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The purpose of the current study was to predict intraocular pressure (IOP) using color fundus photography with a deep learning (DL) model, or, systemic variables with a multivariate linear regression model (MLM), along with least absolute shrinkage and selection operator regression (LASSO), support vector machine (SVM), and Random Forest: (RF). Training dataset included 3883 examinations from 3883 eyes of 1945 subjects and testing dataset 289 examinations from 289 eyes from 146 subjects. With the training dataset, MLM was constructed to predict IOP using 35 systemic variables and 25 blood measurements. A DL model was developed to predict IOP from color fundus photographs. The prediction accuracy of each model was evaluated through the absolute error and the marginal R-squared (mR 2 ), using the testing dataset. The mean absolute error with MLM was 2.29 mmHg, which was significantly smaller than that with DL (2.70 dB). The mR 2 with MLM was 0.15, whereas that with DL was 0.0066. The mean absolute error (between 2.24 and 2.30 mmHg) and mR 2 (between 0.11 and 0.15) with LASSO, SVM and RF were similar to or poorer than MLM. A DL model to predict IOP using color fundus photography proved far less accurate than MLM using systemic variables.

Background: Optical coherence tomography (OCT) is being used increasingly to evaluate and manage a variety of retinal diseases, but not much is known about the minification of the OCT images in gas-filled eyes. The purpose of this study was to investigate the effect of gas-filled eyes on the size of the OCT images., Methods: This was retrospective case series of 81 consecutive eyes of 79 patients who had macular hole surgery between April 2012 and September 2014. Images of the optic disc were taken with a spectral domain-OCT instrument 2 days after surgery in gas-filled, pseudophakic eyes and from the same eyes but fluid-filled one month after the surgery. The vertical length, horizontal width, and the area of the optic disc were measured in the OCT images., Results: Clear images were obtained from 50 eyes of 49 patients (mean age 66.4 ± 5.9 years). The mean vertical length and mean horizontal width of the optic disc in the gas-filled eyes were about 25 % shorter than that of fluid-filled eyes (vertical, 1213.8 ± 170.5 and 1650.6 ± 195.9 μm, P < 0.01; horizontal, 1169.4 ± 143.1 and 1526.4 ± 219.9 μm, P < 0.01). The mean area of the optic disc was 1.12 ± 0.34 mm(2) in gas-filled eyes which was significantly smaller than that in fluid-filled eyes (1.88 ± 0.37 mm(2)) by 40.4 %., Conclusions: The fundus images of gas-filled eyes are significantly smaller than that in the same fluid-filled eyes. The minification of the OCT images should be considered when analyzing images obtained from gas-filled eyes., Trial Registration Number: UMIN000007517 . Date of registration: 3/21/2012.

Purpose: Ruling out glaucoma in myopic eyes often poses a diagnostic challenge because of atypical optic disc morphology and visual field defects that can mimic glaucoma. We determined whether neuroretinal rim assessment based on Bruch's membrane opening (BMO), rather than conventional optic disc margin (DM)-based assessment or retinal nerve fiber layer (RNFL) thickness, yielded higher diagnostic accuracy in myopic patients with glaucoma., Design: Case-control, cross-sectional study., Participants: Myopic patients with glaucoma (n = 56) and myopic normal controls (n = 74)., Methods: Myopic subjects with refraction error greater than -2 diopters (D) (spherical equivalent) and typical myopic optic disc morphology, with and without glaucoma, were recruited from a glaucoma clinic and a local optometry practice. The final classification of myopic glaucoma or myopic control was based on consensus assessment by 3 clinicians of visual fields and optic disc photographs. Participants underwent imaging with confocal scanning laser tomography for measurement of DM rim area (DM-RA) and with spectral domain optical coherence tomography (SD OCT) for quantification of a BMO-based neuroretinal rim parameter, minimum rim width (BMO-MRW), and RNFL thickness., Main Outcome Measures: Sensitivity of DM-RA, BMO-MRW, and RNFL thickness at a fixed specificity of 90% and partial area under the curves (pAUCs) for global and sectoral parameters for specificities ≥90%., Results: Sensitivities at 90% specificity were 30% for DM-RA and 71% for both BMO-MRW and RNFL thickness. The pAUC was higher for the BMO-MRW compared with DM-RA (P < 0.001), but similar to RNFL thickness (P > 0.5). Sectoral values of BMO-MRW tended to have a higher, but nonsignificant, pAUC across all sectors compared with RNFL thickness., Conclusions: Bruch's membrane opening MRW is more sensitive than DM-RA and similar to RNFL thickness for the identification of glaucoma in myopic eyes and offers a valuable diagnostic tool for patients with glaucoma with myopic optic discs., (Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Ocular torsion can been measured by perimetry, double Maddox rod, Bagolini glasses, indirect ophthalmoscopy lens, slit-lamp biomicroscopy, synoptophore, and fundus photography. Wide variations have been reported in the measurement of the disk foveal angle (DFA) using fundus photography. We describe a technique for measuring the DFA, formed by a horizontal line extending from the center of the optic disk and a line from the center of disk to the fovea, using Microsoft PowerPoint and ImageJ software., (Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine whether confocal scanning laser ophthalmoscopic imaging (Heidelberg retinal tomography [HRT]) can predict visual field change in glaucoma., Methods: The study included 561 patients with glaucoma or ocular hypertension whose clinical course was followed at the Mount Sinai Faculty practice. Humphrey visual fields (HVFs) and HRT images were collected on one randomly selected eye per patient. Glaucoma progression was determined by the presence of two sequential statistically significant negative slopes in mean deviation (MD) or visual field index (VFI) at any point during the study period. Trend-based analysis on HRT parameters was used to determine progressive changes and whether these occurred before or after HVF change. Sensitivity and specificity of HRT to predict HVF change were calculated. HVF rate of change was correlated to the rate of change detected by HRT imaging., Results: Approximately 17% of patients progressed by either MD or VFI criteria. MD and VFI correlated highly and identified overlapping sets of patients as progressing. HRT global parameters had poor sensitivity (∼42%) and moderate specificity (∼67%) to predict HVF progression. Regional stereometric parameters were more sensitive (69%-78%) but significantly less specific (24%-27%). Sensitivity of global stereometric parameters in detecting HVF change was not significantly affected by the level of visual field damage (P=.3, Fisher exact test). HVF rate of change did not correlate with rate of change of HRT parameters., Conclusions: Trend-based analysis of HRT parameters has poor sensitivity and specificity in predicting HVF change. This may be related specifically to HRT imaging or may reflect the fact that in some patients with glaucoma, functional changes precede structural alterations.

Purpose: To evaluate the effect of scan quality on the diagnostic accuracies of optic nerve head (ONH), retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) parameters of spectral-domain optical coherence tomography (SD OCT) in glaucoma., Design: Cross-sectional study., Methods: Two hundred fifty-two eyes of 183 control subjects (mean deviation [MD]: -1.84 dB) and 207 eyes of 159 glaucoma patients (MD: -7.31 dB) underwent ONH, RNFL, and GCC scanning with SD OCT. Scan quality of SD OCT images was based on signal strength index (SSI) values. Influence of SSI on diagnostic accuracy of SD OCT was evaluated by receiver operating characteristic (ROC) regression., Results: Diagnostic accuracies of all SD OCT parameters were better when the SSI values were higher. This effect was statistically significant (P < .05) for ONH and RNFL but not for GCC parameters. In mild glaucoma (MD of -5 dB), area under ROC curve (AUC) for rim area, average RNFL thickness, and average GCC thickness parameters improved from 0.651, 0.678, and 0.726, respectively, at an SSI value of 30 to 0.873, 0.962, and 0.886, respectively, at an SSI of 70. AUCs of the same parameters in advanced glaucoma (MD of -15 dB) improved from 0.747, 0.890, and 0.873, respectively, at an SSI value of 30 to 0.922, 0.994, and 0.959, respectively, at an SSI of 70., Conclusion: Diagnostic accuracies of SD OCT parameters in glaucoma were significantly influenced by the scan quality even when the SSI values were within the manufacturer-recommended limits. These results should be considered while interpreting the SD OCT scans for glaucoma., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Purpose: The purpose of this study was to determine whether exercise affects the stereometric parameters representing optic nerve head (ONH) topography., Methods: ONH topography, intraocular pressure (IOP) and blood pressure of 30 healthy volunteers were monitored before, during and after dynamic exercise raising systolic blood pressure by a minimum of 30 mmHg. Change in the stereometric ONH parameters was calculated., Results: IOP decreased and blood pressure increased during exercise, resulting in an increase in mean ocular perfusion pressure. Exercise was associated with an increase in variance in 17 of the 18 stereometric ONH parameters. The increase in variance was statistically significant in eight parameters, including rim area, cup/disc area ratio and cup shape measure. There was no statistically significant change in image quality. The absolute change from baseline in rim area, cup area, cup/disc area ratio, rim/disc area ratio and rim volume showed a statistically significant (p < 0.05) correlation with change in mean ocular perfusion pressure., Conclusions: Exercise increases variability in stereometric ONH parameters. To avoid increased variance in the stereometric parameters, ONH imaging should be performed after allowing sufficient time to rest., (© 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.)

Purpose: To evaluate the longitudinal reproducibility of optical coherence tomography (OCT) measurements in normal and glaucomatous eyes of children., Methods: In this 2-setting prospective study, OCT-3 was used to obtain fast retinal nerve fiber layer (RNFL) and macular thickness scans. In the first study setting, the normal eyes of healthy children were scanned on presentation, at 2 weeks, and 3 years, with axial length measured at the first and last examinations. In the second setting, OCT scans of patients in the pediatric glaucoma clinic were performed over 4 years as clinically indicated. Eyes were classified as "normal" (normal eyes and those with physiologic cupping but normal intraocular pressure [IOP]); "mild glaucoma" (increased IOP and a normal optic nerve appearance); or "advanced glaucoma" (severe cupping or progressive glaucoma). Intraclass correlation coefficients were used to evaluate the reproducibility of measurements on the same day and over time., Results: In the first setting, 8 normal eyes were included. Axial length increased 0.11 ± 0.04 mm/year over an average of 3.3 years (P = 0.03); there was no statistically significant change in RNFL thickness (P = 0.30). In our second setting, 27 normal eyes and 37 eyes with glaucoma were included. Intraclass correlation coefficients across the 3 visits for total macular volume were 0.80-0.91 and for average RNFL were 0.73-0.95., Conclusions: Global OCT measurements in children were reproducible over years and were not affected by normal increase in axial length. OCT shows promise as an objective tool for longitudinal assessment of children., (Copyright © 2012 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.)

Objective: To evaluate the agreement of optic disc measurements obtained with the Cirrus high-density optical coherence tomography (HD-OCT) and the Heidelberg retina tomograph (HRT) and compare the intervisit, test-retest variability between the instruments., Design: Prospective, cross-sectional study., Participants: Two hundred seven subjects (109 glaucoma and 98 normal subjects)., Methods: One eye from each individual was selected randomly for optic disc imaging by the Cirrus HD-OCT and the HRT. Areas of the optic disc and the cup, cup volume, vertical cup-to-disc ratio and cup-to-disc area ratio were compared between the instruments. The OCT measurements were corrected for ocular magnification using the Littman's formula. The measurement agreement was evaluated with the Bland-Altman plots. The intervisit test-retest variability was examined in 17 randomly selected glaucoma patients who underwent optic disc imaging weekly for 8 consecutive weeks. The intraclass correlation coefficients (ICC) and the reproducibility coefficients of the optic disc parameters were computed., Main Outcome Measures: Measurement agreement, reproducibility coefficients, and ICCs of optic disc parameters., Results: The OCT measured smaller optic disc and rim areas and greater cup volume, vertical cup-to-disc ratio and cup-to-disc area ratio than the HRT did (all with P<0.001). There were proportional biases in the Bland-Altman plots between OCT and HRT optic disc measurements except for rim area and cup-to-disc area ratio. The 95% limits of agreement of rim area ranged between -0.28 and 0.88 mm(2) before, and between -0.22 and 0.92 mm(2) after correction for ocular magnification. Both OCT and HRT showed high test-retest reproducibility with ICCs ≥ 0.921. Although the reproducibility coefficient of OCT rim area (0.093 mm(2); 95% confidence interval [CI], 0.081-0.105 mm(2)) was significantly smaller than that of the HRT (0.186 mm(2); 95% CI, 0.163-0.210 mm(2); P = .018), there were no differences in the ICCs between the instruments., Conclusions: Optic disc assessment by spectral-domain OCT and confocal scanning laser ophthalmoscopy demonstrates poor agreement but similarly low test-retest variability. The source of their disagreement and its effects on the detection of progression require further study., (Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess inter-device measurement variability with the Stratus optical coherence tomography (OCT)., Design: Evaluation of diagnostic test technology., Methods: Eight eyes of eight healthy subjects were examined with four different Stratus machines in four medical centers during a period of five hours using fast retinal nerve fiber layer (RNFL) and fast macula protocols. Inter-device measurement variability and signal strength was assessed with standard deviation, coefficient of variance, and intraclass correlation coefficient (ICC). Spearman correlation coefficient was calculated between signal strength and thickness measurements., Results: Statistically significant differences were not found for all macular parameters and all but one RNFL parameter. Mean signal strengths obtained with the four Stratus machines were significantly different; the newer the machine, the stronger signal strength it produced. Some RNFL parameters were moderately and statistically significantly correlated with signal strength., Conclusions: We did not observe statistically significant differences in any macular and all but one RNFL parameter between the four Stratus OCT machines. Signal strength was significantly different between the machines, and significantly correlated with some RNFL parameters. Inter-machine variability in RNFL measurements may have clinical significance. Signal strength should be included in the assessment of measurements obtained on different machines and in serial examinations with a single Stratus machine during patient follow-up.

Background: Scattering of blood flow data as assessed with laser Doppler flowmetry (LDF) in humans is a problem in many studies using this technique. We set out to reduce variability in LDF data by eliminating the effect of the total returning light level (DC) on LDF parameters in the choroid through partial regression analysis., Methods: In 20 healthy subjects, choroidal blood flow parameters were measured at different DC values using a portable confocal LDF device. We used two different strategies to reduce scattering of data eliminating the effect of yield, which is defined as DC/gain. On the one hand, we used a previously described method based on a third-order polynomial fit, which combines all obtained data. On the other hand, we applied a new method based on a linear fit for each individual subject., Results: Variability of data during changes in DC is higher for LDF parameters volume and flow than for velocity. Both methods were successful in reducing scattering of LDF parameters with varying DC., Conclusions: The present study indicates that both methods to correct for changes in yield were successful in reducing the variability of LDF measurements. When systematic changes in DC occur after an intervention, one needs to be careful in interpreting the obtained data and it remains to be shown if either of the two techniques is capable of correcting for this effect. The approach presented here may, however, represent an effective, easily applicable and valid approach to reduce scattering of data from using LDF to assess blood flow in the posterior pole of the human eye.

Purpose: To determine the reproducibility of optical coherence tomography (OCT) measurements of macular thickness, peripapillary nerve fiber layer (NFL) thickness, and optic disk parameters and to investigate the effect of axial length and refractive error on these measurements in children with healthy eyes., Design: Cross-sectional study., Methods: The Sydney Childhood Eye Study examined 2,353 year 7 students (75.3% response) from a random cluster sample of 21 secondary schools across Sydney. A consecutive subsample of 120 children had OCT (StratusOCT, Carl Zeiss, Dublin, California, USA) performed by a single operator, which was repeated with a brief rest between the two sessions. Scans of the NFL, macula, and optic disk were performed., Results: Intersubject variability of measurements of macular thickness, NFL thickness, and optic disk parameters assessed using intraclass correlation coefficients accounted for >85%, >62%, and >38% of total variability of measurements, respectively. Corresponding coefficients of variability were <5%, <8%, and <13%. Magnification effects attributable to axial length and refractive error on the measurement of these parameters were statistically not significant., Conclusion: The StratusOCT demonstrated reproducible measurements of macular and NFL thickness. Measurement of most optic disk parameters were also reproducible. Magnification attributable to axial length and refractive error had minimal impact on measurements of macular and NFL thickness.

Objective: To evaluate the results of scanning laser tomography and scanning laser polarimetry (SLP) and the correlations with visual field damage (VFD) in eyes with nonarteritic ischemic optic neuropathy (n-AION) compared with eyes with open-angle glaucoma (OAG)., Design: Cross-sectional study., Participants: Thirty-three eyes of 33 patients with n-AION and 33 eyes with OAG whose age and VFD evaluated with the Humphrey field analyzer were matched to those of the n-AION eyes., Main Outcome Measures: The parameters of optic disc topography obtained with the Heidelberg Retina Tomograph II (HRT II) and retinal nerve fiber layer (RNFL) thickness with GDx with variable corneal compensation and the correlation to VFD., Results: The cup area, cup-to-disc area ratio, and mean cup depth were significantly smaller, and the cup shape measure more negative, in the n-AION eyes than in the OAG eyes (P<0.001), whereas rim area was significantly greater (P<0.001). Multivariate analyses showed that none of disc area, rim area, and mean cup depth in the n-AION eyes and only rim area (P = 0.029) in the OAG eyes was significantly associated with mean deviation (MD). Ellipse average of RNFL thickness significantly correlated with MD in the n-AION eyes (P = 0.045) and in the OAG eyes (P = 0.022)., Conclusions: Disc topography of eyes with n-AION was quantitatively characterized by small and shallow cupping and a relatively large rim area compared to eyes with OAG matched for age and VFD. In eyes with n-AION, significant correlation with VFD was found only for the RNFL thickness evaluated with SLP but not for the HRT II parameters.

Purpose: To compare the level of agreement between subjective and objective methods in estimating horizontal and vertical cup-to-disc ratios (HCDR and VCDR, respectively) to determine if objective techniques may be used as surrogates for subjective cup-to-disc (CDR) estimation., Methods: Fifty-one glaucoma patients and 49 control subjects underwent full ophthalmic examination, stereoscopic optic nerve head photographs (ONHPs), confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomography II [HRT II]), and optical coherence tomography (Stratus OCT). The intraclass correlation coefficient (ICC) and Bland Altman plots were used to assess the agreement across the three methods. Repeated measures analysis of variance (ANOVA), Tukey adjustment, and pairwise P values were used to compare the HCDR and VCDR estimates between three clinicians who reviewed photos, Stratus OCT, and HRT II., Results: For the clinicians, the agreement in subjectively assessed HCDR and VCDR was substantial (ICC=0.84 and 0.85, respectively), and for all three methods, overall agreement was good (ICC=0.75 and 0.77 for the HCDR and VCDR, respectively). Stratus OCT provided the largest overall mean+/-SD HCDR (0.68+/-0.14) and VCDR (0.62+/-0.13). The smallest overall mean+/-SD HCDR was provided by ONHP (0.32+/-0.16), and the smallest overall mean+/-SD VCDR was provided by HRT II (0.26+/-0.20). Repeated measures ANOVA test demonstrated significant differences across the three methods for glaucomatous (P=0.0017 and 0.0016, HCDR and VCDR, respectively) and normal (P=0.0001 for both HCDR and VCDR) eyes. Tukey adjustment demonstrated specific statistical differences between pairs of methods., Conclusions: Although the overall agreement between various methods was good, the mean estimates were statistically different. Additional studies are needed to evaluate the sources of variability, their level of significance, and longitudinal agreement between various methods of the CDR estimation.

Purpose: Optical coherence tomography may be a new technique for quantitative 3-dimensional assessment of the optic nerve head for diagnosis of optic nerve anomalies and diseases such as the glaucomas. The purpose of the present study was to examine its reproducibility., Patients and Methods: The clinical noninterventional study included 10 randomly chosen eyes of 10 healthy individuals who underwent 24 optical coherence tomographic examinations with the high-resolution and fast scan program, interactively corrected or uncorrected. The pupils were not dilated. All examinations were performed by 3 examiners independently of one another. The coefficient of variation was calculated as the ratio of the mean of the standard deviations divided by the mean of the means., Results: The coefficients of variation for redetermination of optic disc area, ranging between 0.047 and 0.119, were lowest for the manually corrected fast scan mode and highest for the uncorrected fast scan mode. For remeasurements of the neuroretinal rim area, the best mean coefficient of variation was 0.073+/-0.026 (corrected fast scan mode)., Conclusions: In healthy eyes, the morphometric measurements of the optic nerve head by optical coherence tomography show a relatively high reproducibility with mean coefficients of variation lower than 10% for remeasurements of the optic disc and neuroretinal rim area. With undilated pupils, reproducibility is better with the fast scan mode with interactive correction of the outlining of the optic disc border than it is with the high-resolution mode.

Purpose: To determine the test-retest variability in perimetric, optic disc, and macular thickness parameters in a cohort of treated patients with established glaucoma., Patients and Methods: In this cohort study, the authors analyzed the imaging studies and visual field tests at the baseline and 6-month visits of 162 eyes of 162 participant in the Glaucoma Imaging Longitudinal Study (GILS). They assessed the difference, expressed as the standard error of measurement, of Humphrey field analyzer II (HFA) Swedish Interactive Threshold Algorithm fast, Heidelberg retinal tomograph (HRT) II, and retinal thickness analyzer (RTA) parameters between the two visits and assumed that this difference was due to measurement variability, not pathologic change. A statistically significant change was defined as twice the standard error of measurement., Results: In this cohort of treated glaucoma patients, it was found that statistically significant changes were 3.2 dB for mean deviation (MD), 2.2 for pattern standard deviation (PSD), 0.12 for cup shape measure, 0.26 mm for rim area, and 32.8 microm and 31.8 microm for superior and inferior macular thickness, respectively. On the basis of these values, it was estimated that the number of potential progression events detectable in this cohort by the parameters of MD, PSD, cup shape measure, rim area, superior macular thickness, and inferior macular thickness was 7.5, 6.0, 2.3, 5.7, 3.1, and 3.4, respectively., Conclusions: The variability of the measurements of MD, PSD, and rim area, relative to the range of possible values, is less than the variability of cup shape measure or macular thickness measurements. Therefore, the former measurements may be more useful global measurements for assessing progressive glaucoma damage.

Objective: To study the optic nerve head (ONH) parameters and topograph features of normal subjects, and analyze the effect of gender, laterality, age and disc size on the topograph of ONH., Methods: Heidelberg Retina Tomograph (HRT) was used to obtain the optic nerve head parameters and topograph images in 216 eyes of 116 normal volunteers. The impact of gender, laterality, age and disc size on the topograph was analyzed. The optic disc was divided into three groups by their size, small (less than 1.5 mm2), middle and large disc (equal or larger than 2.5 mm2), to evaluate the differences of parameters., Results: The parameters of ONH in normal eyes were as following: disc area (DA) (2.208 +/- 0.411) mm, cup area (CA) (0.466 +/- 0.355) mm2, cup/disk area ratio (C/DAR) (0.217 +/- 0.137), rim area (RA) (1.563 +/- 0.339) mm2, height variation contour (HVC) (0.404 +/- 0.096) mm, cup volume (CV) 0.127 mm3, rim volume (RV) (0.446 +/- 0.173) mm3, mean cup depth (MCD) (0.196 +/- 0.096) mm, maximum cup depth (MxCD) (0.559 +/- 0.228) mm, cup shape measure (CSM) (-0.213 +/- 0.076), mean retinal nerve fiber layer thickness (mRNFLT) (0.272 +/- 0.076) mm, and retinal nerve fiber layer cross section area (RNFLA) (1.364 +/- 0.375) mm2. There were significant differences between right and left eyes in C/DAR, RA and RV, but no difference between different genders in all parameters. A negative correlation was found between mRNFLT, RNFLA and age. There were significant differences in most parameters among three groups with different disc size, such as CA, C/DAR, CV, RA and CSM, but not in mRNFLT, RNFLA and RV., Conclusions: Significant variations were found in parameters of ONH in normal subjects. Some parameters of ONH were affected by age and optic disc size. There were differences in some parameters between right and left eyes, but not between different genders. There were differences of parameters between different quadrants of ONH.

Purpose: The GDx is a scanning laser polarimeter that assesses peripapillary nerve fiber layer thickness. In addition to the 14 existing outcome parameters, four new parameters have been described recently: the Ellipse Standard Deviation (ESD), the Normalized Superior Area (NSA), the Normalized Inferior Area (NIA) and the Discriminant Analysis (DA). The aim of this study was to investigate the sensitivity and specificity of these four new parameters., Methods: Only one randomly selected eye of 263 healthy volunteers and 241 glaucoma patients was considered. The healthy group was randomly divided into a reference set (n = 132) to calculate the tenth percentile of the normal distribution and a test set (n = 131) to calculate the specificity against these newly established cut-off points. Sensitivity was calculated for all glaucoma patients (n = 241) and again for three separate subgroups: early glaucoma (n = 90), moderate glaucoma (n = 93), and advanced glaucoma (n = 58)., Results: When the tenth percentile of the normal distribution was used as a cut-off point, the sensitivity and specificity pairs of the new parameters were 61.8% and 87.6%, 61.8% and 89.1%, 50.2% and 92.2% and 72.6% and 95.3% for the ESD, NSA, NIA, and the DA, respectively. The Area under the ROC curve was 0.86, 0.86, 0.87, and 0.90, respectively. Among the existing parameters, the Number discriminated best (sensitivity and specificity: 76.8% and 89.1%, respectively; area under the ROC curve: 0.90). When compared with The Number, the DA was equally good, whereas the other three new parameters performed statistically significantly worse. In general, the area under the ROC curve increased from early to moderate to advanced glaucoma., Conclusions: The new GDx parameters discriminated well between normal subjects and glaucoma patients. None of the new parameters discriminated better than The Number.

Purpose: To evaluate the clinical agreement in the detection of optic disk changes in patients with glaucoma using simultaneous stereophotographs., Design: Masked-observer variability study., Methods: Ten glaucoma specialists examined pairs of simultaneous stereophotographs of glaucomatous and control optic disks to determine whether there were changes compatible with progression of glaucomatous damage., Results: Intraobserver agreement had a kappa value ranging from 0.55 to 0.78. Interobserver agreement among the glaucoma specialists had a kappa value ranging from 0.34 to 0.68., Conclusions: Clinical examination of stereophotographs to detect optic disk changes in glaucoma patients has limitations associated with suboptimal reproducibility.

Purpose: The Number is a standard parameter of the GDx that reportedly distinguishes normal and glaucomatous eyes. The authors evaluated the sensitivity and specificity of the Number and examined whether expert clinical judgment of GDx printouts leads to a better separation., Materials and Methods: Two experienced observers judged 800 GDx scans on 400 randomly presented printouts from 200 glaucoma patients and 200 age-matched normal subjects. The diagnosis was based on the symmetry analysis printout and was per patient rather than per eye. The observers assessed sensitivity for all glaucoma patients together, and separately for mild, moderate, and severe glaucoma. Their specificity was determined in the group of normal subjects. The same procedure was performed for the Number, at various critical values., Results: Both observers discriminated better than the Number. At a critical value of 23, the specificity of the Number was 81.5%, which matched the lowest specificity of the 2 observers: 82.5% and 92.0% for observers 1 and 2, respectively. At these specificities, the sensitivity of the 2 observers and of the Number were 92.0%, 89.5%, and 85.5%, respectively. The sensitivity increased with the severity of glaucoma. The Kappa values for intraobserver agreement were 0.80 and 1.0., Conclusions: The Number yielded acceptable sensitivity and specificity values at a critical value of 23 in this test population. However, the clinical judgments of the printouts by both expert observers resulted in a better separation between normal and glaucomatous eyes, particularly in the group with mild glaucoma.

Purpose: To determine reasons for rim area variability in scanning laser tomography., Methods: Regional rim area variability from testing in same and different visits and by same and different observers was characterized in 30 normal and 42 glaucomatous eyes. Variations in (1) optic nerve head (ONH) surface geometry (center of gravity: X, Y, Z), (2) image tilting (horizontally and vertically), and (3) position of the reference plane in relation to the ONH (REF) were analyzed by multiple regression analysis. Whether and how much these factors explain rim area variability was studied in cross-sectional and longitudinal data by using two different reference planes., Results: Variability was higher in glaucoma and in testing by different observers in separate visits. Across a range of eyes, approximately 40% of variability in single-topography images and 60% of variability in mean-topography images was explained. In individual image series, a median 85% of variability was explained, exceeding 90% in at least 25% of eyes. The most frequent contributors to rim area variability were REF (in > or =95%) and Z (in > or =80%); they also usually explained more variability than other factors. The nature of variability differed between reference planes., Conclusions: A large proportion of rim area variability was explained by variation in the topographical features studied, especially REF and Z. Reference plane definition also influenced variability. Variation in the position of the reference plane in relation to the ONH can affect rim area measurements and should be considered when evaluating the progression of glaucoma.

Purpose: To describe and evaluate a new experimental reference plane for measuring rim area in scanning laser tomography., Methods: The experimental reference plane was positioned so that (1) it always lay entirely below the margin of the optic nerve head (ONH), (2) it remained at a set z-axis distance below the ONH in images of each eye, and (3) it was at a level where variability in rim area is least. Twenty normal control subjects and 20 patients with glaucoma underwent test-retest scanning laser tomographic imaging by same and different operators during same and separate visits. Control subjects had image series spanning at least 3 years. The effect of the positioning of the reference plane on global and regional rim area variability was assessed in intra- and intervisit test-retest images and longitudinal image series and compared with the standard and 320- microm reference planes., Results: Variability in the experimental reference plane was less in test-retest images and longitudinal data (P < 0.05) and more uniform around the ONH than with other reference planes. Variability in the former was not appreciably affected by testing involving different operators and visits, or by the presence of glaucoma., Conclusions: Variability in rim area by the experimental reference plane was significantly less, more uniform around the ONH, not affected by different operators and visits, and less affected by glaucomatous morphology than other reference planes. This difference was pronounced in sequential data and has implications for detecting progression of glaucoma.

Purpose: To report the reliability of the glaucoma disk damage likelihood scale (DDLS) in comparison to the Armaly cup/disk ratio by determining the interobserver and intraobserver agreement for optic disk stereo photographs and the interobserver agreement for in vivo patient measurements of the optic disk., Design: Observational case series., Methods: Optic disk photographs: 48 stereo pairs of optic nerve photographs were selected from patients with a spectrum of glaucomatous visual field loss. Two masked observers graded the optic disk photographs three times according to the DDLS and Armaly cup/disk ratio. Interobserver and intraobserver agreements were calculated using the test-retest method. Patient measurements: three observers performed in vivo patient measurements on 34 eyes of glaucoma clinic patients and made a single determination of the DDLS stage and Armaly cup/disk ratio, based on the indirect biomicroscopic examination. Level of interobserver agreement was tabulated., Results: Optic disk photographs: interobserver and intraobserver agreement for the vertical DDLS measurement was greater than for two determinations (clinical impression and measured) of the vertical Armaly cup/disk ratio (interobserver: 85% vs 68% and 74%, respectively; intraobserver grader 1: 97% vs 89% and 80%, grader 2: 99% vs 95% and 89%, respectively). In vivo patient measurements: the interobserver agreement for the DDLS and Armaly cup/disk ratio was similar (70.1% vs 67.6%, respectively)., Conclusions: For the stereo optic disk photographs, the inter- and intra-observer agreement for the DDLS is greater than the Armaly cup/disk ratio. For the in vivo patient measurements, the level of agreement for the DDLS and the Armaly cup/disk ratio is similar.

Purpose: To study the test-retest variability of stereometric parameters on the Heidelberg Retina Tomograph II, a new clinical instrument for glaucoma management., Methods: In a cross-sectional study of 24 consecutive cases of glaucoma and 26 healthy subjects, Heidelberg Retina Tomograph II stereometric parameters from five consecutive images were obtained for one randomly selected eye of each subject. Test-retest variability was studied using three different statistical methods (coefficient of variance, intraclass correlation coefficient, and Cronbach alpha). The effect of age, diagnosis, linear cup/disc ratio, visual acuity, and refractive error on test-retest variability on HRT II was analyzed. The repeatability of Moorfields regression analysis and the baseline variability in the progression analysis software was also studied., Results: Using coefficient of variance, intraclass correlation coefficient, and Cronbach alpha, the test-retest variability was found to be lowest for mean cup depth, cup area, cup/disc area ratio, vertical cup/disc ratio and rim/disc area ratio, in that order. Test-retest variability had a significant correlation with age (r = 0.33, P = 0.019) and visual acuity (r = -0.46, P = 0.005). Compared with eyes with astigmatism less than 1 D (mean coefficient of variance = 6.4 +/- 4.9), the test-retest variability was higher (P = 0.044) in eyes with astigmatism more than 1D (mean coefficient of variance = 20.0 +/- 22.6). Moorfields regression analysis was inconsistent in 52% cases. The average baseline change in progression analysis software was 0.076 +/- 0.081., Conclusion: The test-retest variability of Heidelberg Retina Tomograph II stereometric parameters is comparable to that reported for the Heidelberg Retina Tomograph. Eyes with uncorrected astigmatism more than 1 D and poor visual acuity may have a higher variability of Heidelberg Retina Tomograph II stereometric parameters.

Purpose: The Heidelberg Retina Tomograph (HRT) is a confocal scanning laser tomograph that produces high resolution optical section images of the optic disc and central retina. Measurement accuracy and reproducibility is good. Several of the stereometric variables depend on the definition of a reference plane level. The purpose of the present study was to evaluate the four different reference levels in terms of their advantages and disadvantages in clinical work., Methods: Sixty-seven randomly chosen eyes belonging to 67 subjects were included in this study. Forty of the eyes were healthy and 27 had glaucoma. The HRT with software versions 1.09 and 1.11 was used to acquire and evaluate topographic measurements of the optic disc. Image analysis was performed at four different reference levels: 320 microm fixed offset reference level (REFd) (version 1.09), an individually determined reference level (REFi), a papillo-macular reference level (REFm) and a flexible reference level (REFf) (version 1.11). ANOVA was used to determine differences in the topographic parameters between the reference levels., Results: In terms of the healthy eyes, all the variables using different reference levels give rather similar results. However, with advanced glaucoma the measurement values provided with REFd are clearly different to those of the other reference levels. The measurement values using REFm and REFf provide fairly similar results in all clinical groups. REFf indicates the lowest point in the segment between 350 degrees and 356 degrees along the contour line and thus provides the most stable and clinically useful reference level at present., Conclusion: At present, the flexible reference level REFf gives the most reliable and adequate HRT measurement values, both in normal and in glaucomatous eyes.