An Intraocular Camera for Retinal Prostheses

2007 ◽  
Author(s):  
Patrick J. Nasiatka ◽  
Michelle C. Hauer ◽  
Noelle R. B. Stiles ◽  
Jaw-Chyng Lue ◽  
Satsuki Takahashi ◽  
...  
Keyword(s):  
Photoreceptor Cells ◽  
Head Movements ◽  
Age Related Macular Degeneration ◽  
Depth Of Field ◽  
Retinal Diseases ◽  
Retinal Neurons ◽  
Retinal Prostheses ◽  
Retinal Implants ◽  
Age Related ◽  
Functional Vision

Blindness due to degenerative retinal diseases such as Retinitis Pigmentosa (RP) and Age-Related Macular Degeneration (AMD) afflict millions of people worldwide. Recent advances in retinal implants that bypass damaged photoreceptor cells and electrically stimulate the remaining healthy retinal neurons show promise for restoring functional vision to the blind [1]. Current intraocular retinal prostheses driven by an external camera mounted on the subject’s head require slow and unnatural head movements. To allow for normal foveation and expanded depth of field, a novel intraocular camera (IOC) has been designed to work in conjunction with an epiretinal microstimulator array, as shown schematically in Fig. 1.

scholarly journals Degeneration-Dependent Retinal Remodeling: Looking for the Molecular Trigger

2020 ◽  
Vol 14 ◽  
Author(s):  
Michael Telias ◽  
Scott Nawy ◽  
Richard H. Kramer
Keyword(s):  
Ganglion Cells ◽  
Photoreceptor Cells ◽  
Age Related Macular Degeneration ◽  
Retinal Ganglion ◽  
Retinal Neurons ◽  
Age Related ◽  
Retinal Remodeling ◽  
Blind Individuals ◽  
The Brain ◽  
Photoreceptor Death

Vision impairment and blindness in humans are most frequently caused by the degeneration and loss of photoreceptor cells in the outer retina, as is the case for age-related macular degeneration, retinitis pigmentosa, retinal detachment and many other diseases. While inner retinal neurons survive degeneration, they undergo fundamental pathophysiological changes, collectively known as “remodeling.” Inner retinal remodeling downstream to photoreceptor death occurs across mammalian retinas from mice to humans, independently of the cause of degeneration. It results in pervasive spontaneous hyperactivity and membrane hyperpermeability in retinal ganglion cells, which funnel all retinal signals to the brain. Remodeling reduces light detection in vision-impaired patients and precludes meaningful vision restoration in blind individuals. In this review, we summarize current hypotheses proposed to explain remodeling and their potential medical significance highlighting the important role played by retinoic acid and its receptor.

scholarly journals Pathways and disease-causing alterations in visual chromophore production for vertebrate vision

2020 ◽  
pp. jbc.REV120.014405 ◽  
Author(s):  
Philip D Kiser ◽  
Krzysztof Palczewski
Keyword(s):  
Retinal Dystrophy ◽  
Bright Light ◽  
Photoreceptor Cells ◽  
Age Related Macular Degeneration ◽  
Retinal Diseases ◽  
Visual Cycle ◽  
Light Conditions ◽  
Age Related ◽  
G Protein Coupled ◽  
Rod And Cone Photoreceptors

All that we view of the world begins with an ultrafast cis to trans photoisomerization of the retinylidene chromophore associated with the visual pigments of rod and cone photoreceptors. The continual responsiveness of these photoreceptors is then sustained by regeneration processes that convert the trans- retinoid back to an 11-cis configuration. Recent biochemical and electrophysiological analyses of the retinal G protein-coupled receptor (RGR) suggest that it could sustain the responsiveness of photoreceptor cells, particularly cones, even under bright light conditions. Thus, two mechanisms have evolved to accomplish the re-isomerization: one involving the well-studied retinoid isomerase (RPE65), and a second photoisomerase reaction mediated by the RGR. Impairments to the pathways that transform all- trans-retinal back to 11-cis-retinal are associated with mild to severe forms of retinal dystrophy. Moreover, with age there also is a decline in the rate of chromophore regeneration. Both pharmacological and genetic approaches are being used to bypass visual cycle defects and consequently mitigate blinding diseases.  Rapid progress in the use of genome editing also is paving the way for the treatment of disparate retinal diseases. In this review, we provide an update on visual cycle biochemistry and then discuss visual cycle-related diseases and emerging therapeutics for these disorders. There is hope that these advances will be helpful in treating more complex diseases of the eye, including age-related macular degeneration (AMD).

scholarly journals Development of a Fundus Image-Based Deep Learning Diagnostic Tool for Various Retinal Diseases

2021 ◽  
Vol 11 (5) ◽  
pp. 321
Author(s):  
Kyoung Min Kim ◽  
Tae-Young Heo ◽  
Aesul Kim ◽  
Joohee Kim ◽  
Kyu Jin Han ◽  
...  
Keyword(s):  
Network Models ◽  
Retinal Disease ◽  
Age Related Macular Degeneration ◽  
Diagnostic Tools ◽  
Retinal Images ◽  
Dense Layer ◽  
Retinal Diseases ◽  
Fundus Image ◽  
Neural Network Models ◽  
Age Related

Artificial intelligence (AI)-based diagnostic tools have been accepted in ophthalmology. The use of retinal images, such as fundus photographs, is a promising approach for the development of AI-based diagnostic platforms. Retinal pathologies usually occur in a broad spectrum of eye diseases, including neovascular or dry age-related macular degeneration, epiretinal membrane, rhegmatogenous retinal detachment, retinitis pigmentosa, macular hole, retinal vein occlusions, and diabetic retinopathy. Here, we report a fundus image-based AI model for differential diagnosis of retinal diseases. We classified retinal images with three convolutional neural network models: ResNet50, VGG19, and Inception v3. Furthermore, the performance of several dense (fully connected) layers was compared. The prediction accuracy for diagnosis of nine classes of eight retinal diseases and normal control was 87.42% in the ResNet50 model, which added a dense layer with 128 nodes. Furthermore, our AI tool augments ophthalmologist’s performance in the diagnosis of retinal disease. These results suggested that the fundus image-based AI tool is applicable for the medical diagnosis process of retinal diseases.

scholarly journals Visual Outcomes of Macula-Involving Rhegmatogenous Retinal Detachment in Patients with and Without Age-Related Macular Degeneration

2022 ◽  
Author(s):  
P. Barrett Paulk ◽  
Dala Eloubeidi ◽  
John O. Mason III ◽  
Christine A. Curcio ◽  
Jason N. Crosson ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Retinal Detachment ◽  
Macular Degeneration ◽  
Rhegmatogenous Retinal Detachment ◽  
Age Related Macular Degeneration ◽  
Light Perception ◽  
Postoperative Visual Acuity ◽  
Age Related ◽  
Functional Vision ◽  
Better Than

Abstract Background Patients presenting with macula-off rhegmatogenous retinal detachment (RRD) with concomitant age-related macular degeneration (AMD) and their treating physicians would benefit from knowledge regarding the visual prognosis after repair. The prognosis for such patients is not well known. The purpose of this study is to compare visual outcomes in macula-off RRD in eyes with AMD versus a group of comparison eyes without AMD. Methods This was a retrospective chart review of 1,149 patients. A total of 191 eyes met study criteria, 162 non-AMD eyes (controls) and 29 AMD eyes. The main outcome measure was postoperative visual acuity in control eyes versus AMD eyes, and this was compared using Fisher’s exact test. Results There was a statistically significant difference in postoperative visual acuity by AMD status, with those without AMD having a higher frequency of Count Fingers (CF), Hand Motion (HM), Light Perception (LP), or No Light Perception (NLP) vision (p = 0.023). More specifically 5.56% of non-AMD eyes and 3.45% of AMD eyes were 20/40 or better, 77.16% of non-AMD and 55.17% of AMD eyes were worse than 20/40 and better than 20/200, 10.49% of non-AMD eyes and 37.93% of AMD eyes were 20/200 or worse, and there were 11 eyes in the non-AMD group with CF, HM, LP, or NLP vision while there was only 1 eye in the AMD group with CF vision. Conclusions Though postoperative visual acuity was worse in the non-AMD group with a higher frequency of patients having final vision of CF, HM, LP, or NLP, this is not likely a clinically significant finding. Rather, it is a function of the difference in sample size and composition between the two groups. Importantly, this study suggests AMD patients can expect similar outcomes to non-AMD patients after RRD repair. Our study suggests that approximately 58% of patients with AMD can expect to maintain functional vision better than 20/200. We conclude that AMD patients can achieve functional vision after RRD surgery, similar to those without AMD. These findings may be helpful in guiding realistic expectations of AMD patients with RRD.

scholarly journals Review of Subthreshold Diode Micropulse Laser Treatment for Retinal Diseases

2018 ◽  
Vol 1 (1) ◽  
pp. 62-70
Author(s):  
Juhn AT ◽  
Shyu AP ◽  
Benjamin J ◽  
Zhang Y
Keyword(s):  
Diabetic Retinopathy ◽  
Treatment Modality ◽  
Branch Retinal Vein Occlusion ◽  
Age Related Macular Degeneration ◽  
Clinical Settings ◽  
Retinal Diseases ◽  
Micropulse Laser ◽  
Vein Occlusion ◽  
Age Related ◽  
New Treatment

Subthreshold Diode Micropulse (SDM) laser is a relatively new treatment modality that confers very little to no anatomical risk to the retina. However, its efficacy is still being studied, and the scenario where SDM is most useful is still being elucidated. This paper reviews articles from 1997 to 2017 and reviews the settings, results, and outcomes of SDM in various clinical settings including diabetic macular edema, branch retinal vein occlusion, central serous Chorioretinopathy, proliferative diabetic retinopathy, and age-related macular degeneration.

Retinal Prosthesis in the Treatment of Retinitis Pigmentosa

2021 ◽  
pp. 140-149
Keyword(s):  
Retinitis Pigmentosa ◽  
Retinal Prosthesis ◽  
Geographic Atrophy ◽  
Age Related Macular Degeneration ◽  
Cone Dystrophy ◽  
Research Groups ◽  
Retinal Prostheses ◽  
Retinal Degenerations ◽  
Age Related ◽  
Macular Diseases

Retinal prostheses are devices that receive an environmental visual stimulus, process it, and stimulate the degenerated retinal areas in order to produce a functionally efficient visual perception. Indications for implantation of these devices include hereditary retinal degenerations like retinitis pigmentosa, choroideremia, rod-cone dystrophy, and acquired macular diseases like geographic atrophy or fibrosis due to age-related macular degeneration. Clinically applied retinal prosthesis approaches can be classified as; epiretinal, subretinal, suprachoroidal, and scleral (transscleral suprachoroidal). In this paper, approaches of retinal prosthesis research groups, results of clinical trials, and the latest advances in their projects will be provided.

scholarly journals Antioxidant Role of PRGF on RPE Cells after Blue Light Insult as a Therapy for Neurodegenerative Diseases

2020 ◽  
Vol 21 (3) ◽  
pp. 1021 ◽  
Author(s):  
Carlota Suárez-Barrio ◽  
Susana del Olmo-Aguado ◽  
Eva García-Pérez ◽  
María de la Fuente ◽  
Francisco Muruzabal ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Human Cell Line ◽  
Antioxidant Effect ◽  
Age Related Macular Degeneration ◽  
Strong Impact ◽  
Retinal Diseases ◽  
Age Related ◽  
Gene And Protein Expression

Oxidative stress has a strong impact on the development of retinal diseases such as age-related macular degeneration (AMD). Plasma rich in growth factors (PRGF) is a novel therapeutic approach in ophthalmological pathologies. The aim of this study was to analyze the antioxidant effect of PRGF in retinal epithelial cells (EPR) in in vitro and ex vivo retinal phototoxicity models. In vitro analyses were performed on ARPE19 human cell line. Viability and mitochondrial status were assessed in order to test the primary effects of PRGF. GSH level, and protein and gene expression of the main antioxidant pathway (Keap1, Nrf2, GCL, HO-1, and NQO1) were also studied. Ex vivo analyses were performed on rat RPE, and HO-1 and Nrf2 gene and protein expression were evaluated. The results show that PRGF reduces light insult by stimulating the cell response against oxidative damage and modulates the antioxidant pathway. We conclude that PRGF’s protective effect could prove useful as a new therapy for treating neurodegenerative disorders such as AMD.

scholarly journals Activation of JNK signaling promotes all-trans-retinal–induced photoreceptor apoptosis in mice

2020 ◽  
Vol 295 (20) ◽  
pp. 6958-6971
Author(s):  
Chunyan Liao ◽  
Binxiang Cai ◽  
Yufeng Feng ◽  
Jingmeng Chen ◽  
Yiping Wu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Intraperitoneal Administration ◽  
Photoreceptor Cells ◽  
Age Related Macular Degeneration ◽  
Jnk Signaling ◽  
Age Related ◽  
Dry Amd ◽  
Induced Apoptosis ◽  
Jnk Activation ◽  
Species Production

Disrupted clearance of all-trans-retinal (atRAL), a component of the visual (retinoid) cycle in the retina, may cause photoreceptor atrophy in autosomal recessive Stargardt disease (STGD1) and dry age-related macular degeneration (AMD). However, the mechanisms underlying atRAL-induced photoreceptor loss remain elusive. Here, we report that atRAL activates c-Jun N-terminal kinase (JNK) signaling at least partially through reactive oxygen species production, which promoted mitochondria-mediated caspase- and DNA damage-dependent apoptosis in photoreceptor cells. Damage to mitochondria in atRAL-exposed photoreceptor cells resulted from JNK activation, leading to decreased expression of Bcl2 apoptosis regulator (Bcl2), increased Bcl2 antagonist/killer (Bak) levels, and cytochrome c (Cyt c) release into the cytosol. Cytosolic Cyt c specifically provoked caspase-9 and caspase-3 activation and thereby initiated apoptosis. Phosphorylation of JNK in atRAL-loaded photoreceptor cells induced the appearance of γH2AX, a sensitive marker for DNA damage, and was also associated with apoptosis onset. Suppression of JNK signaling protected photoreceptor cells against atRAL-induced apoptosis. Moreover, photoreceptor cells lacking Jnk1 and Jnk2 genes were more resistant to atRAL-associated cytotoxicity. The Abca4−/−Rdh8−/− mouse model displays defects in atRAL clearance that are characteristic of STGD1 and dry AMD. We found that JNK signaling was activated in the neural retina of light-exposed Abca4−/−Rdh8−/− mice. Of note, intraperitoneal administration of JNK–IN-8, which inhibits JNK signaling, effectively ameliorated photoreceptor degeneration and apoptosis in light-exposed Abca4−/−Rdh8−/− mice. We propose that pharmacological inhibition of JNK signaling may represent a therapeutic strategy for preventing photoreceptor loss in retinopathies arising from atRAL overload.

scholarly journals Neuroprotective Potential of Ginkgo biloba in Retinal Diseases

Planta Medica ◽  
2019 ◽  
Vol 85 (17) ◽  
pp. 1292-1303 ◽  
Author(s):  
Isabel Martínez-Solís ◽  
Nuria Acero ◽  
Francisco Bosch-Morell ◽  
Encarna Castillo ◽  
María Eugenia González-Rosende ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Ginkgo Biloba ◽  
Redox Homeostasis ◽  
Antioxidant Properties ◽  
Retinal Disease ◽  
Age Related Macular Degeneration ◽  
Retinal Diseases ◽  
Age Related ◽  
The Central Nervous System ◽  
Degenerative Processes

AbstractLike other tissues of the central nervous system, the retina is susceptible to damage by oxidative processes that result in several neurodegenerative disease such as age-related macular degeneration, diabetic retinopathy, glaucoma, ischaemic retinal disease, retinal disease produced by light oxidation, and detached retina, among other diseases. The use of antioxidant substances is a solution to some health problems caused by oxidative stress, because they regulate redox homeostasis and reduce oxidative stress. This is important for neurodegeneration linked to oxidation processes. In line with this, Ginkgo biloba is a medicinal plant with excellent antioxidant properties whose effects have been demonstrated in several degenerative processes, including retinal diseases associated with neurodegeneration. This review describes the current literature on the role of ginkgo in retinal diseases associated with neurodegeneration. The information leads to the conclusion that G. biloba extracts might be a good option to improve certain neurodegenerative retinal diseases, but more research is needed to determine the safety and efficacy of G. biloba in these retinal degenerative processes.

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