Optic Cup Research Articles

Eye Morphogenesis in Vertebrates.

Proper eye structure is essential for visual function: Multiple essential eye tissues must take shape and assemble into a precise three-dimensional configuration. Accordingly, alterations to eye structure can lead to pathological conditions of visual impairment. Changes in eye shape can also be adaptive over evolutionary time. Eye structure is first established during development with the formation of the optic cup, which contains the neural retina, retinal pigment epithelium, and lens. This crucial yet deceptively simple hemispherical structure lays the foundation for all later elaborations of the eye. Building on descriptions of the embryonic eye that started with hand drawings and micrographs, the field is beginning to identify mechanisms driving dynamic changes in three-dimensional cell and tissue shape. A combination of molecular genetics, imaging, and pharmacological approaches is defining connections among transcription factors, signaling pathways, and the intracellular machinery governing the emergence of this crucial structure.

PKRT-Net: Prior knowledge-based relation transformer network for optic cup and disc segmentation

Glaucoma causes irreversible vision loss, and early detection of glaucoma is essential to protect the vision of patients. The optic cup (OC) and optic disc (OD) are two critical anatomical structures for glaucoma diagnosis. Methods based on convolutional neural networks (CNNs) have been proposed to extract OC and OD, in which OC extraction is very challenging. However, the clinical prior knowledge is not fully utilized in existing CNN methods, which limits the performance of extracting OC and OD. Besides, CNN methods cannot learn long-range semantic information interaction well due to the intrinsic locality of convolution operations. In this paper, we propose a Prior Knowledge-based Relation Transformer Network (PKRT-Net), which employs the clinical prior knowledge to assist OC segmentation and model efficient long-range relation of spatial features by the transformer. PKRT-Net consists of a dual-branch module, a relation transformer fusion module, and a decoder with weighted fusion. Dual-branch module decouples the fundus image into the vessel feature space and general local feature space; the relation transformer fusion module fuses the clinical prior information with local features to obtain more representative features; the weighted fusion module fuses the multi-scale side-outputs from the decoder with the representation of relation transformer module to improve the segmentation performance. We evaluate our proposed PKRT-Net on three public available OC and OD segmentation datasets (i.e., Drishti-GS, RIM-ONE(r3), and REFUGE). The experimental results demonstrate that our proposed PKRT-Net framework achieves state-of-the-art OC and OD segmentation results on these three public datasets.

Towards an extended EfficientNet-based U-Net framework for joint optic disc and cup segmentation in the fundus image

PurposeAutomatic and accurate segmentation of the optic disc (OD) and optic cup (OC) is crucial for clinical glaucoma screening. However, the segmentation accuracy cannot meet the requirements of clinical diagnosis yet. This paper aims to propose a novel joint segmentation framework to improve accuracy. MethodsWe suggested an extended EfficientNet-based U-Net, named EE-UNet. First, we use the EfficientNet to extract distinguishable features under different scales of receptive fields. Second, we employ the Conditional Random Field as a Recurrent Neural Network (CRF-RNN) to extend the U-Net framework, maintaining an end-to-end mode. Third, the Ranger optimizer is suggested for faster and more stable convergence with minimal computational cost. Finally, we designed a multi-label loss function to balance the foreground and background pixels. ResultsExtensive experiments were trained and verified on the datasets REFUGE and GAMMA and tested on Drishti-GS1 and RIM-ONE-v3. The proposed EE-UNet achieved a high DICE score in OD/OC segmentation (0.9624/0.9228, respectively), outperforming the state-of-the-art (SOTA) methods. ConclusionQuantitative and qualitative results verified the superior performance of the proposed method in OC and OD segmentation, thus proving that it can be a promising tool in the early screening of large-scale glaucoma.

Visco-Circumferential-Suture-Trabeculotomy Versus Rigid-Probe Viscotrabeculotomy in Neonatal-Onset Primary Congenital Glaucoma.

Angle procedures are safe and relatively effective for neonatal onset PCG. Watchful delay in intervention to close to the second month of life is helpful in ensuring diagnosis and making surgery more successful and easier. The purpose of this study was to compare the surgical outcomes of visco-circumferential-suture-trabeculotomy (VCST) to rigid-probe double-entry viscotrabeculotomy (DEVT) and rigid-probe single-entry viscotrabeculotomy (SEVT) in infants with neonatal-onset primary congenital glaucoma (PCG). This was a retrospective chart review. Retrospective chart review of 64 eyes of 64 infants with neonatal-onset PCG referred to Mansoura Ophthalmic Center in Mansoura, Egypt between February 2008 and November 2018. Study groups included VCST, DEVT, and SEVT, and follow-up covered 4 postoperative years. Complete (qualified) success was defined as intraocular pressure (IOP) ≤18mmHg and with 35% IOP reduction from baseline without (with) IOP-lowering medications or further surgical interventions, and without any sign of progression in corneal diameter, axial length, or optic disc cupping and without visual devastating complications. The mean±SD age at presentation and at the surgery of the study children was 3.63±1.74 and 55.23±1.60 days, respectively. The mean±SD IOP and cup/disc ratio of all study eyes at presentation and at final follow-up were 34.91±0.82mmHg and 0.70±0.09 and 17.04±0.74mmHg and 0.63±0.08, respectively. Complete success was achieved in 54.5%, 43.5%, and 31.6% in the VCST, DEVT, and SEVT groups, respectively. A self-limited hyphema was the commonest complication in all groups. Angle procedures are safe and marginally effective for the surgical treatment of neonatal-onset PCG, bringing IOP under control for at least 4 years of follow-up. Circumferential trabeculotomy as a first-line treatment has more favorable outcomes than rigid-probe SEVT. Rigid-probe viscotrabeculotomy offers an alternative to the noncompleted circumferential procedure.

PY-Net: Rethinking segmentation frameworks with dense pyramidal operations for optic disc and cup segmentation from retinal fundus images

Glaucoma is one of the leading causes of irreversible blindness across the globe. Early diagnosis is therefore essential for the provision of timely treatments and reducing the loss of vision. From the retinal fundus images, the calculation of the cup to disc ratio (CDR) is an efficient indicator to distinguish between glaucomatous and non-glaucomatous cases. Therefore, precise segmentation of optic disc and cup from the retinal images are important steps for improved diagnosis of the disease. This paper presents a robust segmentation pipeline for optic disc and cup segmentation utilizing the U-Net architecture. In the upsampling half of the model, a spatial pyramid based decoder cascaded with an intermediate decoder is introduced. To incorporate channel-wise attention throughout the framework squeeze and excite blocks are incorporated. To enhance the relevant spatial features in the feature representations of the fundus images, spatial attention module is utilized. Furthermore to achieve multi-scale context extraction modified receptive field blocks (MRFB) are added to the encoding layers of the network. In addition, the MRFBs are also introduced in the auxiliary decoder for fine-tuning of the feature representation. The performance of the proposed model has been evaluated on three publicly available retinal fundus databases, DRISHTI-GS, RIM-ONE, and REFUGE and the model has achieved a dice score of 97.10, 96.12, 96.48 respectively on the optic disc and 93.38, 92.92, 93.85 on optic cup segmentation, outperforming the state-of-the-art methods.

Joint optic disc and cup segmentation based on elliptical-like morphological feature and spatial geometry constraint

Glaucoma is a chronic degenerative disease that is the second leading cause of irreversible blindness worldwide. For a precise and automatic screening of glaucoma, detecting the optic disc and cup precisely is significant. In this paper, combining the elliptical-like morphological features of the disc and cup, we reformulate the segmentation task from a perspective of ellipse detection to explicitly segment and directly get the glaucoma screening indicator. We detect the minimum bounding boxes of ellipses firstly, and then learn the ellipse parameters of these regions to achieve optic disc and cup segmentation. Considering the spatial geometry prior knowledge that the cup should be within the disc region, Paired-Box RPN is introduced to simultaneously detect the disc and cup coupled. In addition, boundary attention module is introduced to use edges of the disc and cup as an important guide for context aggregation to improve the accuracy. Comprehensive experiments clearly show that our method outperforms the state-of-the-art methods for optic disc and cup segmentation. Simultaneously, the proposed method also obtains the good glaucoma screening performance with calculated vCDR value. Joint optic disc and cup segmentation, which utilizes the elliptical-like morphological features and spatial geometry constraint, could improve the performance of optic disc and cup segmentation.

Combined trabeculotomy-trabeculectomy for glaucoma after congenital cataract surgery: long-term results

ObjectifNotre étude présente les résultats à long terme (> 5 ans) de la chirurgie du glaucome faisant suite à une chirurgie de la cataracte congénitale. NatureÉtude rétrospective. MéthodesIl s'agit d'une revue de synthèse des dossiers médicaux de tous les enfants qui ont fait l'objet, entre 2005 et 2014, d'une intervention en raison d'un glaucome après avoir subi une chirurgie de la cataracte congénitale au service d'ophtalmologie pédiatrique du département d'ophtalmologie de l'Alexandria Main University Hospital (Alexandrie, Égypte) et pour lesquels on dispose d'un suivi à 5 ans. Les données démographiques, cliniques et chirurgicales ont été tirées des dossiers médicaux. La réussite reposait sur la stabilité et/ou le rétablissement de l'excavation du nerf optique comparativement à ce qui a été observé lors de la visite initiale et, en l'absence de cette donnée, sur une pression intraoculaire (PIO) inférieure à la PIO initiale et une PIO inférieure à 16 mm Hg avec (réussite mitigée) ou sans (réussite complète) collyre antiglaucomateux. RésultatsLes dossiers médicaux de 48 enfants ont été passés en revue. On disposait des données de suivi pendant au moins 5 ans pour 32 yeux de 24 enfants, qui ont donc été inclus dans l’étude. L’âge moyen (± é.-t.) des enfants de l’étude était de 11,6 ± 11,3 mois (fourchette : 3,2–52,0 mois) lors de l'examen initial, et la durée moyenne du suivi (± é.-t.) était de 105,5 ± 31,4 mois (fourchette : 60–156 mois). Sur le total des 47 chirurgies du glaucome, une technique reposant à la fois sur une chirurgie de l'angle et une chirurgie filtrante avec antimétabolite était l'intervention le plus souvent réalisée (n = 30; 63,8 %). Les pourcentages annuels de réussite de la cinquième à la treizième année après l'intervention se chiffraient respectivement comme suit : 69,6 %; 68,8 %; 77,8 %; 50,0 %; 71,4 %; 60,0 %; 50,0 %; 83,3 % et 50,0 %. ConclusionsLa chirurgie du glaucome réalisée après une chirurgie de la cataracte congénitale demeure sûre, et son efficacité s'est maintenue pendant les 13 années suivantes.

Technical difficulties of adequate assessment of intraocular pressure in a patient with glaucoma in the long term after corneal refractive surgery (clinical case)

PURPOSE. To demonstrate a clinical case involving difficulties in adequate assessment of intraocular pressure (IOP) in a patient with glaucoma in the long term after LASIK.METHODS. The study describes the case of patient M. of 58 years old with complaints about decreased distance vision in the right eye during the last year. In 2004 the patient underwent LASIK for moderate myopia. In 2018, asymmetry in the parameters of optic nerve head (size of the optic cup to the optic disc ratio (C/D ratio) was revealed: in the right eye — up to 0.7, narrowing of the visual field from nasal to fixation point; in the left eye — 0.5, visual fields without abnormalities. The IOP measured using the Maklakov method in both eyes corresponded to the average statistical norm — 22 mm Hg. The following diagnosis was established: IIA primary open-angle glaucoma in the right eye, IA primary open-angle glaucoma in the left eye. One-time instillations of latanoprost 0.005% eye drops solution was indicated for both eyes. In subsequent years the IOP was 18–20 mm Hg. After 4 years, the IOP according to the Maklakov method: OD — 18 mm Hg; OS — 21 mm Hg (on the hypotensive regimen — instillations of latanoprost 0.005% eye drops solution). In the right eye: C/D ratio 0.85–0.9 with absolute scotoma in the Bjerrum area 5–15° from fixation; in the left eye: C/D ratio 0.9 with neuro retinal rim loss from below, with absolute scotoma in the blind spot area. The stages of primary open-angle glaucoma were ascertained: IIIA in the right eye, IIA in the left eye.RESULTS. Selective laser trabeculoplasty was performed. Brimonidine 0.1% solution was added due to the lack of complete stabilization of the IOP level on a single instillation of latanoprost 0.005%, after that IOP decreased to 19 mm Hg in both eyes.CONCLUSION. It is necessary to carefully assess the condition of the structures of the optic nerve head in patients after LASIK, regardless of the statistically normal IOP values.

Glaucoma Detection Using Fundus Images of the Retina

In the paper that we are proposing we make use of the image processing technique that can be further used to detect or predict whether the eye is glaucomatic which leads to increase in the size of the optic cup in turn affecting the optic disc. Glaucoma being the second major reason for blindness was very difficult to detect in the early stages. Here in this paper, we make use of the retinal fundus images and glaucoma is being detected using the features that we extract from the fundus images. The first feature that we extract includes one of the basic physiological parameters which is the Cup to Disc ratio (CDR) and the second feature that we extract is the neuro retinal rim which has the inferior, superior, nasal and the temporal quadrants often called the ISNT quadrants which can be used to detect glaucoma in the fundus image of the eye.

The Extent of Silicone Oil Emulsification Revealed by Ultra-wide-field Fundus Photography and Optical Coherence Tomography

Purpose: We assessed the extent of silicone oil (SO) emulsification using ultra-wide-field fundus photography (wFP) and the reflective ratios of swept-source optical coherence tomography (SS-OCT).Methods: We retrospectively enrolled 51 eyes of 51 patients who underwent intravitreal SO tamponade with vitrectomy. Two weeks after SO tamponade and immediately before SO removal, ultra-wide-field fundus photography and SS-OCT were performed. Based on the numbers of emulsified droplets in the ultra-wide-field fundus photographs, SO emulsification was qualitatively graded from 0 to 4. Reflective ratios were calculated by dividing the OCT reflectivity of the optic cup by the OCT reflectivity of SO near the retinal surface. We analyzed the changes in the SO emulsification grade and the reflective ratio over time (RR2/RR1).Results: The SO emulsification grade revealed by ultra-wide-field fundus photography was 2.12 ± 1.29, and the mean SS-OCT RR2/RR1 value was 1.14 ± 0.22. A longer duration of SO tamponade was associated with a higher emulsification grade on ultra-wide-field fundus photography and an increase in the RR2/RR1 value (both <i>p</i> < 0.01). We found a significant correlation between the SO emulsification grade on ultra-wide-field fundus photography and the SS-OCT RR2/RR1 (<i>p</i> = 0.028).Conclusions: Ultra-wide-field fundus photography and SS-OCT can be used to determine objectively the extent of SO emulsification; this may indicate the appropriate SO removal time any complication.

A Practical Guide to Measuring Optic Disc Size and its Clinical Correlation in Diagnosing Glaucoma for the Eye Care Professional

This study examines the connection between glaucoma and the optic disc, cup, and neuroretinal rim size. The use of a slit-lamp and funduscopy lens as a technique for determining and estimating the optic disc size is particularly emphasized. Through this study, a clinical manual for working clinicians will be developed by summarizing this information and making it easily accessible for in-office use. PubMed, Science Direct, Ovid, Medline journals, and inter-library journals were used to find papers and abstracts of relevant studies for this review. The most common search terms were: procedures for assessing optic disc size, variance in optic disc size between populations, and ophthalmoscopic methods for measuring optic discs. The search period spanned 2020 to 2022. The following criteria were used to determine whether an article should be included or excluded: a critical evaluation of the various methods used to measure the optic disc, the significance of including population-specific variations in the size of the optic disc, and justifications for the relative risk of glaucoma associated with the size of both the optic disc and the optic cup. According to numerous studies, a slit lamp and funduscopy lens can be used to estimate the size of the optic disc. Additionally, this review discovered a weak association between measures taken at a slit lamp and those taken with more exact office tools, including fundus photography. Using fundoscopic technologies is an effective and affordable method for measuring the optic nerve head while retaining a high level of accuracy. These dimensions can be used to divide the sizes of optic discs into three groups: small, average, and large.

EARDS: EfficientNet and attention-based residual depth-wise separable convolution for joint OD and OC segmentation.

Glaucoma is the leading cause of irreversible vision loss. Accurate Optic Disc (OD) and Optic Cup (OC) segmentation is beneficial for glaucoma diagnosis. In recent years, deep learning has achieved remarkable performance in OD and OC segmentation. However, OC segmentation is more challenging than OD segmentation due to its large shape variability and cryptic boundaries that leads to performance degradation when applying the deep learning models to segment OC. Moreover, the OD and OC are segmented independently, or pre-requirement is necessary to extract the OD centered region with pre-processing procedures. In this paper, we suggest a one-stage network named EfficientNet and Attention-based Residual Depth-wise Separable Convolution (EARDS) for joint OD and OC segmentation. In EARDS, EfficientNet-b0 is regarded as an encoder to capture more effective boundary representations. To suppress irrelevant regions and highlight features of fine OD and OC regions, Attention Gate (AG) is incorporated into the skip connection. Also, Residual Depth-wise Separable Convolution (RDSC) block is developed to improve the segmentation performance and computational efficiency. Further, a novel decoder network is proposed by combining AG, RDSC block and Batch Normalization (BN) layer, which is utilized to eliminate the vanishing gradient problem and accelerate the convergence speed. Finally, the focal loss and dice loss as a weighted combination is designed to guide the network for accurate OD and OC segmentation. Extensive experimental results on the Drishti-GS and REFUGE datasets indicate that the proposed EARDS outperforms the state-of-the-art approaches. The code is available at https://github.com/M4cheal/EARDS.

Commentary: Reliability, repeatability, and accuracy of Sirius topographer in assessing anterior segment morphology following laser peripheral iridotomy in primary angle-closure disease.

Commentary: Reliability, repeatability, and accuracy of Sirius topographer in assessing anterior segment morphology following laser peripheral iridotomy in primary angle-closure disease.

Clinical identification of optic disk vascular alteration in glaucoma.

Several characteristic vascular changes can be observed in the glaucomatous eyes, including changes in the vessel configuration and caliber, presence of collateral vessel on disk, and disk hemorrhage. This video describes characteristic vascular changes in the optic nerve head, which can be observed on clinical examination in the glaucomatous eyes, and useful teaching points to identify the same. In glaucoma, as the optic cup enlarges, the normal pattern and course of retinal vessels on the optic disk are altered and show characteristic changes. Identification of these changes provides a clue to the presence of cupping. In this video, the vascular changes and its identification in the glaucomatous disc are described, which would be useful to the residents. https://youtu.be/2eINumBx33E.

Optical Cup and Disc Segmentation using Deep Learning Technique for Glaucoma Detection

The optic nerve damaging condition called Glaucoma. This disease is increment at an alarming rate. By the end of the 2044 there is possibility that across 111.8 million populations will be influenced by glaucoma. It is a neurodegenerative disease. If intravascular pressure is increases, optic nerve of the eye gets damage. This damage may cause permanent or total blindness in person. The Glaucoma is examined by an experienced ophthalmologist on the retinal part of the eye. This process required excessive equipment, experienced medical practitioners and also it take more time to work out manually. After considering this problem there is an extreme requirement of developing an automatic system which will effectively and automatically work properly in lack of any professional doctor and it should also take less time. Lots of different parameters are available to detect glaucoma but thebest parameter is to find out optical cup-to-disc-ratio. To increase or to enhance the precision and accuracy of the result, cup to disc value is needed to find CDR value. In order to detect glaucoma, automatic separation of the OC and DC is very essential to avoid any error. We use deeplabv3 architecture to perform segmentation of optic disc and cup and classification is done using ensemble machine learning. This proposes research achieve intersection over union (IOU) scores, 0.9423 for optic disc and 0.9310 for optic cup. We perform testing on globally accessible data-sets i.e. DRISHTI, ORIGA, and RIMONE with accuracy of 93%, 91% and 92% respectively

Better feature extraction using multi-encoder convolutional neural networks for optic cup segmentation from digital fundus images

Better feature extraction using multi-encoder convolutional neural networks for optic cup segmentation from digital fundus images

Chákṣu: A glaucoma specific fundus image database

We introduce Chákṣu–a retinal fundus image database for the evaluation of computer-assisted glaucoma prescreening techniques. The database contains 1345 color fundus images acquired using three brands of commercially available fundus cameras. Each image is provided with the outlines for the optic disc (OD) and optic cup (OC) using smooth closed contours and a decision of normal versus glaucomatous by five expert ophthalmologists. In addition, segmentation ground-truths of the OD and OC are provided by fusing the expert annotations using the mean, median, majority, and Simultaneous Truth and Performance Level Estimation (STAPLE) algorithm. The performance indices show that the ground-truth agreement with the experts is the best with STAPLE algorithm, followed by majority, median, and mean. The vertical, horizontal, and area cup-to-disc ratios are provided based on the expert annotations. Image-wise glaucoma decisions are also provided based on majority voting among the experts. Chákṣu is the largest Indian-ethnicity-specific fundus image database with expert annotations and would aid in the development of artificial intelligence based glaucoma diagnostics.

Protocol for lens removal in embryonic fish and its application on the developmental effects of eye regression

The lens plays a central role in the development of the optic cup. In fish, regression of the eye early in development affects the development of the craniofacial skeleton, the size of the olfactory pits, the optic nerve, and the tectum. Lens removal further affects olfaction, prey capture, and aggression. The similarity of the fish eye to other vertebrates is the basis for its use as an excellent animal model of human defects. Questions regarding the effects of eye regression are specifically well-suited to be addressed by using fish from the genus Astyanax. The species has two morphs; an eyeless cave morph and an eyed, surface morph. In the cavefish, a lens initially develops in embryos, but then degenerates by apoptosis. The cavefish retina is subsequently disorganized, degenerates, and retinal growth is arrested. The same effect is observed in surface fish when the lens is removed or exchanged for a cavefish lens. While studies can greatly benefit from a control group of surface fish with regressed eyes brought through lensectomies, few studies include them because of technical difficulties and the low survivorship of embryos that undergo this procedure. Here we describe a technique with significant modification for improvement for conducting lensectomy in one-day-old Astyanax and other fish, including zebrafish. Yields of up to 30 live embryos were obtained using this technique from a single spawn, thus enabling studies that require large sample sizes.

Dual Consistency Enabled Weakly and Semi-Supervised Optic Disc and Cup Segmentation with Dual Adaptive Graph Convolutional Networks.

Glaucoma is a progressive eye disease that results in permanent vision loss, and the vertical cup to disc ratio (vCDR) in colour fundus images is essential in glaucoma screening and assessment. Previous fully supervised convolution neural networks segment the optic disc (OD) and optic cup (OC) from color fundus images and then calculate the vCDR offline. However, they rely on a large set of labeled masks for training, which is expensive and time-consuming to acquire. To address this, we propose a weakly and semi-supervised graph-based network that investigates geometric associations and domain knowledge between segmentation probability maps (PM), modified signed distance function representations (mSDF), and boundary region of interest characteristics (B-ROI) in three aspects. Firstly, we propose a novel Dual Adaptive Graph Convolutional Network (DAGCN) to reason the long-range features of the PM and the mSDF w.r.t. the regional uniformity. Secondly, we propose a dual consistency regularization-based semi-supervised learning paradigm. The regional consistency between the PM and the mSDF, and the marginal consistency between the derived B-ROI from each of them boost the proposed model's performance due to the inherent geometric associations. Thirdly, we exploit the task-specific domain knowledge via the oval shapes of OD & OC, where a differentiable vCDR estimating layer is proposed. Furthermore, without additional annotations, the supervision on vCDR serves as weakly-supervisions for segmentation tasks. Experiments on six large-scale datasets demonstrate our model's superior performance on OD & OC segmentation and vCDR estimation. The implementation code has been made available 1.

Acquired Lens Zonular Loss with Bean Pot Optic Disc Cupping in Congenital Glaucoma

Acquired Lens Zonular Loss with Bean Pot Optic Disc Cupping in Congenital Glaucoma