Atlas-based score for automatic glaucoma risk stratification.

Glaucoma is a disease that affects the optic nerve and can lead to blindness. The cup-to-disc ratio (CDR) measurement is one of the key clinical indicators for glaucoma assessment. However, the CDR only evaluates the relative sizes of the cup and optic disc (OD) via their diameters, and does not characterize local morphological changes that can inform clinicians on early signs of glaucoma. In this work, we propose a novel glaucoma score based on a statistical atlas framework that automatically quantifies the deformations of the OD region induced by glaucoma. A deep-learning approach is first used to segment the optic cup with a dedicated atlas-based data augmentation strategy. The segmented OD region (disc, cup and vessels) is then registered to the statistical OD atlas and the deformation is projected onto the atlas eigenvectors. The atlas glaucoma score (AGS) is then obtained by a linear combination of the principal modes of deformation of the atlas with linear discriminant analysis. The AGS performs better than the CDR on the three datasets used for evaluation, including RIM-ONE and ORIGA650. Compared to the CDR measurement, which yields an area under the ROC curve (AUC) of 91.4% using the expert segmentations, the AGS achieves an AUC of 98.2%. Our novel glaucoma score captures more complex deformations within the optic disc region than the CDR can. Such morphological changes are the first cue of glaucoma onset, before the visual field is affected. The proposed approach can thus significantly improve early detection of glaucoma.

Joint segmentation and classification of retinal arteries/veins from fundus images.

OBJECTIVE: Automatic artery/vein (A/V) segmentation from fundus images is required to track blood vessel changes occurring with many pathologies including retinopathy and cardiovascular pathologies. One of the clinical measures that quantifies vessel changes is the arterio-venous ratio (AVR) which represents the ratio between artery and vein diameters. This measure significantly depends on the accuracy of vessel segmentation and classification into arteries and veins. This paper proposes a fast, novel method for semantic A/V segmentation combining deep learning and graph propagation. METHODS: A convolutional neural network (CNN) is proposed to jointly segment and classify vessels into arteries and veins. The initial CNN labeling is propagated through a graph representation of the retinal vasculature, whose nodes are defined as the vessel branches and edges are weighted by the cost of linking pairs of branches. To efficiently propagate the labels, the graph is simplified into its minimum spanning tree. RESULTS: The method achieves an accuracy of 94.8% for vessels segmentation. The A/V classification achieves a specificity of 92.9% with a sensitivity of 93.7% on the CT-DRIVE database compared to the state-of-the-art-specificity and sensitivity, both of 91.7%. CONCLUSION: The results show that our method outperforms the leading previous works on a public dataset for A/V classification and is by far the fastest. SIGNIFICANCE: The proposed global AVR calculated on the whole fundus image using our automatic A/V segmentation method can better track vessel changes associated to diabetic retinopathy than the standard local AVR calculated only around the optic disc.

Statistical atlas-based descriptor for an early detection of optic disc abnormalities.

Optic disc (OD) appearance in fundus images is one of the clinical indicators considered in the assessment of retinal diseases such as glaucoma. The cup-to-disc ratio (CDR) is the most common clinical measurement used to characterize glaucoma. However, the CDR only evaluates the relative sizes of the cup and the OD via their diameters. We propose to construct an atlas-based shape descriptor (ASD) to statistically characterize the geometric deformations of the OD shape and of the blood vessels' configuration inside the OD region. A local representation of the OD region is proposed to construct a well-defined statistical atlas using nonlinear registration and statistical analysis of deformation fields. The shape descriptor is defined as being composed of several statistical measures from the atlas. Analysis of the average model and its principal modes of deformation are performed on a healthy population. The components of the ASD show a significant difference between pathological and healthy ODs. We show that the ASD is able to characterize healthy and glaucomatous OD regions. The deviation map extracted from the atlas can be used to assist clinicians in an early detection of deformation abnormalities in the OD region.

Genotype and Phenotype Studies in Autosomal Dominant Retinitis Pigmentosa (adRP) of the French Canadian Founder Population.

PURPOSE: The French Canadian population of Quebec is a unique, well-known founder population with religious, linguistic, and geographic isolation. The genetics of retinitis pigmentosa (RP) in Quebec is not well studied thus far. The purpose of our study was to establish the genetic architecture of autosomal dominant RP (adRP) and to characterize the phenotypes associated with new adRP mutations in Quebec. METHODS: Sanger sequencing of the commonly mutated currently known adRP genes was performed in a clinically well-characterized cohort of 60 adRP French Canadian families. Phenotypes were analyzed by projected visual acuity (best corrected), Goldmann visual fields, optical coherence tomography (OCT), fundus autofluorescence (FAF), and ERG. The potential effect of the novel mutations was assessed using in silico bioinformatic tools. The pathogenicity of all variants was then confirmed by segregation analysis within the families, when available. RESULTS: We identified the causal mutation/gene in 24 of our adRP families, as 24 (40%) of 60 patients had adRP mutations in six known adRP genes. Eleven (46%) of these mutations were in RHO, four mutations (17%) were found in SNRNP200, three mutations (12.5%) in PRPH2/RDS, three mutations (12.5%) in TOPORS, two mutations (8%) in PRPF31, and one mutation (4%) in IMPDH1. Four mutations were novel. We identified new mutations in RHO (p.S270I), PRPF31 (p.R288W), IMPDH1 (p.Q318H), and TOPORS (p.H889R); the rest were previously reported. We present the genotype-phenotype characteristics of the four novel missense mutations. CONCLUSIONS: This is the first large screening of adRP genes in the founder population of Quebec. Our prevalence of known adRP genes is 40% in the French Canadian population, which is lower than in other adRP populations around the world, illustrating the uniqueness of the French Canadian population. Our findings are crucial in expanding the current understanding of the genotypic-phenotypic spectrum of RP and documenting the genetic architecture of our founder population.

Superficial epithelioma with sebaceous differentiation involving the eyelid: a case report.

INTRODUCTION: Superficial epithelioma with sebaceous differentiation is a rare benign epithelial neoplasm. It usually involves the head, neck or the back of a middle-age person. To the best of our knowledge, two ocular cases have been reported in the literature. CASE PRESENTATION: A 46-year-old man of Italian descent, with a known history of testicular seminoma treated by orchiectomy with chemotherapy and radiotherapy, presented with a tan-colored lesion measuring 4mm in diameter in his right upper lid that had been growing over 10 months. It was clinically diagnosed as papilloma. An excisional biopsy was done. On histological examination, the lesion was a well-circumscribed and sharply demarcated epithelial tumor attached to the overlying epidermis and characterized by plate-like proliferation of basaloid to squamous cells with clusters of mature sebaceous cells and foci of ductal differentiation. After a follow-up period of 5 months, no recurrence of the lesion has been documented. CONCLUSIONS: Superficial epithelioma with sebaceous differentiation is part of the differential diagnoses of eyelid lesions. Arguments in the literature about the correct nomenclature of superficial epithelioma with sebaceous differentiation have resulted in under-diagnosed cases. The benign histological features and the lack of recurrence support its benign nature. Although no clear association has linked superficial epithelioma with sebaceous differentiation with Muir-Torre syndrome, further clinical correlation and close follow up for patients are recommended.

The use of intraoperative fluoroscopy as an aid for removal of radiopaque intraorbital foreign bodies.

Two patients with orbital trauma and intraorbital foreign bodies, as seen on a computed tomography scan, were taken to the operating room to rule out occult ruptured globe with possible foreign body removal. The C-arm fluoroscopic unit was employed to obtain real-time images of the foreign body's location in relation to the surgeon's dissection tools and the foreign body was extracted with minimal dissection and operating time. When removal of a foreign body is warranted, intraoperative fluoroscopy can help reduce surgical time and orbital manipulation.

Intralesional injection of Tisseel fibrin glue for resection of lymphangiomas and other thin-walled orbital cysts.

PURPOSE: Surgical removal of orbital lymphangiomas is often difficult because the capsule of these lesions is fragile, and, once violated, it tends to collapse, making identification of residual tumor difficult and dissection often incomplete. A surgical technique combining partial controlled decompression of the lesion with intralesional injection of Tisseel fibrin glue is evaluated to determine its effectiveness in resecting the lesion and preventing recurrences. METHODS: This is a retrospective interventional case series. Three young patients, two with lymphangiomas and one with congenital hydrocystoma, underwent surgical resection of their thin-walled cystic lesions of the orbit with the use of intralesional injection of Tisseel fibrin glue. Resolution of the signs and symptoms, complications of the surgery, and recurrence of bleeding are the parameters studied. RESULTS: All 3 patients had improvement of their signs and symptoms. None had complications related to the surgery, and no recurrence of bleeding occurred during the follow-up period. CONCLUSIONS: Our study suggests that this surgical technique with intralesional injection of Tisseel fibrin glue is an effective treatment modality for the resection of lymphangiomas and other orbital thin-walled cystic lesions.