A new computer-aided diagnosis tool based on deep learning methods for automatic detection of retinal disorders from OCT images

PURPOSE

Early detection of retinal disorders using optical coherence tomography (OCT) images can prevent vision loss. Since manual screening can be time-consuming, tedious, and fallible, we present a reliable computer-aided diagnosis (CAD) software based on deep learning. Also, we made efforts to increase the interpretability of the deep learning methods, overcome their vague and black box nature, and also understand their behavior in the diagnosis.

METHODS

We propose a novel method to improve the interpretability of the used deep neural network by embedding the rich semantic information of abnormal areas based on the ophthalmologists' interpretations and medical descriptions in the OCT images. Finally, we trained the classification network on a small subset of the online publicly available University of California San Diego (UCSD) dataset with an overall of 29,800 OCT images.

RESULTS

The experimental results on the 1000 test OCT images show that the proposed method achieves the overall precision, accuracy, sensitivity, and f1-score of 97.6%, 97.6%, 97.6%, and 97.59%, respectively. Also, the heat map images provide a clear region of interest which indicates that the interpretability of the proposed method is increased dramatically.

CONCLUSION

The proposed software can help ophthalmologists in providing a second opinion to make a decision, and primitive automated diagnoses of retinal diseases and even it can be used as a screening tool, in eye clinics. Also, the improvement of the interpretability of the proposed method causes to increase in the model generalization, and therefore, it will work properly on a wide range of other OCT datasets.

Pattern electroretinography response in amblyopic adults

INTRODUCTION

Amblyopia is generally a unilateral disorder, defined by at least a difference of two lines of visual acuity between both eyes with the best-corrected visual acuity, a decrease in contrast sensitivity, and a decrease in stereopsis. Pattern electroretinogram (PERG) is a noninvasive technique that provides a retinal biopotential and is a highly sensitive indicator of changes in the macular area. Our aim was to evaluate if there are differences in the retinal response of an amblyopic eye compared with a normal eye (NE).

METHODS

We evaluated twenty-four adult volunteers, twelve amblyopes (mean 43.42 ± 12.72 years old), and twelve subjects with NE (mean 35.58 ± 12.85 years old). None of the subjects in the two groups had comorbidities. A complete optometric examination was performed including parameters such as visual acuity (VA) by far and near with ETDRS chart, eye alignment with cover test, and evaluation of retinal cells response with PERG.

RESULTS

The refractive error found in the NE group of subjects had a mean of - 0.95 ± 1.65D, while the amblyopic group showed a mean of - 2.03 ± 4.29D. The VA in amblyopic eyes had a mean of 0.38 ± 0.20 logMAR. Analyzing PERG data, we observed significant differences in the P50-N95 amplitudes of the amblyopic group compared with the NE group (p < 0.0001-amblyopic eye vs. NE; p = 0.039-fellow eye vs. NE).

DISCUSSION

These findings suggest that amblyopic patients may also present other impairments beyond the visual cortex. PERGs seem to be an important complementary examination in the diagnosis of other impairments in amblyopia.

Electronic medical records driven big data analytics in retinal diseases, report number 1: non-oncological retinal diseases in children and adolescents in India

PURPOSE

To describe the spectrum and demographic distribution of non-oncological retinal diseases in children and adolescents presenting to a multi-tier ophthalmic hospital network in India.

METHODS

This is a cross-sectional hospital-based retrospective study over nine years (March 2011-March 2020) from a pyramidal eye care network in India. The analysis included 477,954 new patients (0-21 years), collected from an International Classification of Diseases (ICD) coded electronic medical record (EMR) system. Patients with a clinical diagnosis of retinal disease (non-oncological) in at least one eye were included. Age-wise distribution of these diseases in children and adolescents was analysed.

RESULTS

In the study, 8.44% (n = 40,341) of new patients were diagnosed with non-oncological retinal pathology in at least one eye. The age group-specific distribution of retinal diseases was 47.4%, 11. 8%, 5.9%, 5.9%, 6.4%, 7.6% in infants (< 1 year), toddlers (1-2 years), early childhood (3-5 years), middle childhood (6-11 years), early adolescents (12-18 years) and late adolescents (18-21 years), respectively. 60% were male, and 70% had bilateral disease. The mean age was 9.46 ± 7.52 years. The common retinal disorders were retinopathy of prematurity (ROP, 30.5%), retinal dystrophy (19.5%; most commonly, retinitis pigmentosa), and retinal detachment (16.4%). Four-fifth of the eyes had moderate to severe visual impairment. Nearly one-sixth of patients needed low vision and rehabilitative services, and about 1 in 10 patients required surgical intervention (n = 5960, 8.6%).

CONCLUSION AND RELEVANCE

About 1 in 10 children and adolescents seeking eye care in our cohort had non-oncological retinal diseases; the common ones were ROP (in infants) and retinitis pigmentosa (in adolescents). This information would help future strategic planning of eye health care in the institution in pediatric and adolescent age groups.

Update of application of olfactory ensheathing cells and stem cells/exosomes in the treatment of retinal disorders

Age-related macular degeneration, diabetic retinopathy, retinitis pigmentosa and other retinal disorders are the main causes of visual impairment worldwide. In the past, these retinal diseases, especially dry age-related macular degeneration, proliferative diabetic retinopathy and retinitis pigmentosa, were treated with traditional surgery and drugs. However, the effect was moderate. In recent years, researchers have used embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, olfactory ensheathing cells and other stem cells to conduct experiments and found that stem cells can inhibit inflammation, regulate immune response, secrete neurotrophic factors, and differentiate into retinal cells to replace and promote restoration of the damaged parts. These stem cells have the potential to treat retinal diseases. Whether it is in animal experiments or clinical trials, the increase in the number of retinal cells, maintenance of function and improvement of visual function all reflect the advanced of stem cells to treat retinal diseases, but its risk preserves the donor's hidden pathogenic genes, immune rejection and tumorigenicity. With the development of exosomes study, researchers have discovered that exosomes come from a wide range of sources and can be secreted by almost all types of cells. Using exosomes with stem cell to treat retinal diseases is more effective than using stem cells alone. This review article summarizes the recent advances in the application of olfactory ensheathing cells and stem cells/exosomes in the treatment of retinal disorders.

Prevalence of age-related macular degeneration among optometric telemedicine users in Spain: a retrospective nationwide population-based study

PURPOSE

To evaluate the prevalence of AMD among optometric telemedicine users in Spain and to identify risk factors.

METHODS

Retrospective analysis of a nationwide database conducted on subjects attending to optometry centers, between January 2013 and December 2019. Fundus photographs were performed by optometrists, using non-mydriatic cameras, and evaluated by a group of 12 retina specialists.

RESULTS

Among the 119,877 subjects included, the overall prevalence of AMD was 7.6%. The prevalence of early, intermediate, and advanced AMD was 2.9%, 2.7%, and 2.0%, respectively. Of the 9129 AMD subjects, 1161 (12.7%) had geographic atrophy, and 1089 (11.9%) had neovascular AMD, either scar (4.5%) or exudative (7.4%). There was a significant association between AMD and age (per year older, adjusted odds ratio, OR 1.116; 95% CI 1.114 to 1.119, p<0.0001). Women had higher prevalence (adjusted OR 1.17; 95% CI 1.12 to 1.23, p<0.0001). Every diopter (spherical equivalent) of progress toward hyperopia was associated with a significant increase in early AMD prevalence (adjusted OR 1.02, 95 CI 1.01 to 1.04, p=0.0074). Presence of diabetes was associated with a lower AMD prevalence (p<0.0001).

CONCLUSIONS

The prevalence of AMD (any eye and any severity) was 7.6%, with a prevalence of advanced AMD of 2.0%. Older age and women were significantly associated with a higher prevalence of AMD, whereas myopia and presence of diabetes were associated with significantly lower odds of any AMD.

NGF in Inflammatory and Neurodegenerative Diseases of the Eye: New Findings Supporting Neuroprotection and Proper Tissue Remodeling in Vitreoretinal Disorders

Nerve growth factor (NGF) plays a crucial role in retinal disorders, as suggested by in vitro/in vivo models. The major effect embraces the neuroprotective activity on retinal ganglion cells (RGCs) undergoing degeneration, as observed in experimental diabetic retinopathy, age-related and diabetic macular degeneration, and some vitreoretinal diseases. Focused experiments suggested that locally applied NGF (intravitreal delivery) not only allowed the counteraction of RGC degeneration but also provided data for a whole retina restoration. The currently available retinal microsurgery allows the collection of human aqueous and more interesting vitreous (vitreal reflux) humors. The recent biomolecular analysis highlights the possibility to identify disease-associated biomarkers and allow the monitoring of retinal impairments with sustain to the retinal imaging. Coupled to other soluble mediators, NGF has been quantified in aqueous (slightly expressed) from diabetic retinopathy-suffering patients (cataract surgery) and vitreal reflux (significantly impaired) of diabetic macular degeneration-suffering patients (intravitreal surgery). Although the reasons of these NGF impairments are not fully comprehended, some retinal cells (glial cells, bipolar neurons, and RGCs) have been recognized partially responsible for these local changes.Taken together, the recent progress in the ocular microsurgeries might be associated with sampling of small amount of ocular humors, allowing the collection of biochemical information about diseased retina and the monitoring of treatment. The chance to detect NGF and likewise other neuroprotective or pro-/anti-inflammatory factors in these fluids would open to the possibility to identify biomarkers of early diagnosis or monitoring of retinal disease evolution/therapy (precision medicine).

Hyaluronic acid coating of gold nanoparticles for intraocular drug delivery: Evaluation of the surface properties and effect on their distribution

Due to the unique anatomical structure of the eye, ocular drug delivery is a promising delivery route for the treatment of several ocular diseases, such as the ocular neovascularization that contributes to diabetic retinopathy. This disease is triggered by inflammation, retinal ischemia, and/or deposits of advanced-glycation end-products (AGEs), as well as increased levels of vascular endothelial growth factor (VEGF), interleukins, or reactive oxygen species (ROS). Gold has unique antioxidant and antiangiogenic properties and can inhibit angiogenic molecules. Furthermore, gold nanoparticles (GNPs) are not only biocompatible, they are easy to synthesize, they absorb and scatter visible light, and they can be made with precise control over size and shape. GNPs are an excellent candidate for ocular drug delivery because they can be conjugated to an extraordinarily diverse array of different biomolecules, and surface functionalization can improve the mobility of GNPs across the physiological barriers of the eye, such as the vitreous humour or the inner limiting membrane. For this purpose, we employed low molecular weight hyaluronan (HA) to increase the mobility of the nanoparticles as well as target them to HA receptors that are expressed in different cells of the eye. In this study, the combination of gold and HA enhanced the stability of the whole carrier and promoted their distribution across ocular tissues and barriers to reach the retina. Moreover, analysis in vitro, ex vivo, and in ovo revealed the protective and antiangiogenic effect of GNPs as inhibitors of AGEs-mediated- retinal pigment epithelial cell death and neovascularization. We demonstrated that conjugation with HA enhances GNP stability and distribution due to a specific CD44 receptor interaction. The capacity of HA-GNPs to distribute through the vitreous humour and their avidity for the deeper retinal layers ex vivo, suggest that HA-GNPs are a promising delivery system for the treatment of ocular neovascularization and related disorders.

Clinical outcomes and antibiotic susceptibilities of Staphylococcus aureus endophthalmitis

PURPOSE

To compare the antibiotic susceptibilities and visual acuity (VA) outcomes in endophthalmitis caused by methicillin-resistant (MRSA) versus methicillin-sensitive S. aureus (MSSA).

METHODS

The records of 34 cases of S. aureus endophthalmitis at The New York Eye and Ear Infirmary from Jan 1997 to June 2011 were reviewed. Antibiotic susceptibility profiles over time and VA at presentation and at 3, 6, and ≥12 months were recorded. S. aureus isolates were grouped based on oxacillin resistance.

RESULTS

Of the 34 cases, 15 (44 %) were MRSA and 19 (56 %) MSSA. Median presenting VA was hand motions (logMAR 4.0) in both the MRSA and MSSA groups. There was no statistically significant difference in VA between the MRSA and MSSA groups at 3, 6, or ≥12 months. No MRSA isolates were resistant to vancomycin or gentamicin. While over 85 % of MRSA isolates tested for fourth-generation fluoroquinolones were resistant, just 10 % MSSA isolates tested were resistant. There was a trend suggesting an increase in the proportion of MRSA isolates compared to MSSA isolates over the course of the study period.

CONCLUSIONS

There was no statistical difference in short- or long-term VA outcomes between the MRSA and MSSA groups at any time point. Resistance to fourth-generation fluoroquinolones was present in over 85 % of MRSA isolates, but just 10 % of MSSA isolates. An increasing proportion of MRSA amongst S. aureus isolates was noted over the course of the study period.

Clinical applications of spectral domain optical coherence tomography in retinal diseases

Optical coherence tomography (OCT) was introduced about two decades ago and has revolutionized ophthalmic practice in recent years. It is a noninvasive noncontact imaging modality that provides a high-resolution cross-sectional image of the cornea, retina, choroid and optic nerve head, analogous to that of the histological section. Advances in OCT technology in signal detection technique from time-domain (TD) to spectral-domain (SD) detection have given us the potential to study various retinal layers more precisely and in less time. SD-OCT better delineates structural changes and fine lesions in the individual retinal layers. Thus, we have gained substantial information about the pathologic and structural changes in ocular conditions with primary or secondary retinal involvement. This review we discuss the clinical application of currently available SD-OCT in various retinal pathologies. Furthermore, highlights the benefits of SD-OCT over TD. With the introduction of enhanced depth imaging and swept – source OCT visualization of the choroid and choriocapillaris has become possible. Therefore, OCT has become an indispensable ancillary test in the diagnosis and management of diseases involving the retina and/or the choroid. As OCT technology continues to develop further it will provide new insights into the retinal and choroidal structure and the pathogenesis of posterior segment of the eye.

MicroRNA target prediction in glaucoma

Glaucoma is a progressive optic neuropathy and is one of the leading causes of blindness in the industrialized countries. The aim of this study is to investigate microRNA (miRNA) regulation in glaucoma and other neurodegenerative diseases, that share similar pathways, by means of in silico approaches such as bibliographic search and access to bioinformatic resources. First of all, data mining was carried out on Human miRNA Disease Database (HMDD) and miR2Disease databases. Then, predictions of deregulated miRNAs were carried out accessing to microrna.org database. Finally, the potential combinatorial effect of miRNAs, on regulation of biochemical pathways, was studied by an enrichment analysis performed by DIANA-miRPath v.2.0. We found, from literature search, 8 deregulated miRNAs in glaucoma and 9 and 23 in age-related macular degeneration (AMD) and Alzheimer's disease (AD), respectively. One miRNA is commonly deregulated in glaucoma and AMD (miR-23a). Two miRNAs (miR-29a, miR-29b) are common to glaucoma and AD, and four miRNAs were identified to be commonly deregulated in AMD and AD (miR-9, miR-21, miR-34a, miR-146a). The match of the miRNA common to glaucoma and the other two neurodegenerative diseases (AMD and AD) did not generate any output. Enrichment of information has been reached through miRNAs prediction: 88 predicted miRNAs are common to glaucoma and AMD, 19 are common to glaucoma and AD, and 9 are common to AMD and AD. Indeed, predicted miRNAs common to the three neurodegenerative diseases are nine (miR-107, miR-137, miR-146a, miR-181c, miR-197, miR-21, miR-22, miR-590, miR-9). DIANA-miRPath predicted that those nine miRNAs might regulate pathways involved in inflammation. The findings hereby obtained provide a valuable hint to assess deregulation of specific miRNA, as potential biomarkers and therapeutic targets, in glaucoma and other neurodegenerative diseases by means of preclinical and clinical studies.