Comparing Cone Structure and Function in RHO- and RPGR-Associated Retinitis Pigmentosa.

Purpose: To study cone structure and function in patients with retinitis pigmentosa (RP) owing to mutations in rhodopsin (RHO), expressed in rod outer segments, and mutations in the RP-GTPase regulator (RPGR) gene, expressed in the connecting cilium of rods and cones. Methods: Four eyes of 4 patients with RHO mutations, 5 eyes of 5 patients with RPGR mutations, and 4 eyes of 4 normal subjects were studied. Cone structure was studied with confocal and split-detector adaptive optics scanning laser ophthalmoscopy (AOSLO) and spectral-domain optical coherence tomography. Retinal function was measured using a 543-nm AOSLO-mediated adaptive optics microperimetry (AOMP) stimulus. The ratio of sensitivity to cone density was compared between groups using the Wilcoxon rank-sum test. Results: AOMP sensitivity/cone density in patients with RPGR mutations was significantly lower than normal (P < 0.001) and lower than patients with RHO mutations (P < 0.015), whereas patients with RHO mutations were similar to normal (P > 0.9). Conclusions: Retinal sensitivity/cone density was lower in patients with RPGR mutations than normal and lower than patients with RHO mutations, perhaps because cones express RPGR and degenerate primarily, whereas cones in eyes with RHO mutations die secondary to rod degeneration. High-resolution microperimetry can reveal differences in cone degeneration in patients with different forms of RP.

Complex vectorial optics through gradient index lens cascades.

Graded index (GRIN) lenses are commonly used for compact imaging systems. It is not widely appreciated that the ion-exchange process that creates the rotationally symmetric GRIN lens index profile also causes a symmetric birefringence variation. This property is usually considered a nuisance, such that manufacturing processes are optimized to keep it to a minimum. Here, rather than avoiding this birefringence, we understand and harness it by using GRIN lenses in cascade with other optical components to enable extra functionality in commonplace GRIN lens systems. We show how birefringence in the GRIN cascades can generate vector vortex beams and foci, and how it can be used advantageously to improve axial resolution. Through using the birefringence for analysis, we show that the GRIN cascades form the basis of a new single-shot Müller matrix polarimeter with potential for endoscopic label-free cancer diagnostics. The versatility of these cascades opens up new technological directions.

Polarization Variability in Age-related Macular Degeneration.

SIGNIFICANCE: Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss. Complementary imaging techniques can be used to better characterize and quantify pathological changes associated with AMD. By assessing specific light-tissue interactions, polarization-sensitive imaging can be used to detect tissue disruption early in the disease process. PURPOSE: The aim of this study was to compare variability in central macular polarization properties in patients with nonexudative AMD and age-matched control subjects. METHODS: A scanning laser polarimeter (GDx, LDT/CZM) was used to acquire 15 × 15-degree macular images in 10 subjects diagnosed with nonexudative AMD and 10 age-matched control subjects. The coefficient of variation (COV, SD/mean) was used to quantify variability in pixel intensity in the central 3.3° of the macula for custom images emphasizing multiply scattered light (the depolarized light image) and polarization-retaining light (the maximum of the parallel detector image). The intensity COV was compared across subject categories using paired t tests for each image type. RESULTS: The COV in the central macula was significantly higher in the AMD subject group (average, 0.221; 95% confidence interval [CI], 0.157 to 0.265) when compared with matched control subjects (average 0.120; 95% CI, 0.107 to 0.133) in the depolarized light image (P = .01). The COV in the maximum of the parallel detector image was not statistically different between the two subject groups (AMD average, 0.162 [95% CI, 0.138 to 0.185]; control average, 0.137 [95% CI, 0.115 to 0.158]; P = .21). CONCLUSIONS: Variability in multiply scattered light is higher than that of light that is more polarization preserving in patients with nonexudative AMD. Multiple scattering may act as an early indicator representing disruption to the macula in early AMD.

Predictive Factors for Visual Field Conversion: Comparison of Scanning Laser Polarimetry and Optical Coherence Tomography.

PURPOSE: The purpose of this study was to compare the ability of scanning laser polarimetry (SLP) and spectral-domain optical coherence tomography (SD-OCT) to predict future visual field conversion of subjects with ocular hypertension and early glaucoma. METHODS: All patients were recruited from the Erlangen glaucoma registry and examined using standard automated perimetry, 24-hour intraocular pressure profile, and optic disc photography. Peripapillary retinal nerve fiber layer thickness (RNFL) measurements were obtained by SLP (GDx-VCC) and SD-OCT (Spectralis OCT). Positive and negative predictive values (PPV, NPV) were calculated for morphologic parameters of SLP and SD-OCT. Kaplan-Meier survival curves were plotted and log-rank tests were performed to compare the survival distributions. Contingency tables and Venn-diagrams were calculated to compare the predictive ability. RESULTS: The study included 207 patients-75 with ocular hypertension, 85 with early glaucoma, and 47 controls. Median follow-up was 4.5 years. A total of 29 patients (14.0%) developed visual field conversion during follow-up. SLP temporal-inferior RNFL [0.667; 95% confidence interval (CI), 0.281-0.935] and SD-OCT temporal-inferior RNFL (0.571; 95% CI, 0.317-0.802) achieved the highest PPV; nerve fiber indicator (0.923; 95% CI, 0.876-0.957) and SD-OCT mean (0.898; 95% CI, 0.847-0.937) achieved the highest NPV of all investigated parameters. The Kaplan-Meier curves confirmed significantly higher survival for subjects within normal limits of measurements of both devices (P<0.001). Venn diagrams tested with McNemar test statistics showed no significant difference for PPV (P=0.219) or NPV (P=0.678). CONCLUSIONS: Both GDx-VCC and SD-OCT demonstrate comparable results in predicting future visual field conversion if taking typical scans for GDx-VCC. In addition, the likelihood ratios suggest that GDx-VCC's nerve fiber indicator<30 may be the most useful parameter to confirm future nonconversion. (http://www.ClinicalTrials.gov number, NTC00494923; Erlangen Glaucoma Registry).

Three-Dimensional Geometry of Collagenous Tissues by Second Harmonic Polarimetry.

Collagen is a biological macromolecule capable of second harmonic generation, allowing label-free detection in tissues; in addition, molecular orientation can be determined from the polarization dependence of the second harmonic signal. Previously we reported that in-plane orientation of collagen fibrils could be determined by modulating the polarization angle of the laser during scanning. We have now extended this method so that out-of-plane orientation angles can be determined at the same time, allowing visualization of the 3-dimensional structure of collagenous tissues. This approach offers advantages compared with other methods for determining out-of-plane orientation. First, the orientation angles are directly calculated from the polarimetry data obtained in a single scan, while other reported methods require data from multiple scans, use of iterative optimization methods, application of fitting algorithms, or extensive post-optical processing. Second, our method does not require highly specialized instrumentation, and thus can be adapted for use in almost any nonlinear optical microscopy setup. It is suitable for both basic and clinical applications. We present three-dimensional images of structurally complex collagenous tissues that illustrate the power of such 3-dimensional analyses to reveal the architecture of biological structures.

Evaluation of intraretinal migration of retinal pigment epithelial cells in age-related macular degeneration using polarimetric imaging.

The purpose of the present study was to evaluate the intraretinal migration of the retinal pigment epithelium (RPE) cells in age-related macular degeneration (AMD) using polarimetry. We evaluated 155 eyes at various AMD stages. Depolarized light images were computed using a polarization-sensitive scanning laser ophthalmoscope (PS-SLO), and the degree of polarization uniformity was calculated using polarization-sensitive optical coherence tomography (OCT). Each polarimetry image was compared with the corresponding autofluorescence (AF) images at 488 nm (SW-AF) and at 787 nm (NIR-AF). Intraretinal RPE migration was defined by the presence of depolarization at intraretinal hyperreflective foci on PS-SLO and PS-OCT images, and by the presence of hyper-AF on both NIR-AF and SW-AF images. RPE migration was detected in 52 of 155 eyes (33.5%) and was observed in drusenoid pigment epithelial detachment (PED) and serous PED with significantly higher frequencies than in other groups (P = 0.015). The volume of the migrated RPE cluster in serous PED was significantly correlated with the volume of the PED (R2 = 0.26; P = 0.011). Overall, our results showed that intraretinal RPE migrations occurred in various AMD stages, and that they occurred more commonly in eyes with serous and drusenoid PED.

Polarization image segmentation of radiofrequency ablated porcine myocardial tissue.

Optical polarimetry has previously imaged the spatial extent of a typical radiofrequency ablated (RFA) lesion in myocardial tissue, exhibiting significantly lower total depolarization at the necrotic core compared to healthy tissue, and intermediate values at the RFA rim region. Here, total depolarization in ablated myocardium was used to segment the total depolarization image into three (core, rim and healthy) zones. A local fuzzy thresholding algorithm was used for this multi-region segmentation, and then compared with a ground truth segmentation obtained from manual demarcation of RFA core and rim regions on the histopathology image. Quantitative comparison of the algorithm segmentation results was performed with evaluation metrics such as dice similarity coefficient (DSC = 0.78 ± 0.02 and 0.80 ± 0.02), sensitivity (Sn = 0.83 ± 0.10 and 0.91 ± 0.08), specificity (Sp = 0.76 ± 0.17 and 0.72 ± 0.17) and accuracy (Acc = 0.81 ± 0.09 and 0.71 ± 0.10) for RFA core and rim regions, respectively. This automatic segmentation of parametric depolarization images suggests a novel application of optical polarimetry, namely its use in objective RFA image quantification.

Polarimetry based partial least square classification of ex vivo healthy and basal cell carcinoma human skin tissues.

Optical polarimetry was employed for assessment of ex vivo healthy and basal cell carcinoma (BCC) tissue samples from human skin. Polarimetric analyses revealed that depolarization and retardance for healthy tissue group were significantly higher (p<0.001) compared to BCC tissue group. Histopathology indicated that these differences partially arise from BCC-related characteristic changes in tissue morphology. Wilks lambda statistics demonstrated the potential of all investigated polarimetric properties for computer assisted classification of the two tissue groups. Based on differences in polarimetric properties, partial least square (PLS) regression classified the samples with 100% accuracy, sensitivity and specificity. These findings indicate that optical polarimetry together with PLS statistics hold promise for automated pathology classification.

Correlations Between the Individual Risk for Glaucoma and RNFL and Optic Disc Morphometrical Evaluations in Ocular Hypertensive Patients.

PURPOSE: To assess the correlation between the 5-year risk of developing primary open-angle glaucoma (POAG) [on the basis of the Ocular Hypertension Treatment Study (OHTS)-European Glaucoma Prevention Study (EGPS) model] and optic nerve head and retinal nerve fiber layer (RNFL) indices as evaluated by optical coherence tomography (Stratus OCT), scanning laser polarimetry (GDx ECC), and confocal laser ophthalmoscopy [Heidelberg Retinal Tomograph (HRT) III] in ocular hypertensive (OHT) individuals. PARTICIPANTS AND METHODS: Sixty-eight OHT individuals with the untreated intraocular pressure in both eyes between 22 and 32 mm Hg, an ophthalmoscopically normal optic disc with a cup/disc ratio asymmetry between the 2 eyes of ≤0.2, and a visual field with glaucoma hemifield test within normal limits, and pattern SD within P<0.05 were recruited. A comprehensive glaucoma workup and examination by means of OCT, GDx ECC, and HRT III were performed in all of the patients. The probability of developing POAG in 5 years was calculated by means of the OHTS-EGPS model (risk calculator score-RS), which has been developed by the OHTS-EGPS Collaborative Study Group by taking into account the age and the mean values of the central corneal thickness, the intraocular pressure, the pattern SD, and the cup/disc ratio collected in the 2 eyes. Correlations between the individual RS and OCT, GDx, and HRT parameters were then assessed by regression analysis (exponential and linear), with a statistically significant level of P<0.01. RESULTS: The RS of the 68 individuals ranged between 1.5% and 28.6%, with a mean of 10.2% (SD 6.4). Only OCT RNFL-related parameters showed a statistically significant correlation with the RS. The average RNFL thickness had an exponential regression r of 0.21 (P<0.0001) and a linear regression r of 0.14 (P=0.0012); the superior average RNFL thickness had an exponential regression r of 0.26 (P<0.0001) and a linear regression r of 0.23 (P<0.0001); the nasal average RNFL thickness had an exponential regression r of only 0.12 (P=0.0031). Neither GDx RNFL-related parameters nor HRT disc-related parameters showed statistically significant correlations with the RC score. CONCLUSIONS: This explorative study showed that the individual risk to develop POAG within 5 years in OHT individuals is significantly correlated with OCT RNFL parameters, but not with GDx RNFL parameters or HRT disc parameters. OCT parameters could explain about 20% to 25% of the variability in individual RS. The RS seems to take into account the subclinical RNFL thinning shown by the OCT.

Diagnostic Abilities of Variable and Enhanced Corneal Compensation Algorithms of GDx in Different Severities of Glaucoma.

PURPOSE: To compare the abilities of retinal nerve fiber layer (RNFL) parameters of variable corneal compensation (VCC) and enhanced corneal compensation (ECC) algorithms of scanning laser polarimetry (GDx) in detecting various severities of glaucoma. METHODS: Two hundred and eighty-five eyes of 194 subjects from the Longitudinal Glaucoma Evaluation Study who underwent GDx VCC and ECC imaging were evaluated. Abilities of RNFL parameters of GDx VCC and ECC to diagnose glaucoma were compared using area under receiver operating characteristic curves (AUC), sensitivities at fixed specificities, and likelihood ratios. RESULTS: After excluding 5 eyes that failed to satisfy manufacturer-recommended quality parameters with ECC and 68 with VCC, 56 eyes of 41 normal subjects and 161 eyes of 121 glaucoma patients [36 eyes with preperimetric glaucoma, 52 eyes with early (MD>-6 dB), 34 with moderate (MD between -6 and -12 dB), and 39 with severe glaucoma (MD<-12 dB)] were included for the analysis. Inferior RNFL, average RNFL, and nerve fiber indicator parameters showed the best AUCs and sensitivities both with GDx VCC and ECC in diagnosing all severities of glaucoma. AUCs and sensitivities of all RNFL parameters were comparable between the VCC and ECC algorithms (P>0.20 for all comparisons). Likelihood ratios associated with the diagnostic categorization of RNFL parameters were comparable between the VCC and ECC algorithms. CONCLUSION: In scans satisfying the manufacturer-recommended quality parameters, which were significantly greater with ECC than VCC algorithm, diagnostic abilities of GDx ECC and VCC in glaucoma were similar.

Características morfológicas del nervio óptico evaluadas por el tomógrafo láser confocal (HRT3) y polarimetría láser (GDx-VCC) en población normal en la ciudad de Barcelona / Morphological characteristics of the optic nerve evaluated by confocal laser tomography (HRT3) and laser polarimetry (GDx-VCC) in a normal population from the city of Barcelona

OBJETIVO: Evaluar parámetros morfológicos de papila y capa de fibras nerviosas de la retina (CFNR) explorados con el HRT3 y el GDx-VCC en población normal y analizar correlaciones con variables demográficas. PACIENTES Y MÉTODOS: Estudio observacional transversal en el contexto de una campaña de detección de glaucoma en un centro de atención primaria de Barcelona. Se seleccionaron sujetos caucásicos de ascendencia mediterránea, no hipertensos y con riesgo de glaucoma (≥ 60 años o ≥ 40 años con alguno de los siguientes factores de riesgo: antecedentes familiares de glaucoma o de presión intraocular alta o miopía > 3 dioptrías). Se realizó exploración oftalmológica completa incluyendo tomografía láser confocal (HRT3) y polarimetría láser de barrido (GDX-VCC). Todos los sujetos incluidos presentan las pruebas dentro de la normalidad. Se analizaron parámetros estructurales con edad, refracción y paquimetría mediante el test de Spearman. RESULTADOS: Doscientos veinticuatro sujetos incluidos con una media de edad de 63,4 ± 11,1 años. Áreas de disco, excavación y anillo de 2,14 ± 0,52 mm2; 0,44 ± 0,34 mm2 y 1,69 ± 0,38 mm2, respectivamente. Valor medio de la CFNR (GDX) 55,9 ± 6,9 μm. La edad se correlacionó con menor volumen del anillo, mayor índice de morfología de la excavación, mayor profundidad media y máxima de la excavación y menor índice de fibras nerviosas y CFNR (p < 0,05). CONCLUSIÓN: Se proporcionan valores medios y distribución de numerosos parámetros de la papila y la CFNR en población caucásica normal de ascendencia mediterránea. Se observó una pérdida de espesor de la CFNR, adelgazamiento del anillo y aumento de la excavación con la edad

OBJECTIVE: To evaluate morphological parameters of optic disc and retinal nerve fiber layer (RNFL) examined with confocal laser tomography (HRT3) and laser polarimetry (GDx-VCC) in a normal population, and analyze correlations of these parameters with demographic variables. PATIENTS AND METHODS: Cross-sectional study in the context of a glaucoma screening campaign in the primary care center of Barcelona. The individuals selected were non-hypertensive Mediterranean Caucasians with risk for glaucoma development (individuals ≥ 60 years old or ≥ 40 years old with family history of glaucoma or intraocular pressure or myopia > 3 diopter). All subjects underwent a complete ophthalmic examination, confocal laser tomography (HRT3) and scanning laser polarimetry (GDX-VCC), subjects with results within normal limits only being included. Structural parameters were analyzed along with age, refraction, and pachymetry based on the Spearman rank correlation test. RESULTS: A total of 224 subjects included, with a mean age of 63.4 ± 11.1 years. Disc areas, excavation and ring area were 2.14 ± 0.52 mm2, 0.44 ± 0.34 mm 2 and 1.69 ± 0.38 mm2, respectively. The mean RNFL (GDX) was 55.9 ± 6.9 μm. Age was correlated with lower ring volume, highest rate of cup shape measure, largest mean and maximum cup depth, lower nerve fiber index (NFI) and RNFL (all p-values below .05). CONCLUSION: The mean values and distribution of several parameters of the papilla and the RNFL in normal Mediterranean Caucasians population are presented. A loss of thickness of the RNFL, ring thinning, and enlarged cup was observed with increased age

Repeatability and Reproducibility of Retinal Nerve Fiber Layer Parameters Measured by Scanning Laser Polarimetry with Enhanced Corneal Compensation in Normal and Glaucomatous Eyes.

OBJECTIVE: To assess the intrasession repeatability and intersession reproducibility of peripapillary retinal nerve fiber layer (RNFL) thickness parameters measured by scanning laser polarimetry (SLP) with enhanced corneal compensation (ECC) in healthy and glaucomatous eyes. METHODS: One randomly selected eye of 82 healthy individuals and 60 glaucoma subjects was evaluated. Three scans were acquired during the first visit to evaluate intravisit repeatability. A different operator obtained two additional scans within 2 months after the first session to determine intervisit reproducibility. The intraclass correlation coefficient (ICC), coefficient of variation (COV), and test-retest variability (TRT) were calculated for all SLP parameters in both groups. RESULTS: ICCs ranged from 0.920 to 0.982 for intravisit measurements and from 0.910 to 0.978 for intervisit measurements. The temporal-superior-nasal-inferior-temporal (TSNIT) average was the highest (0.967 and 0.946) in normal eyes, while nerve fiber indicator (NFI; 0.982) and inferior average (0.978) yielded the best ICC in glaucomatous eyes for intravisit and intervisit measurements, respectively. All COVs were under 10% in both groups, except NFI. TSNIT average had the lowest COV (2.43%) in either type of measurement. Intervisit TRT ranged from 6.48 to 12.84. CONCLUSIONS: The reproducibility of peripapillary RNFL measurements obtained with SLP-ECC was excellent, indicating that SLP-ECC is sufficiently accurate for monitoring glaucoma progression.

Scanning laser polarimetry and spectral domain optical coherence tomography for the detection of retinal changes in Parkinson's disease.

PURPOSE: Whether retinal degeneration is part of the degenerative processes in patients with Parkinson's disease (PD) is still unclear. This cross-sectional study was undertaken to compare the retinal morphology of patients with PD and healthy controls using spectral domain optical coherence tomography (SD-OCT) and scanning laser polarimetry (SLP). METHODS: Both eyes of patients with PD (n = 108) and healthy controls (n = 165) were examined using SD-OCT and SLP on the same day. Data on the thickness of the retinal nerve fibre layer (RNFL) of all quadrants and the macular area were acquired by OCT (Cirrus, Zeiss). The SLP device (Glaucoma diagnostics (GDx), Zeiss) measured the RNFL and calculated the nerve fibre index (NFI). All patients and probands were checked for concomitant ocular disorders by an ophthalmologist. Visual acuity, intraocular pressure (IOP), objective refraction and the anterior and posterior segment were assessed. RESULTS: Patients with PD showed a reduced macular volume and a reduced central subfield thickness in OCT examinations. The RNFL in the different quadrants did not differ significantly from that of controls. SLP data showed a reduced average RNFL thickness, a decreased thickness of the inferior quadrant and an increase of the NFI in patients with PD. CONCLUSION: PD may be associated with reduced thickness and volume of the macula and a reduced thickness of the RNFL in the inferior quadrant of the retina. Investigations using SD-OCT and SLP revealed distinct but significant differences between patients with PD and healthy controls.

Confocal scan laser ophthalmoscope for diagnosing glaucoma: a systematic review and meta-analysis.

This systematic review was performed to estimate the diagnostic accuracy of the confocal scanning laser ophthalmoscopy in diagnosing glaucoma. We did a sensitive electronic search to find relevant studies. Two reviewers independently screened relevant articles and extracted required data about study methods and reported results of sensitivity and specificity. A meta-analysis was conducted for pooling data to compare different editions of the Heidelberg Retina Tomograph (HRT) with one of its alternatives, scanning laser polarimetry (GDx) with the criteria of "visual field defect" and "changes of nerve fiber layer" as the reference standard. We identified 37 evaluations from 28 relevant primary studies. In these studies, 9573 eyes (4883 glaucomatous and 4689 non-glaucomatous) were assessed with regards to the reference standard using one of the HRT editions with or without GDx. Diagnostic odds ratios were 9.35 [95% confidence interval (CI): 7.58-11.53] for HRT, 11.84 (95% CI: 9.97-14.06) for HRT II, 11.86 (95% CI: 9.16-15.35) for HRT III, and 21.33 (95% CI, 13.56-33.55) for GDx. Although GDx was more accurate than HRT, all editions of HRT had acceptable performance in diagnosing glaucomatous eyes with an ophthalmologist's clinical examination as the reference standard.

[Sensitivity and Specificity of the Nerve Fibre Imaging Using Scanning Laser Ophthalmoscopy and of Optic Nerve Analysis Using Heidelberg Retina Tomography in Glaucoma]. / Sensitivität und Spezifität der Nervenfaserdarstellung mittels Scanning-Laser-Ophthalmoskop und der quantitativen Sehnervenanalyse bei Glaukom.

PURPOSE: Imaging of the optic nerve head and the nerve fibre layer are used in the diagnosis of glaucoma. We have investigated the diagnostic precision of nerve fibre layer imaging using a manually operated scanning laser ophthalmoscope and analysis of the optic nerve head using the Heidelberg Retina Tomograph II (HRT). PATIENTS AND METHODS: 42 patients with glaucoma, 16 patients with ocular hypertension (OHT) and 24 healthy control subjects were included in a clinical study. Nerve fibre layer imaging was performed using a scanning laser ophthalmoscope (SLO, Rodenstock Instr. argon laser 488 nm). Nerve fibre layer defects were analysed peripapillarily for every single degree (defect or no defect) at 1.7 mm (near) and at 3.4 mm (far) distance to the optic nerve head. Specificity and sensitivity of the HRT II were calculated using the Moorfields regression analysis (MRA). RESULTS: Patients with glaucoma were found to have 109 ± 92° (near) and 109 ± 92° (far) defects of the nerve fibre layer. Patients with OHT (8 ± 14° [far] and 6 ± 11° [near]) and control subjects (0 ± 0° [far] and 0 ± 1° [near]) showed significantly smaller defects (p < 0.0001). Sensitivity at > 90 % specificity for POAG and controls was 85.7 % (far) and 82.9 % (near). Sensitivity at > 90 % specifity for OHT and POAG was 85.7 % (far) und 82.9 % (near). Specificity of controls for the MRA was 83.3 % (borderline classified as normal). Specificity of OHT patients was 93.8 % (borderline classified normal). Sensitivity of the MRA for POAG was 80.9 % (borderline classified normal) and 90.5 % (borderline classified glaucoma). CONCLUSIONS: Nerve fiber layer imaging using a manually operated scanning laser ophthalmoscope was found to achieve a higher diagnostic precision as compared to optic disc evaluation using the HRT II.

Atypical birefringence pattern and the diagnostic ability of scanning laser polarimetry with enhanced corneal compensation in glaucoma.

PURPOSE: To evaluate the effect of typical scan score (TSS), when within the acceptable limits, on the diagnostic performance of retinal nerve fibre layer (RNFL) parameters with the enhanced corneal compensation (ECC) protocol of scanning laser polarimetry (SLP) in glaucoma. METHODS: In a cross-sectional study, 203 eyes of 160 glaucoma patients and 140 eyes of 104 control subjects underwent RNFL imaging with the ECC protocol of SLP. TSS was used to quantify atypical birefringence pattern (ABP) images. Influence of TSS on the diagnostic ability of SLP parameters was evaluated by receiver operating characteristic (ROC) regression models after adjusting for the effect of disease severity [based on mean deviation (MD)] on standard automated perimetry). RESULTS: Diagnostic abilities of all RNFL parameters of SLP increased when the TSS values were higher. This effect was statistically significant for TSNIT (coefficient: 0.08, p<0.001) and inferior average parameters (coefficient: 0.06, p=0.002) but not for nerve fibre indicator (NFI, coefficient: 0.03, p=0.21). In early glaucoma (MD of -5 dB), predicted area under ROC curve (AUC) for TSNIT average parameter improved from 0.642 at a TSS of 90 to 0.845 at a TSS of 100. In advanced glaucoma (MD of -15 dB), AUC for TSNIT average improved from 0.832 at a TSS of 90 to 0.947 at 100. CONCLUSION: Diagnostic performances of TSNIT and inferior average RNFL parameters with ECC protocol of SLP were significantly influenced by TSS even when the TSS values were within the acceptable limits. Diagnostic ability of NFI was unaffected by TSS values.

Peripapillary retinal nerve fiber layer assessment of spectral domain optical coherence tomography and scanning laser polarimetry to diagnose preperimetric glaucoma.

PURPOSE: To compare the abilities of peripapillary retinal nerve fiber layer (RNFL) parameters of spectral domain optical coherence tomograph (SDOCT) and scanning laser polarimeter (GDx enhanced corneal compensation; ECC) in detecting preperimetric glaucoma. METHODS: In a cross-sectional study, 35 preperimetric glaucoma eyes (32 subjects) and 94 control eyes (74 subjects) underwent digital optic disc photography and RNFL imaging with SDOCT and GDx ECC. Ability of RNFL parameters of SDOCT and GDx ECC to discriminate preperimetric glaucoma eyes from control eyes was compared using area under receiver operating characteristic curves (AUC), sensitivities at fixed specificities and likelihood ratios (LR). RESULTS: AUC of the global average RNFL thickness of SDOCT (0.786) was significantly greater (p<0.001) than that of GDx ECC (0.627). Sensitivities at 95% specificity of the corresponding parameters were 20% and 8.6% respectively. AUCs of the inferior, superior and temporal quadrant RNFL thickness parameters of SDOCT were also significantly (p<0.05) greater than the respective RNFL parameters of GDx ECC. LRs of outside normal limits category of SDOCT parameters ranged between 3.3 and 4.0 while the same of GDx ECC parameters ranged between 1.2 and 2.1. LRs of within normal limits category of SDOCT parameters ranged between 0.4 and 0.7 while the same of GDx ECC parameters ranged between 0.7 and 1.0. CONCLUSIONS: Abilities of the RNFL parameters of SDOCT and GDx ECC to diagnose preperimetric glaucoma were only moderate. Diagnostic abilities of the RNFL parameters of SDOCT were significantly better than that of GDx ECC in preperimetric glaucoma.

Eye movements during saccadic and fixation tasks in patients with homonymous hemianopia.

BACKGROUND: The aim of our study was to quantify ocular motor performance in patients with homonymous hemianopia and in healthy controls during saccadic and fixation tasks and to detect potential spontaneous adaptive mechanisms in the hemianopic patients. METHODS: Eye movements were recorded in 33 hemianopic patients (15 right, 18 left; disease duration, 0.2-29 years) and 14 healthy subjects by scanning laser ophthalmoscope allowing determination of the absolute fovea position relative to the stimulus without calibration. Landing accuracy of saccades was determined for 5° saccades, indicated by the number of dysmetric saccades (DS), and fixation stability (FS) after landing. In addition, during continuous fixation of a central cross, FS, and distribution of fixational eye movements (FEMs) were measured. Size of macular sparing was determined using custom microperimetry software (stimulus grid, 0.5°). RESULTS: Compared with controls, landing accuracy was decreased in hemianopic patients, indicated by significantly more DS (hypometric and hypermetric) to the blind side compared with the seeing side. The number of DS was greater in patients with macular sparing of <4°. DS were not correlated with age and disease duration. FS after landing was lower after saccades to the blind side. Distribution of FEM during continuous fixation was asymmetrically shifted to the blind side, especially in cases of macular sparing of <4°. CONCLUSIONS: Number of DS was not correlated with disease duration indicating insufficient spontaneous long-term adaptation. Increased number of DS and decreased FS after landing in patients with small or absent macular sparing stresses the importance of intact parafoveal vision. Asymmetric FEMs during continuous fixation indicate an advantageous adaptive mechanism to shift the visual field border towards the hemianopic side.

Retinal nerve fiber layer evaluation of spectral domain optical coherence tomograph and scanning laser polarimeter to diagnose glaucoma.

PURPOSE: To compare the abilities of retinal nerve fiber layer (RNFL) parameters of spectral domain optical coherence tomograph (SDOCT) and scanning laser polarimeter (GDx enhanced corneal compensation; ECC) in detecting glaucoma. METHODS: In a cross-sectional study, 215 eyes of 165 subjects (106 eyes of 79 glaucoma patients and 109 eyes of 86 controls) referred by general ophthalmologists for glaucoma evaluation underwent RNFL imaging with SDOCT and GDx ECC. Ability of RNFL parameters of SDOCT to discriminate glaucoma eyes from control eyes was compared with that of GDx ECC using area under operating characteristic curves (AUCs), sensitivities at fixed specificities, and likelihood ratios (LRs). RESULTS: AUC of the average RNFL thickness of SDOCT to differentiate glaucoma from control eyes (0.868) was comparable (P=0.32) to that of GDx ECC (0.855). Sensitivity at 95% specificity was 63.2% for average RNFL thickness of SDOCT and 48.1% for the average RNFL measurement of GDx ECC. LRs of outside normal limits category of SDOCT parameters ranged between 5.6 and 7.7 while the same of GDx ECC parameters ranged between 3.1 and 3.7. LRs of within normal limits category of SDOCT parameters ranged between 0.18 and 0.24 while the same of GDx ECC parameters ranged between 0.20 and 0.32. CONCLUSION: Though AUCs and sensitivities at fixed specificities were comparable between the RNFL parameters of SDOCT and GDx ECC in diagnosing glaucoma, LRs indicated that the RNFL parameters of SDOCT were better in 'ruling in' glaucoma.

Structure-function relationship between the octopus perimeter cluster mean sensitivity and sector retinal nerve fiber layer thickness measured with the RTVue optical coherence tomography and scanning laser polarimetry.

PURPOSE: To determine structure-function relationship between each of 16 Octopus perimeter G2 program clusters and the corresponding 16 peripapillary sector retinal nerve fiber layer thickness (RNFLT) values measured with the RTVue-100 Fourier-domain optical coherence tomography (RTVue OCT) and scanning laser polarimetry with variable corneal compensation (GDx-VCC) and enhanced corneal compensation (GDx-ECC) corneal compensation. METHODS: One eye of 110 white patients (15 healthy, 20 ocular hypertensive, and 75 glaucoma eyes) were investigated. The Akaike information criterion and the F test were used to identify the best fitting model. RESULTS: Parabolic relationship with logarithmic cluster mean sensitivity and linear sector RNFLT values provided the best fit. For RTVue OCT, significant (P<0.0001) coefficients of determination (R) were found for all 16 RNFLT sectors. The R values were highest for the temporal, superotemporal, and inferotemporal RNFLT sectors (0.4483 to 0.5186). For GDx-VCC/ECC, significant (P<0.01) parabolic relationship was seen for all but the temporal and nasal RNFLT sectors. The overall highest R value (0.6943) was found for a superotemporal RNFLT sector with GDx-ECC. For some RNFLT sectors, the goodness of fit differed significantly between the imaging methods. Structure-function relationship was similar for the total population and the glaucoma subgroup, whereas no relationship (P>0.05) was found for the control eyes. CONCLUSIONS: Mean sensitivity of the Octopus visual field clusters showed significant parabolic relationship with the corresponding peripapillary RNFLT sectors. The relationship was more general with the RTVue OCT than GDx-VCC or GDx-ECC. The results show that visual field clusters of the Octopus G program can be applied for detailed structure-function research.