Optic Nerve Head Appearance Research Articles

The BONSAI (Brain and Optic Nerve Study with Artificial Intelligence) deep learning system can accurately identify pediatric papilledema on standard ocular fundus photographs

BackgroundPediatric papilledema often reflects an underlying severe neurologic disorder and may be difficult to appreciate, especially in young children. Ocular fundus photographs are easy to obtain even in young children and in nonophthalmology settings. The aim of our study was to ascertain whether an improved deep-learning system (DLS), previously validated in adults, can accurately identify papilledema and other optic disk abnormalities in children. MethodsThe DLS was tested on mydriatic fundus photographs obtained in a multiethnic pediatric population (<17 years) from three centers (Atlanta-USA; Bucharest-Romania; Singapore). The DLS’s multiclass classification accuracy (ie, normal optic disk, papilledema, disks with other abnormality) was calculated, and the DLS’s performance to specifically detect papilledema and normal disks was evaluated in a one-vs-rest strategy using the AUC, sensitivity and specificity, with reference to expert neuro-ophthalmologists. ResultsExternal testing was performed on 898 fundus photographs:447 patients; mean age, 10.33 (231 patients ≤10 years of age; 216, 11-16 years); 558 normal disks, 254 papilledema, 86 other disk abnormalities. Overall multiclass accuracy of the DLS was 89.6% (range, 87.8%-91.6%). The DLS successfully distinguished “normal” from “abnormal” optic disks (AUC 0.99 [0.98-0.99]; sensitivity, 87.3% [84.9%-89.8%]; specificity, 98.5% [97.6%-99.6%]), and “papilledema” from “normal and other” (AUC 0.99 [0.98-1.0]; sensitivity, 98.0% [96.8%-99.4%]; specificity, 94.1% (92.4%-95.9%)]. ConclusionsOur DLS reliably distinguished papilledema from normal optic disks and other disk abnormalities in children, suggesting it could be utilized as a diagnostic aid for the assessment of optic nerve head appearance in the pediatric age group.

Detecting glaucoma from fundus images using ensemble learning

Abstract Glaucomatous changes of the optic nerve head could be detected from fundus images. Focusing on optic nerve head appearance, and its difference from healthy images, altogether with the availability of plenty of such images in public fundus image databases, these images are ideal sources for artificial intelligence methods applications. In this work, we used ensemble learning methods and compared them with various single CNN models (VGG-16, ResNet-50, and MobileNet). The models were trained on images from REFUGE public dataset. The average voting ensemble method outperformed all mentioned models with 0.98 accuracy. In the AUC metric, the average voting ensemble method outperformed VGG-16 and MobileNet models, which had significantly weaker performance when used alone. The best results were observed using the ResNet-50 model. These results confirmed the significant potential of ensemble learning in enhancing the overall predictive performance in glaucomatous changes detection, but the overall performance could be negatively affected when models with weaker prediction performance are included.

Pharmacological Approaches to Modulate the Scarring Process after Glaucoma Surgery.

Glaucoma is an acquired optic neuropathy that results in a characteristic optic nerve head appearance and visual field loss. Reducing the IOP is the only factor that can be modified, and the progression of the disease can be managed through medication, laser treatment, or surgery. Filtering procedures are used when target pressure cannot be obtained with less invasive methods. Nevertheless, these procedures require accurate control of the fibrotic process, which can hamper filtration, thus, negatively affecting the surgical success. This review explores the available and potential pharmacological treatments that modulate the scarring process after glaucoma surgery, analyzing the most critical evidence available in the literature. The modulation of scarring is based on non-steroidal anti-inflammatory drugs (NSAIDs), mitomycin, and 5-fluorouracil. In the long term, the failure rate of filtering surgery is mainly due to the limitations of the current strategies caused by the complexity of the fibrotic process and the pharmacological and toxicological aspects of the drugs that are currently in use. Considering these limitations, new potential treatments were investigated. This review suggests that a better approach to tackle the fibrotic process may be to hit multiple targets, thus increasing the inhibitory potential against excessive scarring following surgery.

Patients with septo-optic dysplasia: General ophthalmologic assessment and retinal imaging.

To evaluate the functional development and, retinal and optic disc morphology using OCT in patients with septo-optic dysplasia (SOD). This retrospective case series included patients diagnosed with SOD between 2007 and 2020. Ophthalmologic assessment included visual acuity (VA) and funduscopy at the initial and last presentation. Retinal imaging included OCT of the macula analyzing the retinal morphology, central retinal thickness volume (CRT) and ganglion cell layer (GCL). Also, scans of the optic nerve head were taken to evaluate the retinal nerve fiber layer (RNFL) and global value. 38 eyes of 19 children with a mean age 6.3 ± 5.3 years were included. 31.6% showed all 3 characteristics of SOD, whereof ONH, midline defects and endocrine dysfunctions were found in 94.7%, 89.5% and 47.4% respectively. The mean VA was 0.70 ± 0.66logMar in the right eye (RE) and 0.40 ± 0.55logMar in the left eye (LE) at the initial presentation. No change of vision (RE: 0.69 ± 0.71logMar; LE: 0.31 ± 0.57logMar) was found after a follow-up period of 6.3 ± 4.5years. Funduscopy showed an ONH in 79% (n = 30/38), tortuous retinal vessels in 36.8% (n = 14/38) and a double-ring sign in 15.8% (n = 6/38). Retinal imaging showed variable morphology. 6 eyes of 4 patients showed temporal retinal thinning with corresponding GCL attenuation. The optic nerve head appearance varied between no changes, sectoral and hemispherical reduction. Patients suffering from SOD show diverse expression of retinal changes such as retinal, GCL and RNFL thinning in OCT. Furthermore, visual function remained stable during follow-up examinations, indicating no further alteration due to underlying pathology.

Light‐field fundus imaging under astigmatism – An eye model study

AbstractPurposeOne strong risk factor for glaucoma is a suspicious optic nerve head appearance and an increase in depth. With the upcoming light‐field (LF) technology one‐shot 3D retinal imaging and measuring is possible. Due to optical aberrations such as astigmatism, the imaged depth can be distorted. The study presented here investigated the influence of astigmatism on LF image quality and depth estimation using an eye model.MethodsWe developed a new eye model that added astigmatism by integrating an additional cylindrical lens between the cornea and lens. We used cylindrical lenses from −4 to 0 dpt in 1 dpt steps in vertical and horizontal orientations. The fundus was modelled as a half hollow sphere with a radius of 10 mm and a central papilla with 0.8 mm depth. The fundus was coated with red acrylic lacquer, and vessels were drawn with a thin brush with black acrylic lacquer. LF fundus images (15 for each cylindrical lens and orientation) were taken with a fundus camera (FF450, Carl Zeiss Meditec AG, Germany) equipped with an industrial LF camera (RX12, Raytrix GmbH, Germany). Depth measurements were performed with the Raytrix LF software (RxLive 5.0.046.0) as difference from a vertical vessel to a horizontal orientated vessel. The same measuring point was used for all images.ResultsThe LF images taken with a cylindrical lens show a visually poorer image quality. Depth estimates were only possible in the central image area. The fundus images show increasing depth differences between vertical and horizontal vessels with increasing astigmatism up to 0.37 mm at −4 dpt in contrast to the flat imaged fundus without cylindrical lens. The sign of the depth differences changes when the orientation of the inserted cylindrical lens is changed.ConclusionsThe imaged LF of a fundus of an astigmatic eye model is measurably distorted and affects vertical and horizontal structures differently. This must be taken into account when evaluating and interpreting LF depth measurements.

Optic nerve head assessment in Light‐field fundus images – A case study

AbstractPurposeA suspicious optic nerve head (ONH) appearance, with abnormal cupping or increased cup‐to‐disc ratio, is associated to a strong risk factor for glaucoma. Typical devices to analyse the structure of the ONH are optical coherence tomography or scanning laser ophthalmoscopy. Those devices provide parameters to describe the status of an ONH like its depth, width or volume. We show that these parameters for glaucoma diagnosis can be obtained with a commercial fundus camera using an adapted light field (LF) camera providing a one‐shot 3d retinal image.MethodsWe examined a human eye (32 years, male) 5 times during one session in compliance with the Declaration of Helsinki. The images were taken with a fundus camera (FF450, Carl Zeiss Meditec AG, Germany) combined with an industrial LF camera (RX12, Raytrix GmbH, Germany). The generic depth estimation was performed with the Raytrix LF software (RxLive 5.0.031.0) using the Depth Raycast Light algorithm. The results were exported as 3d point lists in ascii XYZ format and for further processing imported in Matlab (R2018b, MathWorks, U.S.). The imported data were pre‐processed, the papilla midpoints automatically detected and the optic nerve head was horizontally sliced in 0.01 virtual depth steps starting from the base upwards until the papilla rim was reached. We compared the overall virtual depth, the virtual volume and the virtual area per virtual depth step, each as relative difference.ResultsAll LF images showed visually a very good image quality. The depth estimations were successful and covered the complete image areas. The overall virtual depth range was 95.9% to 101.4% with mean of 100% (±2.36%). The overall virtual volume range was 97.5% to 102.2% with mean of 100% (±2.1%). The area per virtual depth range was 2.5% to 174.5% with mean of 100% (±10.9%) whereas the larger deviations appeared in the lowermost slices.ConclusionsFundus cameras with LF technique are able to provide one‐shot 3d retinal images. This light field images allow the evaluation of typical parameters for glaucoma diagnosis and show a very good reproducibility.

Biomarkers of lesion severity in a rodent model of nonarteritic anterior ischemic optic neuropathy (rNAION).

The rodent model of nonarteritic anterior ischemic optic neuropathy (rNAION) is similar in many of its pathophysiological responses to clinical NAION. Like human NAION, there is significant variability in the severity of the lesion produced, and little is known of the parameters associated with rNAION induction severity or if pre- or early post-induction biomarkers can be identified that enable prediction of lesion severity and ultimate loss of retinal ganglion cells (RGCs). Adult male Sprague-Dawley outbred rats were evaluated for various parameters including physiological characteristics (heart rate, respiratory rate, temperature, hematocrit [Hct]), optic nerve head (ONH) appearance, pre- and post-induction mean diameter, and intravenous fluorescein and indocyanine green angiographic patterns of vascular leakage at 5 hours post-induction, performed using a spectral domain-optical coherence tomography (SD-OCT) instrument. Early changes were correlated with ultimate RGC loss by Brn3a (+) immunohistology. RGC loss also was correlated with the relative level of laser exposure. The severity of ONH edema 2d, but not 5hr, post induction was most closely associated with the degree of RGC loss, revealing a threshold effect, and consistent with a compartment syndrome where a minimum level of capillary compression within a tight space is responsible for damage. RGC loss increased dramatically as the degree of laser exposure increased. Neither physiological parameters nor the degree of capillary leakage 5hr post induction were informative as to the ultimate degree of RGC loss. Similar to human NAION, the rNAION model exhibits marked variability in lesion severity. Unlike clinical NAION, pre-induction ONH diameter likely does not contribute to ultimate lesion severity; however, cross-sectional ONH edema can be used as a biomarker 2d post-induction to determine randomization of subjects prior to inclusion in specific neuroprotection or neuroregeneration studies.

Light‐field imaging for glaucoma diagnosis—reproducibility on one patient

PurposeA suspicious optic nerve head appearance with abnormal cupping or increased cup‐to‐disc ratio is considered as a strong risk factor for glaucoma. Typical systems to measure this deformation are optical coherence tomography or scanning laser ophthalmoscopy. We show that the needed depth information for glaucoma diagnosis can be obtained reliably with a commercial fundus camera using an adapted light‐field camera providing a one‐shot 3d retinal image.MethodsWe examined the left eye of a glaucoma suspect (male, 39 years) 11 times in compliance with the Declaration of Helsinki. For each examination, the glaucoma suspect repositioned himself and the device was readjusted. The images were taken with a fundus camera (FF450, Carl Zeiss Meditec AG) combined with a modified light‐field camera (Raytrix R12, Raytrix GmbH). The eye was illuminated with a wavelength of 520 nm (±20 nm). The absolute virtual depth (VD) values were exported from the Raytrix software (RxLive 5.0, Raytrix GmbH) and further processed in Matlab R2018. All data were aligned to each other to measure at similar locations. The maximum VD on a vessel segment above the rim and the minimum above the root of the vessel inside the optic nerve head was determined to calculate the depth difference.ResultsAll images showed a clearly identifiable optic nerve head structure and allowed a successful and reliable determination of the depth information. The average relative depth difference over all examinations was 6.1 ± 0.34VD. The 95% confidence interval was between 5.86 and 6.34VD. Besides the depth values also the lateral values are virtual because of an aperture mismatch between fundus camera and light‐field camera. A successful depth estimations of the Raytrix software require high contrast images with textures. Caused by the objective of the fundus camera image distortions existed.ConclusionsThe presented results from our preliminary system show the potential of the light‐field technique to be used for glaucoma diagnostics and progression analysis based on the optic nerve head in 3D. Reliable and reproducible measurements of this technique can enhance the informative value of the classical fundus photography.

Light‐Field imaging of the human optic nerve head at different wavelengths—a case study

PurposeOne strong risk factor for glaucoma is a suspicious optic nerve head appearance with an abnormal cupping or an increase in the cup‐to‐disc ratio. To measure such geometric characteristics, typically scanning systems like OCT or SLO are used. We present that one‐shot 3D retinal imaging and measuring with a commercial fundus camera using an industrial light‐field camera is possible and works best in the green spectrum.MethodsTo demonstrate 3D imaging at the human optic nerve head (ONH), we examined one eye with suspected glaucoma (patient:37 years, male). ONH centered 30° images of the right eye were taken after pupil dilatation with Tropicamid with a Zeiss FF450 fundus camera (Carl Zeiss Meditec AG, Germany), to which an industrial light‐field camera (Raytrix GmbH, Germany) was attached. The images were taken at 450 nm, 520 nm, 600 nm and 650 nm centroid wavelengths, 40 nm bandwidth each. The maximum depth of the papilla was determined in virtual depth (VD) using the Raytrix software (RxLive, Raytrix GmbH, Germany). The results were compared among each other concerning the vessel contrast, quantity of measurement points and subjectively where they were found.ResultsThe light‐field images showed clearly the ONH in 3D. The highest image contrast was found at 450 nm, whereby the contrast decreases with increasing illumination wavelengths. Most measurement points around the papilla were found at 520 nm followed by 450 nm with a slightly lower number. At 600 nm, the number of measurement points was significantly reduced. Worst results were found at 650 nm. Plausible measurement points were only found in image regions with high contrast. Those regions were vessel borders and the papilla border.ConclusionsUsing the light‐field technique in fundus photography, it is possible to image and to measure the ONH in 3D. Screening for glaucoma and glaucoma diagnosis can be much improved taking into account that, in principle, classical fundus imaging offer only 2D data.

Glaucoma-Related Adverse Events at 10 Years in the Infant Aphakia Treatment Study

Glaucoma-related adverse events constitute serious complications of cataract removal in infancy, yet long-term data on incidence and visual outcome remain lacking. To identify and characterize incident cases of glaucoma and glaucoma-related adverse events (glaucoma + glaucoma suspect) among children in the Infant Aphakia Treatment Study (IATS) by the age of 10.5 years and to determine whether these diagnoses are associated with optic nerve head (ONH) and peripapillary retinal nerve fiber layer (RNFL) assessment. Analysis of a multicenter randomized clinical trial of 114 infants with unilateral congenital cataract who were aged 1 to 6 months at surgery. Data on long-term glaucoma-related status and outcomes were collected when children were 10.5 years old (July 14, 2015, to July 12, 2019) and analyzed from March 30, 2019, to August 6, 2019. Participants were randomized at cataract surgery to either primary intraocular lens (IOL), or aphakia (contact lens [CL]). Standardized definitions of glaucoma and glaucoma suspect were created for IATS and applied for surveillance and diagnosis. Development of glaucoma and glaucoma + glaucoma suspect in operated-on eyes up to age 10.5 years, plus intraocular pressure, axial length, RNFL (by optical coherence tomography), and ONH photographs. In Kaplan-Meier analysis, for all study eyes combined (n = 114), risk of glaucoma after cataract removal rose from 9% (95% CI, 5%-16%) at 1 year, to 17% (95% CI, 11%-25%) at 5 years, to 22% (95% CI, 16%-31%) at 10 years. The risk of glaucoma plus glaucoma suspect diagnosis after cataract removal rose from 12% (95% CI, 7%-20%) at 1 year, to 31% (95% CI, 24%-41%) at 5 years, to 40% (95% CI, 32%-50%) at 10 years. Risk of glaucoma and glaucoma plus glaucoma suspect diagnosis at 10 years was not significantly different between treatment groups. Eyes with glaucoma (compared with eyes with glaucoma suspect or neither) had longer axial length but relatively preserved RNFL and similar ONH appearance and visual acuity at age 10 years. Risk of glaucoma-related adverse events continues to increase with longer follow-up of children following unilateral cataract removal in infancy and is not associated with primary IOL implantation. Development of glaucoma (or glaucoma suspect) after removal of unilateral congenital cataract was not associated with worse visual acuity outcomes at 10 years. ClinicalTrials.gov Identifier: NCT00212134.

Neurofibromatosis Type 1-Associated Optic Pathway Glioma in Children: A Follow-Up of 10 Years or More

This study reports on neurofibromatosis type 1 (NF1)-associated optic pathway gliomas (OPGs) and a follow-up period of at least 10 years in a cohort of children. OPGs are a common manifestation of NF1 and can cause significant visual morbidity. Long-term follow-up in children with NF1-associated OPGs has not been reported previously. Retrospective observational case series. This study included children with a documented follow-up of at least 10 years. Three final outcomes were evaluated: visual acuity (VA) per eye (i.e., in the more severely affected eye), VA per patient (i.e., VA when both eyes were open), and the presence of optic nerve head pallor. A total of 45 children were included, followed for a mean of 14 years (range, 10-21 years). At the end of follow-up, abnormal VA (considered moderate to severe impairment) in the more severely affected eye was present in 36% of the patients and in both eyes in 11%. Optic nerve head pallor of 1 or both nerves was present in 62%. In multivariate analysis, only initial VA and optic nerve head appearance at presentation were found to predict the final outcomes. All patients, except for 1, were asymptomatic at presentation and had normal VA and nerves that appeared normal, preserved their good vision in both eyes. Only 1 patient, who had normal VA and normal appearing nerves at presentation, had moderate to severe VA loss at long term follow-up. In this study, children with NF1-associated OPG whose examination signs and symptoms were normal had a normal initial examination and excellent long-term visual and anatomical outcomes. VA and the appearance of the optic nerve head at presentation predict long-term outcome.

Long-Term Follow-Up of Normal Tension Glaucoma Patients With TBK1 Gene Mutations in One Large Pedigree

To characterize features of glaucoma associated with a TANK binding kinase 1 (TBK1) gene duplication, which is among the most common molecularly defined causes of normal tension glaucoma (NTG). Retrospective observational case series. We conducted a retrospective case series, by reviewing medical records of 7 members of a pedigree with NTG caused by TBK1 gene duplications. Clinical features of these patients at diagnosis, throughout management, and at latest follow-up were identified, including age, intraocular pressure (IOP), central corneal thickness (CCT), optic nerve head appearance, and mean deviation (MD) assessed with Humphrey visual field (HVF) testing protocols. At initial diagnosis, the mean age was 35 ± 7 years, IOP was 16 ± 2.1mm Hg, cup-to-disc (C/D) ratio was 0.9 ± 0.08, and MD assessed via HVF 30-2 and/or 24-2 testing protocols was-9.0 ± 8.9 (range:-1.8 to-27) dB in the 14 study eyes. At initial diagnosis, 4 of 14 eyes (28%) had no visual field defect, 4 (28%) had early visual field defects, and 6 (43%) had severe visual field defects. Patients had a mean follow-up of 21.5 ± 9.0 years and experienced an average reduction of IOP by 28%. Four of 12 eyes (33%) had stable visual fields throughout follow-up, while 8 eyes (67%) had slow-to-moderate progression. The 30-2 and/or 24-2 HVF tests had an average change in MD of-0.53 ± 0.26 dB/year. No eyes had rapid progression with an MD >1.0 dB/year. At final follow-up, the mean IOP was 11.5 ± 2.9, and C/D ratio was 0.94 ± 0.4. At final follow-up, 3 of 14 eyes (21%) had early visual field defects, 4 (29%) had moderate visual field defects, and 7 (50%) had severe visual field defects. Six of 14 eyes (43%) met criteria for legal blindness. We provide the first report of the clinical features and long-term clinical course in a family of NTG patients with TBK1 gene duplications. TBK1-associated glaucoma exhibits classic features of NTG. Patients present with severe disease at a relatively early age and most (67%) have slow-to-moderate progression of their visual field defects. The rate of visual field change appears correlated with the magnitude of IOP, suggesting that it may be advantageous to set extremely low IOP targets for some patients with TBK1-associated glaucoma.

Multi-indices quantification of optic nerve head in fundus image via multitask collaborative learning.

Multi-indices quantification of optic nerve head (ONH), measuring ONH appearance with multiple types of indices simultaneously from fundus images, is the most clinically significant tasks for accurate ONH assessment and ophthalmic disease diagnosis. However, no attempt has been reported due to its challenges of the large variation of fundus appearance across patients, heavy overlap and extremely weak contrast between optic nerve head areas. In this paper, we propose a multitask collaborative learning framework (MCL-Net) for multi-indices ONH quantification. The proposed MCL-Net, a two-branch neural network, first obtains expressive shared and task-specific representations with the backbone network and its two branches; then models the feature exchanges and aggregations between two branches with a well-designed feature interaction module (FIM) to promote each other collaboratively. After that, it estimates multiple types of ONH indices under a multitask ensemble module (MEM) that is capable of learning aggregation of multiple outputs automatically. Therefore, the proposed MCL-Net is consisted of the feature representation, inter-task feature interaction, dual-branch task-specific prediction, and multitask quantification ensemble, which establish an effective framework which takes full advantages of segmentation and estimation tasks for multi-indices ONH quantification. Rather than the low-level feature sharing and individual prediction, the proposed MCL-Net collaboratively learns an optimal combination of shared and task-specific representation, as well as the aggregated prediction, therefore leads to accurate quantification of ONH with multiple types of indices. Experimental results on the dataset of 650 fundus images show that MCL-Net successfully delivers accurate quantification of all the three types of ONH indices, with average mean absolute error of 0.98 ± 0.20, 0.97 ± 0.16, 1.19 ± 0.18, as well as average correlation coefficient of 0.699, 0.708 and 0.691, for diameters, whole areas and regional areas, respectively. In addition, the experiments demonstrate that quantitative indices obtained by our method provide more effective glaucoma diagnosis with AUC of 0.8698. This endows our proposed MCL-Net a great potential in clinical assessment from focal to global for ophthalmic disease diagnosis.

Deep Learning and Glaucoma Specialists: The Relative Importance of Optic Disc Features to Predict Glaucoma Referral in Fundus Photographs

To develop and validate a deep learning (DL) algorithm that predicts referable glaucomatous optic neuropathy (GON) and optic nerve head (ONH) features from color fundus images, to determine the relative importance of these features in referral decisions by glaucoma specialists (GSs) and the algorithm, and to compare the performance of the algorithm with eye care providers. Development and validation of an algorithm. Fundus images from screening programs, studies, and a glaucoma clinic. A DL algorithm was trained using a retrospective dataset of 86 618 images, assessed for glaucomatous ONH features and referable GON (defined as ONH appearance worrisome enough to justify referral for comprehensive examination) by 43 graders. The algorithm was validated using 3 datasets: dataset A (1205 images, 1 image/patient; 18.1% referable), images adjudicated by panels of GSs; dataset B (9642 images, 1 image/patient; 9.2% referable), images from a diabetic teleretinal screening program; and dataset C (346 images, 1 image/patient; 81.7% referable), images from a glaucoma clinic. The algorithm was evaluated using the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity for referable GON and glaucomatous ONH features. The algorithm's AUC for referable GON was 0.945 (95% confidence interval [CI], 0.929-0.960) in dataset A, 0.855 (95% CI, 0.841-0.870) in dataset B, and 0.881 (95% CI, 0.838-0.918) in dataset C. Algorithm AUCs ranged between 0.661 and 0.973 for glaucomatous ONH features. The algorithm showed significantly higher sensitivity than 7 of 10 graders not involved in determining the reference standard, including 2 of 3 GSs, and showed higher specificity than 3 graders (including 1 GS), while remaining comparable to others. For both GSs and the algorithm, the most crucial features related to referable GON were: presence of vertical cup-to-disc ratio of 0.7 or more, neuroretinal rim notching, retinal nerve fiber layer defect, and bared circumlinear vessels. A DL algorithm trained on fundus images alone can detect referable GON with higher sensitivity than and comparable specificity to eye care providers. The algorithm maintained good performance on an independent dataset with diagnoses based on a full glaucoma workup.

The Role of Optical Coherence Tomography in Differentiating Optic Disc Drusen from Optic Disc Edema.

An elevated optic nerve head can be an ominous sign, sometimes signifying an underlying basis for raised intracranial pressure. Alternatively, patients may harbor a different mechanism for this optic nerve head appearance, including optic disc drusen (ODD), which does not confer any life-threatening implications. It is important to refine the approach to distinguishing ODD from papilledema because this is a relatively common, and important, conundrum encountered in clinical practice. Optical coherence tomography (OCT) is a noninvasive, readily accessible, and cost-effective ocular imaging technique that can improve the diagnostic accuracy for detecting ODD; or, instead, increase the index of suspicion for papilledema, thus prompting additional investigations needed to identify (or exclude) potential causes of raised intracranial pressure. In this review, we will discuss the value of OCT in the diagnostic approach to cases of mild optic disc elevation, with acknowledgment of the potential pearls and pitfalls of this imaging technology. In particular, we will emphasize the helpful role OCT can play in differentiating cases of ODD from mild papilledema in the context of idiopathic intracranial hypertension (IIH).

The Peterborough Scheme for Community Specialist Optometrists in Glaucoma: Results of 4 Years of a Two-Tiered Community-Based Assessment and Follow-up Service

Aims: To report on results of an innovative glaucoma shared-care scheme based in Peterborough, UK.Methods: A retrospective review of all new appointments with 11 community-based specialist optometrists in glaucoma (SOG) was conducted. There are two tiers of SOG, whereby tier 2 SOGs have increased levels of autonomy. All optometrist assessments were reviewed by a consultant ophthalmologist, and levels of agreement were calculated for assessment of optic nerve head appearance, Humphrey visual field test interpretation, diagnosis and outcome.Results: 1639 new patients were assessed by SOGs over a 4-year period. The median waiting time for patients from referral to SOG assessment was 0 days (IQR 0–56), and from SOG assessment to consultant review in a virtual clinic was 12 days (IQR 8–18days). After first appointment, over 60% of patients were classified as low-risk and remained within the SOG scheme. Rates of frank disagreement between SOG and consultant regarding diagnosis and proposed outcome were 5.6 and 10.4%, respectively, for tier 2 SOGs and 15.3 and 28.6%, respectively, for tier 1 SOGs.Conclusions: The SOG scheme demonstrates acceptable levels of accuracy between SOG and glaucoma consultant. This scheme allows many stable low-risk patients to remain out of hospital eye department outpatient clinics.

Does normal‐pressure glaucoma and high‐pressure glaucoma differ in the optic nerve head appearance?

AbstractMany studies have been published trying to find out some differences in the phenotype of normal‐pressure glaucoma (NPG) and high‐pressure glaucoma (HPG). The authors of these studies mainly focused on the “vascular signs”, the visual field and the optic nerve head (ONH) appearance of these 2 clinical presentations. However the debate is very controversial and several papers have reported that after all there is no difference in clinical presentation between NPG and HPG. In this review we will detail the pros and cons of each theory and we will provide the physician with useful practical tips leaving him/her with the following questions: Is the limit between NPG and HPG so tight? Can we find specific clinical characteristics of the ONH according to the clinical presentation? Should not we concentrate on the erroneous NPG diagnoses, i.e. the nonglaucomatous optic neuropathies?

Ocular hypertension: general characteristics and estimated cerebrospinal fluid pressure. The Beijing Eye Study 2011.

PurposeTo examine characteristics of ocular hypertensive subjects and potential associations with estimated cerebrospinal fluid pressure (estCSFP).MethodsThe population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years. Ocular hypertension was defined as intraocular pressure (IOP) >21 mmHg, normal optic nerve head appearance and normal retinal nerve fiber layer thickness. IOP was corrected for its dependence on central corneal thickness (CCT) and corneal curvature radius. Estimated CSFP was calculated as CSFP [mmHg] = 0.44×Body Mass Index [kg/m2]+0.16×Diastolic Blood Pressure [mmHg]−0.18×Age [Years]−1.91. Estimated trans-lamina cribrosa pressure difference (estTLCPD) was IOP–estCSFP.ResultsEstCSFP (10.5±3.6 mmHg versus 9.0±3.7 mmHg; P = 0.003) and estTLCPD (12.0±4.4 mmHg versus 5.4±3.8 mmHg; P<0.001) were higher in the ocular hypertensive group than in the normotensive group. In binary regression analysis, ocular hypertension was associated with increased estCSFP (P = 0.03; odds ratio (OR): 1.08; 95% confidence interval (CI): 1.01, 1.17) after adjusting for prevalence of arterial hypertension (P = 0.07; OR: 1.79; 95%CI: 0.96, 3.34), retinal nerve fiber layer thickness (P = 0.03; OR: 0.97; 95%CI: 0.95, 0.997) and blood glucose concentration (P = 0.006; OR: 1.17; 95%CI: 1.04, 1.30).ConclusionsOcular hypertensive subjects (with IOP correction for CCT and corneal curvature) as compared to ocular normotensive subjects had a significantly higher estCSFP in univariate analysis and in multivariate analysis. Despite of a higher estCSFP, estTLCPD was still markedly higher in ocular hypertensive eyes than in ocular normotensive eyes.

Intra-retinal layer segmentation of 3D optical coherence tomography using coarse grained diffusion map.

Optical coherence tomography (OCT) is a powerful and noninvasive method for retinal imaging. In this paper, we introduce a fast segmentation method based on a new variant of spectral graph theory named diffusion maps. The research is performed on spectral domain (SD) OCT images depicting macular and optic nerve head appearance. The presented approach does not require edge-based image information in localizing most of boundaries and relies on regional image texture. Consequently, the proposed method demonstrates robustness in situations of low image contrast or poor layer-to-layer image gradients. Diffusion mapping applied to 2D and 3D OCT datasets is composed of two steps, one for partitioning the data into important and less important sections, and another one for localization of internal layers. In the first step, the pixels/voxels are grouped in rectangular/cubic sets to form a graph node. The weights of the graph are calculated based on geometric distances between pixels/voxels and differences of their mean intensity. The first diffusion map clusters the data into three parts, the second of which is the area of interest. The other two sections are eliminated from the remaining calculations. In the second step, the remaining area is subjected to another diffusion map assessment and the internal layers are localized based on their textural similarities. The proposed method was tested on 23 datasets from two patient groups (glaucoma and normals). The mean unsigned border positioning errors (mean ± SD) was 8.52 ± 3.13 and 7.56 ± 2.95 μm for the 2D and 3D methods, respectively.

Optic nerve head morphology in young patients after antiglaucomatous filtering surgery

To compare the optic nerve head appearance in glaucomatous eyes before and after marked reduction of intraocular pressure (IOP). The hospital-based observational case-series study included selected glaucoma patients for whom optic disc photographs taken before and 1 week to 5 months after surgical reduction of IOP were morphometrically examined. The study included 23 eyes of 16 patients (mean age: 28.7 ± 6.0 years). Mean preoperative IOP was 31.6 ± 7.7 mmHg (22-52 mmHg), and mean IOP drop was 21.5 ± 8.4 mmHg (11-45 mmHg). The horizontal disc diameter decreased significantly (p < 0.001) after surgery, while the vertical disc diameter did not change markedly (p = 0.54). The width of the neuroretinal rim increased significantly in all disc quadrants (all p-values ≤ 0.01), optic cup depth decreased (p < 0.001), and reflectivity of the inner retinal surface increased significantly (p < 0.001). Some eyes showed a pronounced reduction in beta zone of parapapillary atrophy parallel to an increase in horizontal disc diameter, and some eyes showed an enlargement of beta zone parallel to a reduction in horizontal disc diameter. After marked reduction of high IOP, some eyes of young adult patients with glaucoma can show a horizontal shrinkage of the optic nerve head, in addition to a partial restoration of the neuroretinal rim and a flattening of the optic cup. In addition, beta zone of parapapillary atrophy can decrease or increase, complementarily to changes in the horizontal disc diameter. These findings may be of interest for the biomechanics of the optic nerve head and the precision of imaging techniques.