analysis by SLP (GDx VCC) before undergoing phacoemulsification cataract extraction with intraocular lens (IOL) implantation (Acrysof SA 60 AT) four weeks following cataract surgery. The RNFL thickness parameters evaluated both before and after surgery included temporal, superior, nasal, inferior, temporal (TSNIT) average, superior average, inferior average, and nerve fiber index (NFI). Results: The mean age of subjects was 57.6 ± 11.7 years (18 males, 14 females). Mean TSNIT average thickness (μm) pre- and post-cataract surgery was 49.2 ± 14.1 and 56.5 ± 7.6 (P = 0.001). There was a statistically significant increase in RNFL thickness parameters (TSNIT average, superior average, and inferior average) and decrease in NFI post-cataract surgery as compared to the baseline values. Mean NFI pre- and post-cataract surgery was 41.3 ± 15.3 and 21.6 ± 11.8 (P = 0.001). Conclusions: Measurement of RNFL thickness parameters by scanning laser polarimetry is significantly altered following cataract surgery. Post the cataract surgery, a new baseline needs to be established for assessing the longitudinal follow-up of a glaucoma patient. The presence of cataract may lead to an underestimation of the RNFL thickness, and this should be taken into account when analyzing progression in a glaucoma patient.

Scanning Laser Polarimetry and Optical Coherence Tomography for Detection of Retinal Nerve Fiber Layer Defects

PURPOSE: To compare the ability of scanning laser polarimetry with variable corneal compensation (GDx-VCC) and Stratus optical coherence tomography (OCT) to detect photographic retinal nerve fiber layer (RNFL) defects. METHODS: This retrospective cross-sectional study included 45 eyes of 45 consecutive glaucoma patients with RNFL defects in red-free fundus photographs. The superior and inferior temporal quadrants in each eye were included for data analysis separately. The location and presence of RNFL defects seen in red-free fundus photographs were compared with those seen in GDx-VCC deviation maps and OCT RNFL analysis maps for each quadrant. RESULTS: Of the 90 quadrants (45 eyes), 31 (34%) had no apparent RNFL defects, 29 (32%) had focal RNFL defects, and 30 (33%) had diffuse RNFL defects in red-free fundus photographs. The highest agreement between GDx-VCC and red-free photography was 73% when we defined GDx-VCC RNFL defects as a cluster of three or more color-coded squares (p<5%) along the traveling line of the retinal nerve fiber in the GDx-VCC deviation map (kappa value, 0.388; 95% confidence interval (CI), 0.195 to 0.582). The highest agreement between OCT and red-free photography was 85% (kappa value, 0.666; 95% CI, 0.506 to 0.825) when a value of 5% outside the normal limit for the OCT analysis map was used as a cut-off value for OCT RNFL defects. CONCLUSIONS: According to the kappa values, the agreement between GDx-VCC deviation maps and red-free photography was poor, whereas the agreement between OCT analysis maps and red-free photography was good.

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

Evaluation of Glaucomatous Damage in the Fellow Eyes of Patients With Unilateral Retinal Vein Occlusion

PURPOSE: To investigate the visual field (VF) and retinal nerve fiber layer (RNFL) status of the fellow eyes in patients with unilateral retinal vein occlusion (RVO). METHODS: Fifty patients with unilateral RVO and 35 normal control subjects wereconsecutively recruited. Humphrey VF parameters and RNFL status using scanning laser polarimetry with variable corneal compensation (GDx-VCC) were compared between the fellow eyes of the patients with unilateral RVO and control eyes. We also assessed the risk factors for the development of glaucomatous damage in the fellow eyes of unilateral RVO patients. RESULTS: Twelve fellow eyes out of 50 patients with unilateral RVO showed glaucomatous VF and RNFL changes assessed by GDx-VCC. VF indices and RNFL thickness parameters in the study group were significantly lower than those in the control group (p<0.05). Increased age and vertical cup-to-disc ratio were significantly associated with severity of VF and RNFL damage in the fellow eye of unilateral RVO patients (p<0.05). CONCLUSIONS: The fellow eyes in patients with unilateral RVO showed significantly worse VF indices and lower RNFL thickness than normal control eyes. The glaucomatous change should be carefully monitored in the fellow eyes of unilateral RVO patients.

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.

Comparison of Stratus OCT and GDx VCC in Detecting Localized Retinal Nerve Fiber Layer Defects

PURPOSE: To compare the abilities of optical coherence tomography (Stratus OCT) and scanning laser polarimetry with variable corneal compensation (GDx VCC) in detecting localized retinal nerve fiber layer (RNFL) defects of red free photography METHODS: Thirty six normal subject and 50 patients with localized RNFL defects were included in this study. Only one eye per subject was considered. The peripapillary RNFL was divided into 12 clock-hour sectors and localized RNFL defects were evaluated in these 12 sectors. To compare the diagnostic performance of Stratus OCT and GDx VCC based on the findings of red-free photography, we calculated the sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of each analyzer using a criterion of 1 > or = clock hours abnormal at the <5% level. RESULTS: The sensitivity (78.6%), specificity (94.4%), and AUC (0.872) of Stratus OCT were not significantly different from those of GDx VCC (83.3%, 94.4%, and 0.882, respectively) (McNemar test, p=0.75, 1.00, and 0.82, respectively). However, the sensitivity (64.0%) of Stratus OCT for superior RNFL defect was significantly lower than that (84.8%) for inferior defect (Fisher's exact test, p=0.02). CONCLUSIONS: The sensitivity of the sector average of Stratus OCT and the deviation map of GDx VCC were fair in discriminating localized RNFL defects, and the specificity of those were excellent. In addition, the diagnostic performance was not significantly different between two analyzers.

The Retinal Nerve Fiber Layer Analysis in Eyes with Small Optic Disc

PURPOSE: Eyes with small optic disc may be infirm to glaucomatous damage but suitable and objective methods for monitoring glaucomatous optic nerve damage in small optic disc are limited. The purpose of this study was to evaluate the usefulness of the retinal nerve fiber layer (RNFL) analysis using scanning laser polarimetry in patients with small optic disc. METHODS: 63 patients with small optic disc were recruited in this study. Eyes with average disc diameter 1.617 mm or less which was 33 percentile by topographic scanning system in our normal population study were enrolled. There were 26 patients with normal tension glaucoma and 37 patients with normal visual fields. Each patient underwent RNFL analysis using GDx VCC. Measurements of axial length, intraocular pressure, refractive error, disc diameter and cup/disc ratio were fulfilled. Findings were compared with independent t-test between 2 groups. GDx VCC parameters were analyzed with multiple logistic regression analysis. RESULTS: No differences in age, axial length, intraocular pressure, refractive error and disc diameter were apparent between the two groups. However, significant differences were detected in GDx VCC parameters including TSNIT average, Superior average, TSNIT standard deviation, NFI, Superior ratio, Inferior ratio, Sup/nasal, Maximum modualation, Superior maximum and Normalized superior area (p<0.001). The RNFL damage of superior area was prominent. CONCLUSIONS: In the patients with small optic disc, it is hard to detect the pathologic glaucomatous change by their disc morphologies. Therefore, RNFL analysis could be useful for a glaucoma screening of the patients with small optic disc.

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.

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.

Discriminating Ability of Scanning Laser Polarimetry with Variable Corneal Compensation in Normal and Glaucomatous Eyes

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.

Diagnostic Outcomes of Patients Suspicious for Glaucoma Referred from The Company Health Screening

PURPOSE: To evaluate the diagnostic outcomes of patients suspicious for glaucoma referred from the company health screening. METHODS: In this prospective study, 147 (87 male, 60 female) patients for glaucoma suspicious referred from the company health screening were enrolled. They underwent slit-lamp examination, Goldmann applanation tonometry, gonioscopy, optic disc examination, visual field examination and peripapillary retinal nerve fiber layer (RNFL) thickness measurement using optical coherence tomography (StratusOCT) and scanning laser polarimetry (GDx VCC). We analyzed their diagnostic outcomes. RESULTS: The mean age of patients was 43.8 9.6 years. Reasons for glaucoma suspicion and the number of referred patients were 111 (75.5%) high cup/disc ratio, 23 (15.6%) high intraocular pressure and 13 (8.8%) both of these. The diagnostic outcome was as follows: glaucoma, 26 (17.7%); glaucoma suspect, 4 (2.7%); ocular hypertension (OHT), 14 (9.5%); no glaucoma and no ocular hypertension, 89 (60.5%); and normal, 18 (12.2%). CONCLUSIONS: Glaucoma, glaucoma suspect and ocular hypertension were confirmed in 27.2% of patients suspicious for glaucoma referred from the company health screening. Thus, the company health screening appears to be relatively sensitive to detecting glaucoma patients.

Scanning Laser Polarimetry Using Variable Corneal Compensation in Detection of Localized Visual Field Defects

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.

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.