Accuracy of Diagnostic Imaging Modalities for Classifying Pediatric Eyes as Papilledema Versus Pseudopapilledema.

PURPOSE: To identify the most accurate diagnostic imaging modality for classifying pediatric eyes as papilledema (PE) or pseudopapilledema (PPE). DESIGN: Prospective observational study. SUBJECTS: Nineteen children between the ages of 5 and 18 years were recruited. Five children (10 eyes) with PE, 11 children (19 eyes) with PPE owing to suspected buried optic disc drusen (ODD), and 3 children (6 eyes) with PPE owing to superficial ODD were included. METHODS: All subjects underwent imaging with B-scan ultrasonography, fundus photography, autofluorescence, fluorescein angiography (FA), optical coherence tomography (OCT) of the retinal nerve fiber layer (RNFL), and volumetric OCT scans through the optic nerve head with standard spectral-domain (SD OCT) and enhanced depth imaging (EDI OCT) settings. Images were read by 3 masked neuro-ophthalmologists, and the final image interpretation was based on 2 of 3 reads. Image interpretations were compared with clinical diagnosis to calculate accuracy and misinterpretation rates of each imaging modality. MAIN OUTCOME MEASURES: Accuracy of each imaging technique for classifying eyes as PE or PPE, and misinterpretation rates of each imaging modality for PE and PPE. RESULTS: Fluorescein angiography had the highest accuracy (97%, 34 of 35 eyes, 95% confidence interval 92%-100%) for classifying an eye as PE or PPE. FA of eyes with PE showed leakage of the optic nerve, whereas eyes with suspected buried ODD demonstrated no hyperfluorescence, and eyes with superficial ODD showed nodular staining. Other modalities had substantial likelihood (30%-70%) of misinterpretation of PE as PPE. CONCLUSIONS: The best imaging technique for correctly classifying pediatric eyes as PPE or PE is FA. Other imaging modalities, if used in isolation, are more likely to lead to misinterpretation of PE as PPE, which could potentially result in failure to identify a life-threatening disorder causing elevated intracranial pressure and papilledema.

Photopic negative response of full-field electroretinography in patients with different stages of glaucomatous optic neuropathy.

PURPOSE: To evaluate photopic negative response (PhNR) discrimination ability between healthy and glaucomatous patients. METHODS: Ninety eyes of 50 patients with primary open angle glaucoma (POAG) and 45 eyes of 23 healthy age- and sex-matched controls were investigated. Based on European Glaucoma Society criteria, POAG patients were divided into three groups: early, moderate and advanced glaucoma. Following measurements were analysed: mean defect (MD) from Humphrey Visual Field Analyzer, SITA standard 24-2 white on white perimetry; nerve fibre index (NFI) obtained from scanning laser polarimetry; and GDx and PhNR amplitude and PhNR/b-wave ratio. PhNR was elicited by red stimuli with flash strength of 1.6 cd s/m(2) on blue background of 25 cd/m(2). Correlations between retinal ganglion cells function (PhNR), retinal sensitivity (MD) and structure (NFI) were calculated. Sensitivity and specificity of PhNR parameters were calculated with standard formulas. Receiver operating characteristic (ROC) curves were used to determine optimal cut-off values. The area under the curve (AUC) was used to compare the ROC curves results between PhNR amplitude and ratio. RESULTS: PhNR amplitude and ratio were significantly reduced in early, moderate and advanced glaucoma groups compared to controls. The sensitivity and specificity to detect glaucoma in early POAG were equal to 53.3 and 90.0% for PhNR amplitude and 60.0 and 70.0% for PhNR ratio; in moderate POAG 63.3 and 80.0% for PhNR amplitude and 60.0 and 86.7% for PhNR ratio; and in advanced POAG 76.6 and 80.0% for PhNR amplitude, 90.0 and 73.3% for PhNR ratio. There were no significant differences between AUC for PhNR amplitude (0.76-0.86) and PhNR ratio (0.78-0.86), p > 0.05. PhNR amplitudes and ratios correlated significantly with MD measured by SAP and NFI obtained from GDx (p < 0.05). PhNR amplitude significantly decreases with advancement of visual field defects in glaucoma patients. CONCLUSIONS: PhNR reveals dysfunction of RGCs in early, moderate and advanced stage of POAG. PhNR has good discrimination ability in detecting glaucomatous patients. PhNR might be a useful test in glaucoma diagnosis.

Estimation of the Disc Damage Likelihood Scale in primary open-angle glaucoma: the Glaucoma Stereo Analysis Study.

PURPOSE: The Glaucoma Stereo Analysis Study (GSAS), a cross-sectional multicenter collaborative study, used a stereo fundus camera (nonmyd WX) to assess various morphological parameters of the optic nerve head (ONH) in glaucoma patients. We examined the associations between the Disc Damage Likelihood Scale (DDLS), a grading system for estimating glaucomatous ONH damage, and each parameter. METHODS: The study included 187 eyes of 187 patients with primary open-angle glaucoma or normal-tension glaucoma. ONH morphological parameters including the DDLS stage were calculated with prototype analysis software. Three independent graders classified each optic disc appearance into four different types: focal ischemic, myopic glaucomatous, senile sclerotic, and generalized enlargement. The correlations between the DDLS and patient characteristics or each ONH parameter were analyzed with Spearman's rank correlation coefficient. RESULTS: The DDLS was correlated positively with baseline intraocular pressure and visual field pattern standard deviation, and negatively with visual field mean deviation. The DDLS was strongly correlated with vertical cup-to-disc ratio and horizontal cup-to-disc ratio positively, and with minimum rim-disc ratio negatively. The mean DDLS stage in the myopic glaucomatous type tended to be higher than the scores in other types. CONCLUSION: The DDLS obtained through three-dimensional ONH analysis correlates well with the severity of glaucomatous ONH and visual field damage.

Diagnostic classification of macular ganglion cell and retinal nerve fiber layer analysis: differentiation of false-positives from glaucoma.

PURPOSE: To investigate the rate and associated factors of false-positive diagnostic classification of ganglion cell analysis (GCA) and retinal nerve fiber layer (RNFL) maps, and characteristic false-positive patterns on optical coherence tomography (OCT) deviation maps. DESIGN: Prospective, cross-sectional study. PARTICIPANTS: A total of 104 healthy eyes of 104 normal participants. METHODS: All participants underwent peripapillary and macular spectral-domain (Cirrus-HD, Carl Zeiss Meditec Inc, Dublin, CA) OCT scans. False-positive diagnostic classification was defined as yellow or red color-coded areas for GCA and RNFL maps. Univariate and multivariate logistic regression analyses were used to determine associated factors. Eyes with abnormal OCT deviation maps were categorized on the basis of the shape and location of abnormal color-coded area. Differences in clinical characteristics among the subgroups were compared. MAIN OUTCOME MEASURES: (1) The rate and associated factors of false-positive OCT maps; (2) patterns of false-positive, color-coded areas on the GCA deviation map and associated clinical characteristics. RESULTS: Of the 104 healthy eyes, 42 (40.4%) and 32 (30.8%) showed abnormal diagnostic classifications on any of the GCA and RNFL maps, respectively. Multivariate analysis revealed that false-positive GCA diagnostic classification was associated with longer axial length and larger fovea-disc angle, whereas longer axial length and smaller disc area were associated with abnormal RNFL maps. Eyes with abnormal GCA deviation map were categorized as group A (donut-shaped round area around the inner annulus), group B (island-like isolated area), and group C (diffuse, circular area with an irregular inner margin in either). The axial length showed a significant increasing trend from group A to C (P=0.001), and likewise, the refractive error was more myopic in group C than in groups A (P=0.015) and B (P=0.014). Group C had thinner average ganglion cell-inner plexiform layer thickness compared with other groups (group A=B>C, P=0.004). CONCLUSIONS: Abnormal OCT diagnostic classification should be interpreted with caution, especially in eyes with long axial lengths, large fovea-disc angles, and small optic discs. Our findings suggest that the characteristic patterns of OCT deviation map can provide useful clues to distinguish glaucomatous changes from false-positive findings.

Novel use of 3T MRI in assessment of optic nerve volume in glaucoma.

PURPOSE: To measure optic nerve (ON) volume using 3 T magnetic resonance imaging (MRI), to correlate ON volume with retinal nerve fiber layer (RNFL) thickness, and to determine the viability of MRI as an objective tool in distinguishing glaucoma severity. METHODS: In this cross-sectional study, 30 severe glaucoma patients, 30 mild glaucoma patients and 30 age-matched controls were recruited. All subjects underwent standard automated perimetry, RNFL analysis and 3 T MRI examinations. Glaucoma patients were classified according to the Hodapp-Anderson-Parish classification. Pearson's correlation coefficient was used to correlate ON volume with RNFL, and receiver operating curve (ROC) analysis was performed to determine the sensitivity and specificity of ON volume in detecting glaucoma severity. RESULTS: Optic nerve volume was significantly lower in both the left and right eyes of the severe glaucoma group (168.70 ± 46.28 mm(3); 167.40 ± 45.36 mm(3)) than in the mild glaucoma group (264.03 ± 78.53 mm(3); 264.76 ± 78.88 mm(3)) and the control group (297.80 ± 71.45 mm(3); 296.56 ± 71.02 mm(3)). Moderate correlation was observed between: RNFL thickness and ON volume (r = 0.51, p <0.001), and in mean deviation of visual field and optic nerve volume (r = 0.60, p < 0.001). ON volume below 236 mm(3) was 96 % sensitive and 80 % specific for the detection of severe glaucoma. CONCLUSIONS: MRI measured optic nerve volume is a reliable method of assessing glaucomatous damage beyond the optic nerve head. A value of 236 mm(3) and below can be used to define severe glaucoma.

Validity of a new optic disc grading software for use in clinical and epidemiological research.

BACKGROUND: To determine the reliability and agreement of a new optic disc grading software program for use in clinical, epidemiological research. DESIGN: Reliability and agreement study. SAMPLES: 328 monoscopic and 85 stereoscopic optic disc images. METHODS: Optic disc parameters were measured using a new optic disc grading software (Singapore Optic Disc Assessment) that is based on polynomial curve-fitting algorithm. Two graders independently graded 328 monoscopic images to determine intergrader reliability. One grader regraded the images after 1 month to determine intragrader reliability. In addition, 85 stereo optic disc images were separately selected, and vertical cup-to-disc ratios were measured using both the new software and standardized Wisconsin manual stereo-grading method by the same grader 1 month apart. Intraclass correlation coefficient (ICC) and Bland-Altman plot analyses were performed. MAIN OUTCOME MEASURES: Optic disc parameters. RESULTS: The intragrader and intergrader reliability for optic disc measurements using Singapore Optic Disc Assessment was high (ICC ranging from 0.82 to 0.94). The mean differences (95% limits of agreement) for intergrader vertical cup-to-disc ratio measurements were 0.00 (-0.12 to 0.13) and 0.03 (-0.15 to 0.09), respectively. The vertical cup-to-disc ratio agreement between the software and Wisconsin grading method was extremely close (ICC = 0.94). The mean difference (95% limits of agreement) of vertical cup-to-disc ratio measurement between the two methods was 0.03 (-0.09 to 0.16). CONCLUSIONS: Intragrader and intergrader reliability using Singapore Optic Disc Assessment was excellent. This software was highly comparable with standardized stereo-grading method. Singapore Optic Disc Assessment is useful for grading digital optic disc images in clinical, population-based studies.

Retinal imaging: what the neurologist needs to know.

With the advent of confocal microscopy and optical coherence tomography, high-resolution multimodal imaging of the retina and optic nerve head can now be obtained routinely, providing new diagnostic clues in a variety of neuro-ophthalmological conditions. In this review, we provide an overview of these imaging advances and their clinical applications.

Definition of glaucoma: clinical and experimental concepts.

Glaucoma is a term describing a group of ocular disorders with multi-factorial etiology united by a clinically characteristic intraocular pressure-associated optic neuropathy. It is not a single entity and is sometimes referred to in the plural as the glaucomas. All forms are potentially progressive and can lead to blindness. The diverse conditions that comprise glaucoma are united by a clinically characteristic optic neuropathy: glaucomatous optic neuropathy (GON). Evidence suggests that the primary site of neurological injury is at the optic nerve head. This fact enables the conditions to be grouped, irrespective of the causal mechanism(s). The term experimental glaucoma implies model resemblance to the human condition. We propose that 'experimental glaucoma' be restricted to animal models with demonstrable features of GON and/or evidence of a primary axonopathy at the optic nerve head. A fundamental inadequacy in this framework is any reference to the pathogenesis of GON, which remains unclear.

[Hereditary optic neuropathies]. / Neuropathies optiques héréditaires.

Hereditary optic neuropathies are a group of heterogeneous conditions affecting both optic nerves, with an autosomal dominant, autosomal recessive, X-related or mitochondrial transmission. The two most common non-syndromic hereditary optic neuropathies (Leber's hereditary optic neuropathy and autosomal dominant optic atrophy) are very different in their clinical presentation and their genetic transmission, leading however to a common, non-specific optic nerve atrophy. Beyond the optic atrophy-related visual loss, which is the clinical hallmark of this group of diseases, other associated neurological signs are increasingly recognized.

Agreement and accuracy of non-expert ophthalmologists in assessing glaucomatous changes in serial stereo optic disc photographs.

PURPOSE: To compare the interobserver agreement in detecting glaucomatous optic disc changes using serial stereophotography between a large group of non-expert ophthalmologists and glaucoma specialists; to assess the accuracy of non-experts; to investigate whether the interobserver agreement and the accuracy of non-experts changed after a training session. DESIGN: Masked interobserver agreement study. PARTICIPANTS: Serial optic disc stereophotos from 40 patients with glaucoma. METHODS: Three independent experienced glaucoma specialists (readers of the European Glaucoma Prevention Study) evaluated a set of 2 serial optic disc color stereo-slides for glaucomatous change, obtained with a delay varying from 2 to 7 years of 40 patients, masked from the temporal sequence of the slides. Each patient was graded as changed or stable by agreement of 2 of 3 of the experts (the reference standard). Thirty-seven non-expert ophthalmologists independently evaluated the same set of serial optic disc stereo-slides twice, with the second evaluation on the same day, masked from the results of the previous evaluation, after a training session on a separate slide set. MAIN OUTCOME MEASURES: Interobserver agreement of non-experts and experts in detecting glaucomatous optic disc changes (expressed as kappa coefficient); agreement of non-experts with the reference standard (accuracy) before and after a training session. RESULTS: The interobserver kappa coefficient (κ) of the non-experts and experts was 0.20 (95% confidence interval [CI], 0.19-0.21) and 0.51 (95% CI, 0.33-0.69), respectively (P<0.0001). The mean κ of the non-experts with the reference standard was 0.33 (95% CI, 0.27-0.39). After a training session, the interobserver agreement of the non-experts increased from 0.20 to 0.27 (95% CI, 0.26-0.28) (P<0.0001). The percentage agreement of the non-experts with the reference standard improved from 68.5% before to 71.4% after the training session (Wilcoxon signed-rank test, P=0.034). CONCLUSIONS: The interobserver agreement of non-expert ophthalmologists in detecting glaucomatous optic disc changes using serial stereophotos was significantly lower than that of experts, which was moderate. After a training session, the interobserver agreement and the accuracy of the non-experts showed a small but statistically significant improvement.

Deep learning assisted detection of glaucomatous optic neuropathy and potential designs for a generalizable model.

PURPOSE: To evaluate ways to improve the generalizability of a deep learning algorithm for identifying glaucomatous optic neuropathy (GON) using a limited number of fundus photographs, as well as the key features being used for classification. METHODS: A total of 944 fundus images from Taipei Veterans General Hospital (TVGH) were retrospectively collected. Clinical and demographic characteristics, including structural and functional measurements of the images with GON, were recorded. Transfer learning based on VGGNet was used to construct a convolutional neural network (CNN) to identify GON. To avoid missing cases with advanced GON, an ensemble model was adopted in which a support vector machine classifier would make final classification based on cup-to-disc ratio if the CNN classifier had low-confidence score. The CNN classifier was first established using TVGH dataset, and then fine-tuned by combining the training images of TVGH and Drishti-GS datasets. Class activation map (CAM) was used to identify key features used for CNN classification. Performance of each classifier was determined through area under receiver operating characteristic curve (AUC) and compared with the ensemble model by diagnostic accuracy. RESULTS: In 187 TVGH test images, the accuracy, sensitivity, and specificity of the CNN classifier were 95.0%, 95.7%, and 94.2%, respectively, and the AUC was 0.992 compared to the 92.8% accuracy rate of the ensemble model. For the Drishti-GS test images, the accuracy of the CNN, the fine-tuned CNN and ensemble model was 33.3%, 80.3%, and 80.3%, respectively. The CNN classifier did not misclassify images with moderate to severe diseases. Class-discriminative regions revealed by CAM co-localized with known characteristics of GON. CONCLUSIONS: The ensemble model or a fine-tuned CNN classifier may be potential designs to build a generalizable deep learning model for glaucoma detection when large image databases are not available.

Prevalence and determinants of angle closure in central Sri Lanka: the Kandy Eye Study.

PURPOSE: To determine the prevalence and determinants of angle closure in the Kandy District of central Sri Lanka. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: Inhabitants aged 40 years or more from villages in the Kandy District were selected by randomized cluster sampling; 1721 eligible participants were identified, and 1375 participated in the study. METHODS: The examination included slit-lamp examination of the anterior segment, applanation tonometry, static and dynamic gonioscopy, dilated stereoscopic optic disc examination, and ultrasonic ocular biometry. Eyes that were primary angle-closure suspects (PACS) or had primary angle closure (PAC) or primary angle-closure glaucoma (PACG) were identified. Definitions were based on recommendations from the International Society for Geographic and Epidemiological Ophthalmology (ISGEO). Univariate and multivariate logistic regression analyses were performed with angle closure as the outcome variable. MAIN OUTCOME MEASURES: Subjects with PACG, PACS, or PAC were pooled into a group considered to have angle closure. RESULTS: The prevalence of PACS, PAC, and PACG in at least 1 eye was 2.35% (95% confidence interval [CI], 0.0-4.7; 32 subjects), 1.86% (95% CI, 0.6-3.1, 25 participants), and 0.57% (95% CI, 0.0-1.2; 7 participants), respectively. The overall prevalence of angle closure was 4.7% (95% CI, 1.1-9.3; 64 participants). The mean axial length in those with angle closure (21.99 mm) was significantly shorter (P<0.001) than in those with open angles (22.47 mm), as was the mean anterior chamber depth (ACD) (2.47 mm compared with 2.81 mm), but the mean lens thickness in those with angle closure (4.51 mm) did not significantly differ (P = 0.44) from those with open angles (4.45 mm). Neither age nor nuclear opalescence was a significant predictor of angle closure in the multivariate model (P = 0.09 and 0.61, respectively); however, female gender was associated with a 9.2 times (P<0.001) increased risk of angle closure, and each millimeter decrease in ACD was associated with a 2.6 times increased risk of angle closure (P<0.001). CONCLUSIONS: The overall prevalence of angle closure was 4.7%. Female gender and shallow ACD were significant independent predictors of angle closure in this Sri Lankan population.

Sensitivity and specificity of the Heidelberg Retina Tomograph II Version 3.0 in a population-based study: the Tajimi Study.

PURPOSE: To evaluate the sensitivity and specificity of the 3 glaucoma classification programs, the FS Mikelberg discriminant function (FSM), Moorfields Regression Analysis (MRA), and Glaucoma Probability Score (GPS) of version 3.0 of the Heidelberg Retina Tomograph (HRT) II (Heidelberg Engineering, Dossenheim, Germany), in a population-based setting for the first time. DESIGN: Population-based cross-sectional study. PARTICIPANTS: One randomly chosen eye of each subject without glaucoma, subject with glaucoma, and subject with suspected glaucoma with reliable HRT II measurements from the Tajimi study (2297 eyes of 2297 subjects) were included for analysis. METHODS: Glaucoma was diagnosed by the optic disc and visual field findings according to the criteria of the International Society of Geographical and Epidemiological Ophthalmology. The sensitivity and specificity of FSM, MRA, and GPS were calculated. Characteristics of erroneously diagnosed glaucoma (false-negative) eyes and factors that influenced specificity with the 3 programs were investigated. MAIN OUTCOME MEASURES: Sensitivity and specificity of FSM, MRA, and GPS. RESULTS: Sensitivity and specificity varied significantly among the 3 programs: 59.1%, 39.4%, and 65.2% (P = 0.02 approximately 0.003, chi-square test), and 86.7%, 96.1%, and 83.0% (P<0.0001) with FMS, MRA, and GPS, respectively. MRA gave the lowest sensitivity but the highest specificity. Positive predictive values for these programs ranged between 0.10 and 0.23, whereas negative predictive values ranged between 0.98 and 0.99. False-negative eyes had significantly better visual field indexes (P<0.01 approximately 0.002, Mann-Whitney U test) and smaller cup and larger rim parameters compared with true-positive glaucoma eyes. Older age and hyperopia were negatively correlated with the specificity of GPS but not with that of FMS and MRA. Larger disc area was significantly associated with decreased specificity of all programs. CONCLUSIONS: In a population-based setting, the sensitivity of the HRT II was unsatisfactory with any of the classification programs, whereas specificity was satisfactory. A significant percentage of the glaucoma discs were labeled as normal, and eyes in the earlier stage of the disease appear to be more likely to be misdiagnosed as normal. Factors such as age, refraction, and disc area had an influence on specificity, but the degree of its influence was different for each classification program.

I-125 brachytherapy for choroidal melanoma photographic and angiographic abnormalities: the Collaborative Ocular Melanoma Study: COMS Report No. 30.

OBJECTIVES: (1) To summarize the protocol used for grading features of postradiation abnormalities from fundus photographs and fluorescein angiograms of patients enrolled in the Collaborative Ocular Melanoma Study (COMS); (2) to document the prevalence of features of interest in the posterior pole of these eyes during 8 years of follow-up; and (3) to investigate baseline patient, tumor, and treatment characteristics associated with posterior pole features. DESIGN: Observational case series within a randomized, multicenter clinical trial. PARTICIPANTS: We evaluated 650 patients who were assigned to and received iodine-125 brachytherapy in the COMS for medium-sized tumors. METHODS: Color fundus photographs and fluorescein angiograms were taken at baseline and 2, 5, and 8 years; 30 features were graded according to a standard protocol. MAIN OUTCOME MEASURES: Prevalence at selected time intervals of fundus photographic features associated with retinopathy and optic neuropathy. RESULTS: The percentage of patients with >/=1 feature of interest was 49.2% at baseline, 84.4% at 2 years, 91.2% at 5 years, and 90.7% at 8 years. The most frequent findings across all follow-up examinations were macular microaneurysms (75.6% of examinations), macular angiographic leakage (75.1%), and optic disc hyperfluorescence (62.8%). The median number of features present increased significantly with each follow-up to a maximum of 7 features at 8 years. The prevalence of neovascularization of the disc at 5 years was 5.2%. The prevalence of optic neuropathy at 5 years was 27.4%. Prognostic factors for more prevalent and severe posterior pole abnormalities were diabetes, tumor location close to both optic nerve and foveal avascular zone, and greater dose of radiation to the foveola and optic nerve head. CONCLUSIONS: The amount and severity of retinopathy and optic neuropathy after iodine-125 brachytherapy increased through 8 years of follow-up. Assessment of photographs and angiograms taken in accord with a standard protocol provided reliable estimates of rates of development of features of retinopathy and optic neuropathy in eyes treated using the COMS brachytherapy protocol. Our findings support earlier reports that tumor factors in addition to radiation treatment may contribute to posterior pole abnormalities. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.

Evaluating a new disc staging scale for glaucomatous damage: the ability to detect change over time.

PURPOSE: To assess the ability of Disc Damage Likelihood Scale (DDLS) in detecting glaucomatous changes in the optic nerve on sequential optic disc stereo-photographs as compared with three other different cup/disc grading systems (C/D). METHODS: Eighty-three pairs of stereo-photographs with a minimum of 5-year follow-up were examined by one group of three observers masked to chronological order by using their clinical expertise. Their conclusions were considered gold standard. Another group of three glaucoma experts examined the same masked pairs to evaluate glaucomatous changes using four different optic nerve grading systems: DDLS, vertical, horizontal, and maximal cup/disc. Ratings of these four methods in the second group were then compared with the gold standard. RESULTS: Baseline and follow-up photographs of 83 eyes were included. Mean follow-up was 6 years. The sensitivities for detecting glaucomatous nerve changes were 71.4%, 63.9%, 66.7%, and 47.2% for DDLS, vertical, horizontal, and maximal cup/disc, respectively. The specificity for finding nerve change was 70.9%, 51.1%, 40.4%, and 48.9%, respectively. The proportion of photographs identified as showing glaucomatous changes differed significantly between the DDLS and vertical C/D (VCD) (X2=7.900, p=0.005), between the DDLS and horizontal C/D (HCD) (X2=13.89, p=0.000), and between DDLS and maximum C/D (MCD) (X2=4.192, p=0.041). The largest area (74.4%) under the receiver operator characteristic curve was obtained by using the DDLS. CONCLUSIONS: DDLS had higher sensitivity and specificity for detecting glaucomatous changes versus the other three C/Ds when considering sequential stereo-photographs.

Artificial neural network-based glaucoma diagnosis using retinal nerve fiber layer analysis.

PURPOSE: To develop, train, and test an artificial neural network (ANN) for differentiating among normal subjects, primary open angle glaucoma (POAG) suspects, and persons with POAG in Asian-Indian eyes using inputs from clinical parameters, optical coherence tomography (OCT), visual fields, and GDx nerve fiber analyzer. METHODS: One hundred eyes were classified using optic disc examination and perimetry into normal (n=35), POAG suspects (n=30), and POAG (n=35). EasyNN-plus simulator was used to develop an ANN model with inputs including age, sex, myopia, intraocular pressure (IOP), optic nerve head, and retinal nerve fiber layer (RNFL) parameters on OCT, Octopus 30-2 full threshold visual field, and GDx parameters. RESULTS: With two outputs (POAG or normal), specificity was 80% and sensitivity was 93.3%. Ninety percent of POAG suspects were labeled as abnormal in this analysis. ANN assigned the highest importance to Smax/Imax RNFL on OCT followed by cup-area (OCT) and other RNFL parameters (OCT) for two outputs. With three outputs (normal, POAG, and POAG suspect), ANN gave an overall classification rate of 65%, specificity of 60%, and sensitivity of 71.4% with a target error rate of the training set at 1%. The parameters for three outputs, in decreasing order of relative importance, were Savg, vertical cup-disc ratio, cup-volume, and cup-area on OCT. CONCLUSIONS: An ANN taking varied diagnostic imaging inputs was able to separate POAG eyes from normal subjects and POAG suspects. The network had reasonable sensitivity with three outputs; however, it had a tendency to mislabel POAG suspects as POAG.

Classification of macular and optic nerve disease by principal component analysis.

In this study, pattern electroretinography (PERG) signals were obtained by electrophysiological testing devices from 70 subjects. The group consisted of optic nerve and macular diseases subjects. Characterization and interpretation of the physiological PERG signal was done by principal component analysis (PCA). While the first principal component of data matrix acquired from optic nerve patients represents 67.24% of total variance, the first principal component of the macular patients data matrix represents 76.81% of total variance. The basic differences between the two patient groups were obtained with first principal component, obviously. In addition, the graphic of second principal component vs. first principal component of optic nerve and macular subjects was analyzed. The two patient groups were separated clearly from each other without any hesitation. This research developed an auxiliary system for the interpretation of the PERG signals. The stated results show that the use of PCA of physiological waveforms is presented as a powerful method likely to be incorporated in future medical signal processing.

[Phenotype of the visual system in oculocutaneous and ocular albinism]. / Phänotyp des visuellen Systems bei okulokutanem und okulärem Albinismus.

In spite of albinism being one of the visual impairments which has been known for over a century, it has only been known for a few decades that albinism is correlated to severe cerebral morphological developmental alterations. The increasing knowledge about the role of melanin in the development and orientation of cerebral neurons not only renders more insight into albinism, but also a greater insight in the physiological neuronal and cerebral development in man. Concerning the morphological and visual phenotype there are new clinical findings which enlarge the known spectrum of albinism. In a representative group of 506 persons with oculocutaneous and ocular albinism who are in care at the Department of Ophthalmology at the University of Saarland (UKS), we present a staging of morphological findings of the iris, retinal pigment epithelium and macula, and of the optic nerve head which has been in use for 10 years. Albinism may present with a remarkably mild ocular phenotype and a near to normal functional phenotype. We present correlations between molecular genetic types of albinism, ocular phenotype and visual function. Of great importance concerning later visual acuity is the dysplasia of the optic nerve head (ONH), which is a frequent finding in albinism. The appearance of the ONH should always be included in any clinical description of an albinism patient. It is highly possible that due to a moderate phenotype there are still many patients who have not been diagnosed yet. Visual acuity of 30/20 to 20/20 and no nystagmus do not rule out albinism. In addition, when performing albino VEPs in phenotypically normal children with infantile strabismus, small ONHs, but normal visual acuity and no nystagmus, the classical atypical chiasmal crossing is sometimes found. Therefore, the number of persons having undiagnosed albinism is probably quite high, perhaps there even is a very broad transition zone from normal to albinotic.