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Topic Review
Drug Delivery Systems for Uveitis and Neuro-Ophthalmologic Conditions
To circumvent these constraints, the development of biodegradable nano-based drug delivery systems (DDS) has gained prominence. These systems promise extended residence time in ocular tissues, improved penetration through ocular barriers, and are composed of nanosized, biodegradable polymers, thereby diminishing the risk of toxicity and adverse reactions.
  • 531
  • 24 Jul 2023
Topic Review
Research Trends and Hotspots of Retinal OCT
Optical coherence tomography (OCT) is a widely used technology for high-resolution and cross-sectional imaging of tissues by measuring backscattered light. The emergence of optical coherence tomography (OCT) has sparked great interest in retinal research.
  • 530
  • 28 Sep 2022
Topic Review
AS-OCT in Corneal Disorders
Anterior segment optical coherence tomography (AS-OCT) is a non-contact method of in vivo ocular imaging technology. It uses low coherence interferometry that measures the echo time delay of light backscattered from tissue structures and combines multiple axial scans into a composite B-scan image. Earlier ultrasound bio microscopy was used for anterior segment imaging, but with time AS-OCT has become a popular imaging tool for anterior segment imaging. AS-OCT is faster and provides more in-depth assessment of the anterior chamber and is repeatable and reproducible. For AS imaging, longer wavelengths (1050–1310 nm) are preferred than retinal OCT (800–900 nm) due to higher penetration and less scattering.
  • 528
  • 15 Apr 2022
Topic Review
AMD and the Complement System
Wet age-related macular degeneration (wAMD) is characterized by choroidal neovascularization (CNV), and it is the leading cause of blindness affecting elderly in the Western world. AMD is a complex disease that has strong associations with the complement system. All three initiating complement pathways may be relevant in CNV formation, but most evidence indicates a major role for the alternative pathway (AP) and for the terminal complement complex, as well as certain complement peptides generated upon complement activation. Since the complement system is associated with AMD and CNV, a complement inhibitor may be a therapeutic option for patients with wAMD. The aim of the review is to (i) reflect on the possible complement targets in the context of wAMD pathology, (ii) investigate the results of prior clinical trials with complement inhibitors for wAMD patients, and (iii) outline important considerations when developing a future strategy for the treatment of wAMD.
  • 527
  • 22 Feb 2021
Topic Review
Basic Principles of Adaptive Optics
The eye, the photoreceptive organ used to perceive the external environment, is of great importance to humans. It has been proven that some diseases in humans are accompanied by fundus changes; therefore, the health status of people may be interpreted from retinal images. However, the human eye is not a perfect refractive system for the existence of ocular aberrations. These aberrations not only affect the ability of human visual discrimination and recognition, but restrict the observation of the fine structures of human eye and reduce the possibility of exploring the mechanisms of eye disease. Adaptive optics (AO) is a technique that corrects optical wavefront aberrations. Once integrated into ophthalmoscopes, AO enables retinal imaging at the cellular level.
  • 527
  • 19 May 2022
Topic Review
NO-cGMP Signaling in Retinal Ganglion Cell in Glaucoma
Glaucoma is a progressive age-related disease of the visual system and the leading cause of irreversible blindness worldwide. Currently, intraocular pressure (IOP) is the only modifiable risk factor for the disease, but even as IOP is lowered, the pathology of the disease often progresses. Hence, effective clinical targets for the treatment of glaucoma remain elusive. Glaucoma shares comorbidities with a multitude of vascular diseases, and evidence in humans and animal models demonstrates an association between vascular dysfunction of the retina and glaucoma pathology. Integral to the survival of retinal ganglion cells (RGCs) is functional neurovascular coupling (NVC), providing RGCs with metabolic support in response to neuronal activity. NVC is mediated by cells of the neurovascular unit (NVU), which include vascular cells, glial cells, and neurons. Nitric oxide-cyclic guanosine monophosphate (NO-cGMP) signaling is a prime mediator of NVC between endothelial cells and neurons, but emerging evidence suggests that cGMP signaling is also important in the physiology of other cells of the NVU. NO-cGMP signaling has been implicated in glaucomatous neurodegeneration in humans and mice.
  • 527
  • 21 Nov 2022
Topic Review
Uveal Melanomas
Traditionally, it has been thought that metastatic spread in uveal melanoma (UM) and dissemination occurs prior to presentation and that treatment of the primary tumor does not change outcome. However, it seems as though small UM tumours can not only be lethal with high risk monosomy 3 mutations, treated at an earlier time point at a smaller stage seems to improve mortality outcomes. 
  • 526
  • 22 Sep 2021
Topic Review
Diabetic Macular Oedema
Diabetic macular oedema (DMO) is one of the leading causes of vision loss associated with diabetic retinopathy (DR). New insights in managing this condition have changed the paradigm in its treatment, with intravitreal injections of antivascular endothelial growth factor (anti-VEGF) having become the standard therapy for DMO worldwide. However, there is no single standard therapy for all patients DMO refractory to anti-VEGF treatment; thus, further investigation is still needed.
  • 523
  • 24 Aug 2021
Topic Review
Age-Related Macular Degeneration and the Complement System
Age-related macular degeneration (AMD) is a progressive degenerative disease of the central retina and the leading cause of severe loss of central vision in people over age 50. Patients gradually lose central visual acuity, compromising their ability to read, write, drive, and recognize faces, all of which greatly impact daily life activities. Quality of life is significantly affected in these patients, and there are worse levels of depression as a result. AMD is a complex, multifactorial disease in which age and genetics, as well as environmental factors, all play a role in its development and progression. The mechanism by which these risk factors interact and converge towards AMD are not fully understood, and therefore, drug discovery is challenging, with no successful therapeutic attempt to prevent the development of this disease.
  • 523
  • 24 May 2023
Topic Review
Biologics in Uveitis Treatment
Biological drugs, especially those targeting anti-tumour necrosis factor α (TNFα) molecule, have revolutionized the treatment of patients with non-infectious uveitis (NIU), a sight-threatening condition characterized by ocular inflammation that can lead to severe vision threatening and blindness. 
  • 518
  • 15 Mar 2023
Topic Review
Emerging Pathogens and Ophthalmic Disease
Ophthalmologists are essential health care workers who provide urgent and emergent vision care services during outbreaks and address the ocular consequences of epidemic and pandemic infectious diseases. In 2017, the World Health Organization (WHO) identified high priority pathogens likely to cause a future epidemic with the goal of guiding research and development to improve diagnostic tests, vaccines, and medicines. 
  • 517
  • 14 May 2021
Topic Review
Nano-Based DDS for Anterior Segment Diseases
The eye is a delicate and complex organ protected by anatomical barriers that limit the bioavailability and residence time of topically administered drugs. Polymeric nano-based drug delivery systems (DDS) have been developed to address this challenge and improve therapeutic outcomes. Biodegradable polymers are often used in these DDS to minimize adverse effects and control the release of different loaded drugs.
  • 517
  • 12 May 2023
Topic Review
Inherited Retinal Dystrophies
Inherited retinal dystrophies (IRDs) are a group of retinal disorders that cause progressive and severe loss of vision because of retinal cell death, mainly photoreceptor cells. IRDs include retinitis pigmentosa (RP), the most common IRD. IRDs present a genetic and clinical heterogeneity that makes it difficult to achieve proper treatment. The progression of IRDs is influenced, among other factors, by the activation of the immune cells (microglia, macrophages, etc.) and the release of inflammatory molecules such as chemokines and cytokines. Upregulation of tumor necrosis factor alpha (TNFα), a pro-inflammatory cytokine, is found in IRDs. This cytokine may influence photoreceptor cell death. Different cell death mechanisms are proposed, including apoptosis, necroptosis, pyroptosis, autophagy, excessive activation of calpains, or parthanatos for photoreceptor cell death. Some of these cell death mechanisms are linked to TNFα upregulation and inflammation. Therapeutic approaches that reduce retinal inflammation have emerged as useful therapies for slowing down the progression of IRDs.
  • 514
  • 22 Sep 2021
Topic Review
Mouse Models of Retinitis Pigmentosa-59
Retinitis pigmentosa-59 (RP59) is a rare, recessive form of RP, caused by mutations in the gene encoding DHDDS (dehydrodolichyl diphosphate synthase). DHDDS forms a heterotetrameric complex with Nogo-B receptor (NgBR; gene NUS1) to form a cis-prenyltransferase (CPT) enzyme complex, which is required for the synthesis of dolichol, which in turn is required for protein N-glycosylation as well as other glycosylation reactions in eukaryotic cells. The mouse is the most commonly used vertebrate animal model in experimental biology, there have been efforts to generate murine models of RP59.
  • 514
  • 30 Nov 2022
Topic Review
Basics of Ocular Immunology
Ocular infectious diseases are an important cause of potentially preventable vision loss and blindness. Bacteria and viruses represent the more common causes of ocular infections worldwide and can affect nearly any anatomical part of the eye.
  • 514
  • 18 Aug 2023
Topic Review
Corneal Biomechanics following Laser Refractive Surgery in Eyes
The role of corneal biomechanics in laser vision correction (LVC) is being raised in the assessment of postoperative corneal ectasia risk. Research reveal the highest corneal biomechanics reduction after laser in situ keratomileusis (LASIK) followed by small incision lenticule extraction (SMILE) and surface procedures, such as photorefractive keratectomy (PRK) or laser-assisted sub-epithelial keratectomy (LASEK). In SMILE procedure treatment planning, the use of thicker caps preserves the corneal biomechanics. Similarly, reduction of flap thickness in LASIK surgery maintains the corneal biomechanical strength.
  • 511
  • 04 Jan 2023
Topic Review
Cell Therapy for Retinal and Optic Nerve Diseases
Retinal Degenerative diseases and Optic Nerve diseases have been largely characterized and are considered leading causes of blindness worldwide.  One of the hopes for possible treatments lies in cell therapy. This entry updates those that are the subject of clinical trials and therefore have a better chance of reaching clinical use. The aim of this review was to provide an update on the potential of cell therapies to restore or replace damaged and/or lost cells in retinal degenerative and optic nerve diseases, describing the available cell sources and the challenges involved in such treatments when these techniques are applied in real clinical practice.
  • 509
  • 07 Dec 2021
Topic Review
Silicone Oil in Surgical Management of Endophthalmitis
Endophthalmitis represents one of the biggest diagnostic and therapeutic challenges in modern ophthalmology. It threatens all forms of intraocular surgery from intravitreal injections to corneal transplants and vitrectomies and it is discussed on all surgical consent forms. Silicone oil reduces the risk of postoperative retinal detachment, especially in case of undetected retinal breaks, produces compartmentalization of the eye, may lead to early visual recovery, allows laser photocoagulation, prevents severe postoperative hypotony and has antimicrobic activity due to an inhibitory effect for several species of pathogens. 
  • 509
  • 24 Oct 2022
Topic Review
Olive Pomace and Ocular Surface
Oxidative- and inflammatory-related ocular surface diseases have high prevalence and are an emerging issue in ophthalmology. Olive pomace (OP) is the olive oil’s industry main by-product, and is potentially environmentally hazardous. Nevertheless, it contains phenolic compounds with important bioactivities, like oleuropein (OL) and hydroxytyrosol (HT). The antioxidant and anti-inflammatory effects of four OP extracts (CONV, OPT(1–3)), pure OL and HT, and mixtures thereof were screened on human corneal (HCE) and conjunctival epithelial (IM-ConjEpi) cells. CONV was conventionally extracted, while OPT(1–3) were produced by pressurized liquid extraction. Thanks to their improved activity, CONV and OPT3 (HT-enriched) were selected for dose-dependent studies. Cells were stimulated with tumor necrosis factor-α or ultraviolet-B radiation, measuring interleukin (IL)-1β, IL-6, IL-8, and IL-17A as well as interferon γ-induced protein [IP]-10 secretion or intracellular ROS production, respectively. On HCE, both extracts and HT inhibited the secretion of most measured ILs, demonstrating a strong anti-inflammatory effect; while in IM-ConjEpi, all samples decreased IP-10 secretion. Moreover, HT, OL, and both extracts showed strong dose-dependent antioxidant activity in both cell lines. Compared with CONV, OPT3 was active at lower concentrations, demonstrating that intensified extraction techniques are selective towards targeted biomarkers. Hence, a high-value application as potential ocular surface therapy was proposed for the OP valorization.
  • 504
  • 02 Sep 2021
Topic Review
Models of Diabetic Retinopathy
Diabetic retinopathy (DR) is an ocular complication of diabetes mellitus (DM), a metabolic disorder characterized by elevation in blood glucose level. The pathogenesis of DR includes vascular, neuronal, and inflammatory components leading to activation of complex cellular molecular signaling. If untreated, the disease can culminate in vision loss that eventually leads to blindness. Animal models mimicking different aspects of DM complications have been developed to study the development and progression of DR. Despite the significant contribution of the developed DR models to discovering the mechanisms of DR and the recent achievements in the research field, the sequence of cellular events in diabetic retinas is still under investigation. Partially, this is due to the complexity of molecular mechanisms, although the lack of availability of models that adequately mimic all the neurovascular pathobiological features observed in patients has also contributed to the delay in determining a precise molecular trigger.
  • 504
  • 16 Feb 2022
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