In Vivo Assessment of Retinal Phenotypes in Axenfeld-Rieger Syndrome

Purpose

Axenfeld-Rieger syndrome (ARS) is characterized by ocular anomalies including posterior embryotoxon, iridocorneal adhesions, corectopia/iris hypoplasia, and developmental glaucoma. Although anterior segment defects and glaucoma contribute to decreased visual acuity, the role of potential posterior segment abnormalities has not been explored. We used high-resolution retinal imaging to test the hypothesis that individuals with ARS have posterior segment pathology.

Methods

Three individuals with FOXC1-ARS and 10 with PITX2-ARS completed slit-lamp and fundus photography, optical coherence tomography (OCT), OCT angiography, and adaptive optics scanning light ophthalmoscopy (AOSLO). Quantitative metrics were compared to previously published values for individuals with normal vision.

Results

All individuals demonstrated typical anterior segment phenotypes. Average ganglion cell and inner plexiform layer thickness was lower in PITX2-ARS, consistent with the glaucoma history in this group. A novel phenotype of foveal hypoplasia was noted in 40% of individuals with PITX2-ARS (but none with FOXC1-ARS). Moreover, the depth and volume of the foveal pit were significantly lower in PITX2-ARS compared to normal controls, even excluding individuals with foveal hypoplasia. Analysis of known foveal hypoplasia genes failed to identify an alternative explanation. Foveal cone density was decreased in one individual with foveal hypoplasia and normal in six without foveal hypoplasia. Two individuals (one from each group) demonstrated non-foveal retinal irregularities with regions of photoreceptor anomalies on OCT and AOSLO.

Conclusions

These findings implicate PITX2 in the development of the posterior segment, particularly the fovea, in humans. The identified posterior segment phenotypes may contribute to visual acuity deficits in individuals with PITX2-ARS.

Ocular manifestations in HIV patients attending a tertiary care hospital in Eastern India and correlation of posterior segment lesions with CD4+ counts

PURPOSE

We aimed to study the ocular manifestations in human immunodeficiency virus (HIV)-infected patients and the correlation of posterior segment lesions with CD4+ counts.

METHODS

This hospital-based, cross-sectional study enrolled HIV-positive patients attending the ophthalmology department of a tertiary care hospital in Eastern India. Complete demographic information was obtained for each patient. Comprehensive ophthalmic evaluation was done in each case.

RESULTS

A total of 184 HIV-positive patients were enrolled in the study. Ocular manifestations were detected in 62 cases. The prevalence of ocular manifestations in the present study was 33.69%. Mean age of patients included in the study was 34.8 ± 10.77 years. Prevalence of ocular manifestations was highest in the age group of 30-39 years (41.93%). Highest prevalence of ocular manifestations was noted in patients with low level of education and poor socioeconomic status. Sexual transmission was the major route of HIV transmission (in 92% of cases). Posterior segment lesions were seen in 69.35% of cases. HIV retinopathy was the most common posterior segment manifestation noted in 25 eyes. Significant positive correlation was noted between severities of posterior segment findings and CD4+ counts, which we found to increase with decrease in CD4+ counts (P < 0.001).

CONCLUSION

Detailed ophthalmic evaluation including fundus examination is must in all cases of HIV/acquired immunodeficiency syndrome (AIDS) patients as it may help in early diagnosis, treatment, and prevention of sight-threatening complications due to opportunistic infections.

Trends in Formulation Approaches for Sustained Drug Delivery to the Posterior Segment of the Eye

The eye, an intricate organ comprising physical and physiological barriers, poses a significant challenge for ophthalmic physicians seeking to treat serious ocular diseases affecting the posterior segment, such as age-related macular degeneration (AMD) and diabetic retinopathy (DR). Despite extensive efforts, the delivery of therapeutic drugs to the rear part of the eye remains an unresolved issue. This comprehensive review delves into conventional and innovative formulation strategies for drug delivery to the posterior segment of the eye. By utilizing alternative nanoformulation approaches such as liposomes, nanoparticles, and microneedle patches, researchers and clinicians can overcome the limitations of conventional eye drops and achieve more effective drug delivery to the posterior segment of the eye. These innovative strategies offer improved drug penetration, prolonged residence time, and controlled release, enhancing therapeutic outcomes for ocular diseases. Moreover, this article explores recently approved delivery systems that leverage diverse polymer technologies, such as chitosan and hyaluronic acid, to regulate drug-controlled release over an extended period. By offering a comprehensive understanding of the available formulation strategies, this review aims to empower researchers and clinicians in their pursuit of developing highly effective treatments for posterior-segment ocular diseases.

Multimodal Imaging Features of the Posterior Segment in Ocular Syphilis and HIV Co-Infection: A Single Center Case Series

OBJECTIVE

To analyze the frequent multimodal imaging features in posterior syphilitic uveitis.

PURPOSE

Syphilis infection has re-emerged as a global health problem. Multimodal imaging approach has been proposed for diagnosis and follow-up; there are not previous reports dedicated to the anatomic and visual outcomes in patients diagnosed with ocular syphilis and concomitant HIV infection.

METHODS

All demographic information was recovered; a complete ophthalmological examination and multimodal imaging evaluation (retinal fluorescein angiography (FA), autofluorescence (AF), optical coherence tomography (OCT)) were performed on initial visit and 1 month after antibiotic therapy.

RESULTS

   18 eyes of 9 patients were included. The most frequent features observed were: Hyperfluorescence on optic disk on FA, Hyperautofluorescence punctate pattern on AF, Vitritis on SD-OCT. After treatment, there was a functional and anatomical improvement.

CONCLUSION

Ocular syphilis represents a diagnostic challenge. Multimodal imaging approach allows identification of structural changes, follow-up and early detection of complications.

Utility of High-Resolution Ultrasonography in the Evaluation of Posterior Segment Ocular Lesions Using Sensitivity and Specificity

Background

High-resolution Ultrasound (USG) provides good anatomical details of the ocular posterior segment and depicts the various pathological conditions affecting the ocular posterior segment, which helps ophthalmologists for choosing the best treatment options. This study aims to evaluate the utility of High-resolution Ultrasonography in the Evaluation of Posterior Segment Ocular lesions by using Sensitivity and Specificity.

Materials and Methods

A hospital-based retrospective study enrolled 81 patients in a tertiary care hospital. Clinical and ophthalmological examinations were performed followed by USG of the orbits. B-mode USG was done with a 7.5-13 MHz linear probe. The final diagnosis was made by correlating the USG findings with clinical and ophthalmological examinations.

Statistical analysis

Sensitivity, specificity, the positive predictive value, the negative predictive value, and the accuracy of B-scan USG were compared with the ophthalmological findings by using the Chi-square test.

Results

Of 81 patients (n=48 males and n=33 females) with a mean age of 38.98 ± 16.48 [SD] years, posterior segment ocular lesions in association with cataracts were found in 27 (33.3%) patients, whereas 14 (51.9%) patients had posterior vitreous detachment (PVD), 10 (37%) patients had retinal detachment (RD), and 1 (3.7%) patient had choroidal detachment (CD). Posterior segment ocular pathologies were found in 17 (21%) patients with blunt ocular injuries, whereas 8 (47.1%) patients had PVD, 4 (23.5%) patients had RD and 4 (23.5%) patients had CD. The ocular USG had a sensitivity of 87.32%, specificity of 80%, and accuracy of 86.42% with a statistically significant difference between the USG findings and the Ophthalmology diagnosis of the posterior segment ocular abnormalities of a p-value of 0.0005.

Conclusion

High-resolution ultrasound is one of the best and an easily available imaging modality for the evaluation of posterior segment ocular pathologies, especially in the presence of opaque ocular media.

Potential of TAK-593 ophthalmic emulsion for the treatment of age-related macular degeneration

Intravitreal injection therapy of anti-VEGF antibody or steroids is the mainstream for patients with age-related macular degeneration (AMD). However, since intravitreal injection is invasive administration, side effects such as endophthalmitis are major problems. In this study, we selected eye drops as a non-invasive treatment method, and aimed to develop eye drops that can deliver TAK-593 (VEGF receptor tyrosine kinase inhibitor) to the posterior segment of the eye.Since TAK-593 is a poorly water-soluble drug, the TAK-593 emulsion was formulated. The solubility of TAK-593 in various oils was measured, and the oil used for the emulsion was selected. Furthermore, viscosity enhancers were added to the emulsion in order to improve the drug delivery into the eye.As viscosity enhancer, xanthan gum was selected based on the properties and the viscosity of the emulsion. The delivery of TAK-593 to the posterior eye was increased by the formulation concentration and the addition of viscosity enhancers.In the laser-induced choroidal neovascularization model, TAK-593 emulsion eye drops showed the same angiogenesis-suppression efficacy as anti-VEGF antibody intravitreal injection. From these results, it was revealed that TAK-593 with an effective drug concentration can be delivered to the posterior eye by non-invasive eye drop administration.

Impact of preoperative posterior segment evaluation on surgical intervention in camp patients: A retrospective analysis

Purpose

To retrospectively study impact of preoperative posterior segment evaluation on surgical intervention in camp patients recruited for cataract surgery in Gujarat India.

Methods

Retrospective analysis of six months data collected from hospital electronic medical record (EMR) system of 9820 admitted patients recruited from screening camp for cataract surgery from 1/10/2019 to 31/3/2020 in Tertiary Eye Hospital in Gujarat, India, has been done. Comprehensive clinical evaluation, of both anterior and posterior segment which included detailed history; best corrected visual acuity (BCVA); intraocular pressure measurement with non-contact tonometer (NCT) and when required with Goldman applanation tonometer; slit lamp examination; and fundus examination with + 90 diopter lens as well as indirect ophthalmoscope as and when indicated. In case there was no view of retina, a B-scan ultrasound was done to rule out any posterior segment pathology. Immediate surgical intervention done was assessed and results analyzed in percentage.

Results

Cataract surgery was advised for 8390 patients (85.43%). Surgical intervention for management of glaucoma was done for 68 patients (0.692%). Retina intervention was done for 86 patients. Posterior segment evaluation changed immediate surgical plane of management for 154 (1.57%) patients.

Conclusion

Comprehensive clinical evaluation is economical and should be mandatory especially in community services as comorbid conditions like glaucoma, diabetic retinopathy, retinal vein occlusion, and other varied posterior segment diseases contribute significantly to visual disability in elderly age group. It is difficult to follow these patients later if manageable comorbidity is not informed about and if indicated dealt simultaneously for visual rehabilitation of patient.

Every nano-step counts: a critical reflection on do's and don'ts in researching nanomedicines for retinal gene therapy

INTRODUCTION

Retinal disease affects millions of people worldwide, generating a massive social and economic burden. Current clinical trials for retinal diseases are dominated by gene augmentation therapies delivered with recombinant viruses as key players. As an alternative, nanoparticles hold great promise for the delivery of nucleic acid therapeutics as well. Nevertheless, despite numerous attempts, 'nano' is in practice not as successful as aspired and major breakthroughs in retinal gene therapy applying nanomaterials are yet to be seen.

AREAS COVERED

In this review, we summarize the advantages of nanomaterials and give an overview of nanoparticles designed for retinal nucleic acid delivery up to now. We furthermore critically reflect on the predominant issues that currently limit nano to progress to the clinic, where faulty study design and the absence of representative models play key roles.

EXPERT OPINION

Since the current approach of in vitro - in vivo experimentation is highly inefficient and creates misinformation, we advocate for a more prominent role for ex vivo testing early on in nanoparticle research. In addition, we elaborate on several concepts, including systematic studies and open science, which could aid in pushing the field of nanomedicine beyond the preclinical stage.

Nanostructured Lipid Carriers for Enhanced Transscleral Delivery of Dexamethasone Acetate: Development, Ex Vivo Characterization and Multiphoton Microscopy Studies

Corticosteroids, although highly effective for the treatment of both anterior and posterior ocular segment inflammation, still nowadays struggle for effective drug delivery due to their poor solubilization capabilities in water. This research work aims to develop nanostructured lipid carriers (NLC) intended for periocular administration of dexamethasone acetate to the posterior segment of the eye. Pre-formulation studies were initially performed to find solid and liquid lipid mixtures for dexamethasone acetate solubilization. Pseudoternary diagrams at 65 °C were constructed to select the best surfactant based on the macroscopic transparency and microscopic isotropy of the systems. The resulting NLC, obtained following an organic solvent-free methodology, was composed of triacetin, Imwitor® 491 (glycerol monostearate >90%) and tyloxapol with Z-average = 106.9 ± 1.2 nm, PDI = 0.104 ± 0.019 and zeta potential = -6.51 ± 0.575 mV. Ex vivo porcine sclera and choroid permeation studies revealed a considerable metabolism in the sclera of dexamethasone acetate into free dexamethasone, which demonstrated higher permeation capabilities across both tissues. In addition, the NLC behavior once applied onto the sclera was further studied by means of multiphoton microscopy by loading the NLC with the fluorescent probe Nile red.

Research Progress of Bioinspired Nanostructured Systems for the Treatment of Ocular Disorders

How to enhance the bioavailability and prolong the residence time of drugs in the eye present the major barriers to traditional eye delivery. Nanotechnology has been widely used in ocular drug delivery systems because of its advantages of minimizing adverse reactions, decreasing the frequency of administration, prolonging the release time, and improving the bioavailability of the drug in the eye. As natural product-based nanostructured systems, bioinspired nanostructured systems have presented as less toxic, easy to prepare, and cost-effective and have potential application value in the field of nanotechnology. A systematic classification of bioinspired nanostructured systems based on their inspiration source and formulation and their brief applications in disease are presented here. A review of recent research progress of the bioinspired nanostructured systems for the treatment of the anterior and posterior segment of ocular disorders is then presented in detail. Finally, current challenges and future directions with regard to manufacturing bioinspired nanomaterials are provided.

Multimodal imaging of soccer ball-related ocular posterior segment injuries

PURPOSE

To investigate the clinical and anatomic characteristics of soccer ball-induced posterior segment injuries in the era of modern multi-modal imaging.

METHODS

Retrospective case series of patients with soccer ball injury and diagnostic imaging from 2007 to 2020 at a single vitreoretinal practice.

RESULTS

Eight patients met inclusion criteria. Fundus photographs (FP) and optical coherence tomography (OCT) were obtained in eight patients, fundus autofluorescence (FAF) in five patients, fluorescein angiography (FA) in three patients, and en-face OCT and OCT-Angiography (OCT-A) were obtained in two patients each. FA and FAF identified traumatic pigment epitheliopathy secondary to commotio. Increased hypo-autofluorescence was associated with shallow, peripheral retinal detachment on FAF. OCT of the macula displayed outer retinal changes associated with commotio, and offered insight into the acute and subacute changes of traumatic macular hole formation. A patient displayed foveal hyper-reflectivity in the shape of an hourglass with retinal cyst at the level of the external limiting membrane (ELM) as seen on OCT and En-face OCT. A patient with commotio involving the macula lacked microvascular changes on OCT-A.

CONCLUSION

OCT, FA, and FAF imaging may aid in the work-up and management of the soccer ball-related posterior segment injuries.

Alzheimer's Disease Seen through the Eye: Ocular Alterations and Neurodegeneration

Alzheimer’s Disease (AD) is one of the main neurodegenerative diseases worldwide. Unfortunately, AD shares many similarities with other dementias at early stages, which impedes an accurate premortem diagnosis. Therefore, it is urgent to find biomarkers to allow for early diagnosis of the disease. There is increasing scientific evidence highlighting the similarities between the eye and other structures of the CNS, suggesting that knowledge acquired in eye research could be useful for research and diagnosis of AD. For example, the retina and optic nerve are considered part of the central nervous system, and their damage can result in retrograde and anterograde axon degeneration, as well as abnormal protein aggregation. In the anterior eye segment, the aqueous humor and tear film may be comparable to the cerebrospinal fluid. Both fluids are enriched with molecules that can be potential neurodegenerative biomarkers. Indeed, the pathophysiology of AD, characterized by cerebral deposits of amyloid-beta (Aβ) and tau protein, is also present in the eyes of AD patients, besides numerous structural and functional changes observed in the structure of the eyes. Therefore, all this evidence suggests that ocular changes have the potential to be used as either predictive values for AD assessment or as diagnostic tools.

Lipid Nanoparticles for the Posterior Eye Segment

This review highlights the application of lipid nanoparticles (Solid Lipid Nanoparticles, Nanostructured Lipid Carriers, or Lipid Drug Conjugates) as effective drug carriers for pathologies affecting the posterior ocular segment. Eye anatomy and the most relevant diseases affecting the posterior segment will be summarized. Moreover, preparation methods and different types and subtypes of lipid nanoparticles will also be reviewed. Lipid nanoparticles used as carriers to deliver drugs to the posterior eye segment as well as their administration routes, pharmaceutical forms and ocular distribution will be discussed emphasizing the different targeting strategies most recently employed for ocular drug delivery.

Posterior segment manifestations and imaging features post-COVID-19

Background

To report the posterior segment (uvea and retinal) manifestations and imaging characteristics of eyes of patients with and after coronavirus disease 2019 (COVID-19).

Methods

We searched the PubMed/MEDLINE database to identify relevant articles using the following search terms: COVID-19, SARS-CoV-2, retina, uvea, optic nerve, retinal findings, posterior segment manifestations, and endophthalmitis. Articles published from December 1, 2019, to May 30, 2021, and indexed in PubMed/ MEDLINE were screened.

Results

For the purpose of this review, we included clinical features of 26 case reports and 8 case series. The posterior segment manifestations reported included cotton wool spots, retinal hemorrhages, central serous retinopathy, papillophlebitis, optic neuritis, panuveitis, multifocal retinitis, necrotizing retinitis, central retinal artery/vein occlusion, and Purtschner like retinopathy. In this review, we have also included optical coherence tomography angiography (OCTA) features that have been described in COVID-19 patients with pneumonia.

Conclusions

COVID-19 patients can experience uveo-retinal manifestations even after recovery. These patients, even if asymptomatic for eye symptoms, should undergo an eye evaluation to rule out posterior segment involvement. OCTA performed in these patients revealed microvascular changes in the superficial and deep retinal plexuses. Some of these patients may require anticoagulant or antiplatelet therapy.

First Case of Subretinal Ocular Angiostrongyliasis Associated with Retinal Detachment in the United States

Angiostrongylus cantonensis, commonly known as the rat lungworm, is mostly found in Asia, the Pacific Basin, and the Caribbean, but is also endemic in Hawai'i, especially on the Island of Hawai'i. Ocular angiostrongyliasis is an uncommon but previously reported complication associated with permanent vision loss. This is the first reported case of ocular angiostrongyliasis involving the retina or posterior segment of the eye in the US. A 24-year-old male from Chicago visited the Island of Hawai'i, where he worked on a farm and ate a vegetarian diet. When he returned to Chicago, he became sick and was hospitalized for eosinophilic meningitis. One month later, he developed a retinal detachment which required surgical repair involving a pars plana vitrectomy. During the reattachment of the retina during surgery, a live motile was identified nematode in the subretinal space. An endolaser probe immobilized and killed the nematode, and it was subsequently extracted through the sclerotomy. Thermal scars around all retinal holes including the retinotomy site were made to stabilize the retina, and perfluoropropane gas was injected to achieve temporary tamponade. Thereafter, the patient's cerebrospinal fluid returned positive for angiostrongylus cantonensis antibodies. During extended follow-up, the patient eventually lost all vision in the affected eye due to recurrent retinal detachment. This case of ocular angiostrongyliasis demonstrates the importance of obtaining travel history from endemic areas, knowing the risk of developing eosinophilic meningitis, and understanding the risk of permanent vision loss in cases involving the retina.

Vitreoretinal abnormalities in corona virus disease 2019 patients: What we know so far

The coronavirus disease 2019 (COVID-19) has become a global pandemic since December 2019. Although COVID-19 primarily affects the respiratory systems, it has become abundantly clear that it involves multiple organs including the heart, kidney, skin, and brain. Neuro-ophthalmic signs and anterior segment inflammation of the eyes were documented in COVID-19 patients recently. Small but growing number of literatures has also reported the cases of new onset vitreoretinal disorders related to COVID-19 infection. A comprehensive search from four online databases was done. Findings show vitreoretinal involvement in COVID-19 patients including the central retinal vein occlusion, central retinal artery occlusion, reactivation of previous uveitis, chorioretinitis, macular hemorrhage, acute macular neuroretinopathy, paracentral acute middle maculopathy, vitritis with outer retinal abnormalities, varicella zoster virus-related acute retinal necrosis in immunocompromised patient, and other posterior segment pathological changes. The hypotheses for potential pathogenesis of these manifestations are direct viral ocular infection and thromboembolic complications secondary to the hyperinflammatory response. This is the first review article, which provides an overview of current evidence regarding the vitreoretinal manifestations in COVID-19 patients.

Double-Needle Yamane Technique Using Flanged Haptics in Ocular Trauma-A Retrospective Survey of Visual Outcomes and Safety

To evaluate visual outcomes and safety of the double-needle technique using flanged haptics (Yamane technique) in patients with aphakia caused by ocular trauma at a trauma referral center. Retrospective: Consecutive interventional case series of 30 patients who underwent the Yamane technique due to posttraumatic aphakia. The double-needle technique using flanged haptics was combined with anterior vitrectomy (group A) in 14 patients, and with pars plana vitrectomy (PPV) (group B) due to retinal detachment, nucleus dislocation into the vitreous cavity, or intraocular lens (IOL) displacement in 16 patients. No intraoperative complications were noted. There was significant improvement in the visual acuity in both groups at the second postoperative visit. However, the visual acuity was significantly worse in the group treated with the Yamane technique combined with PPV. Silicone oil tamponade in PPV group was associated with worse visual acuity, whereas post lensectomy status was associated with poor visual function result in the anterior vitrectomy group. There was one case of slight IOL decentration and one retinal detachment during the postoperative follow-up period in the group with PPV. In this case series, the Yamane technique applied in traumatized eyes was found to be an efficacious and safe procedure. Combining the Yamane technique with PPV due to posterior segment ocular trauma was associated with worse functional results in the follow-up at three months. Further studies with longer follow-up evaluations are required to verify long-term complications.

Evaluating the Safety, Efficacy and Patient Acceptability of Intravitreal Fluocinolone Acetonide (0.2mcg/Day) Implant in the Treatment of Non-Infectious Uveitis Affecting the Posterior Segment

Long-acting, slow-release injectable fluocinolone intravitreal implants have been approved for the treatment of non-infectious uveitis affecting the posterior segment. We summarise the development of intravitreal fluocinolone implants and discuss the technology including pharmacokinetics. We conducted a systematic review of evidence for the efficacy, safety and patient acceptability of fluocinolone 0.18 mg and 0.19 mg injectable implants. We summarise evidence from the pivotal phase 3 studies that lead to the approval of these implants and evaluate real-world including disease-specific evidence. Safety including injection-related events and long-term adverse events is presented.

Penetration Enhancers for Topical Drug Delivery to the Ocular Posterior Segment-A Systematic Review

There is an unmet clinical need for eye drop formulations to efficiently treat the diseases of the posterior ocular segment by non-invasive topical administration. Here, we systematically reviewed the literature on ocular penetration enhancers and their ability to transfer drugs to the posterior segment of the eye in experimental studies. Our aim was to assess which penetration enhancer is the most efficient at delivering drugs to the posterior segment of the eye, when topically applied. We conducted a comprehensive search in three electronic databases (Ovid Embase, Ovid MEDLINE, and PubMed) to identify all the relevant manuscripts reported on ocular penetration enhancers based on the PRISMA guidelines. We identified 6540 records from our primary database search and filtered them per our inclusion/exclusion criteria to select a final list of 14 articles for qualitative synthesis. Of these, 11 studies used cell penetrating peptides (CPPs), 2 used chitosan, and 1 used benzalkonium chloride (BAC) as the penetration enhancer. Cationic and amphipathic CPPs, transactivator of transcription (TAT), and penetratin can be inferred to be the best among all the identified penetration enhancers for drug delivery to the fundus oculi via topical eye drop instillation. Further high-quality experimental studies are required to ascertain their quantitative efficacy.

Posterior segment conditions associated with myopia and high myopia

Myopia, and especially high myopia, is associated with a number of posterior segment changes that are considered to be mostly a consequence of the increased axial elongation. This can result in mechanical strain, attendant vascular changes, stretching and thinning of tissues, and atrophy/deformation of tissues in later or more advanced stages. Such myopia-related changes are observed as changes and/or abnormalities in the vitreous, choroid, retina and peripheral retina, sclera and/or optic disc. Although many of these changes are benign, at times they may be associated with significant vision impairment that either requires active intervention or may suggest future progression of the disease. This review systematically addresses the posterior segment conditions seen in myopic eyes, describes the features associated with the condition and details management pathways.

Cutis marmorata telangiectatica congenita: a focus on its diagnosis, ophthalmic anomalies, and possible etiologic factors

Purpose: Cutis marmorata telangiectatica congenita (CMTC) is a rare congenital disorder typified by localized or generalized cutaneous vascular anomalies, which dissipate over time. We review the diagnostic approach to CMTC and present a comprehensive examination of its ocular manifestations. Additionally, we offer recommendations for the ophthalmologic workup for patients with CMTC. Finally, we examine the possible causes of CMTC and summarize the current efforts to establish an etiologic mechanism for this disease.Methods: Thirty-three published cases of CMTC with ocular anomalies are examined in detail.Results: CMTC is diagnosed based on a specific set of congenital cutaneous symptoms, principally congenital reticular erythema that is unresponsive to local warming and absence of venectasia within the skin lesions. Ocular findings are not currently employed in this diagnostic process, likely due to an incomplete understanding into their presentation, frequency, and natural history. We show that the majority of ophthalmic manifestations are congenital, with glaucoma and posterior segment anomalies, consisting of retinal perfusion defects and vascular abnormalities, as the most frequently reported findings. Typical ophthalmic medical and surgical interventions appear to be effective for management of these CMTC-related pathology. Unfortunately, the etiology and pathophysiology of CMTC remains unknown, which obfuscates efforts to identify, examine, and initiate treatment in patients.Conclusions: While the ophthalmic community has traditionally viewed glaucoma as the classic ocular anomaly of CMTC, this dataset advocates for the prompt investigation of posterior segment abnormalities as well. However, our understanding of CMTC's ocular anomalies is complicated by a lack of reporting and/or incomplete (or nonexistent) ophthalmic examinations, and we strongly encourage comprehensive ophthalmic examinations for all CMTC patients at the time of diagnosis, followed by appropriate screening and surveillance throughout life. We believe these recommendations will spur additional data and disease insights that may be useful for future refinements to CMTC diagnostic algorithms.

Size-Exclusive Nanoporous Biodegradable PLGA Capsules for Drug Delivery Implants and In Vivo Stability in the Posterior Segment

The current standard of care for posterior segment eye diseases, such as neovascular age-related macular degeneration, diabetic macular edema, is frequent intravitreal injections or sustained-release drug implants. Intravitreal injections have a low incidence of serious complications such as retinal detachment, endophthalmitis, iatrogenic traumatic cataract, or iridocyclitis and injection-site reactions. However, there is a significant burden to the patient, the patient's family, and the health system because current intravitreal therapies require between every 4 and 12 week administration over many years. Drug implants have side effects due to the burst release of the drugs, and their release cannot be easily controlled after implantation. We have developed a size-exclusive nanoporous biodegradable PLGA capsule for dosage-controllable drug delivery implants. We have optimized the nanoporous structure by tuning the ratio between porogen and high molecular weight PLGA and tested the stability against passive leakage of the liposomal drug (1-2 μm) and the safety in vivo rabbit eyes for 6 months. Our results suggest that PLGA implants made of the nanoporous PLGA sheet can selectively release drug molecules, keeping the liposomal drug inside. In addition, the implant was biocompatible, causing no inflammation and foreign body response when implanted for 6 months. Overall, the implant shows great potential for on-demand dose-controllable drug release applications.

A more efficient ocular delivery system of triamcinolone acetonide as eye drop to the posterior segment of the eye

As a leading cause of vision impairment of the retina, macular edema (ME) has one of the highest clinical demands for treatment. Current treatment of ME relies heavily on invasive techniques resulting in complications and poor patient compliance. To enhance the efficiency of triamcinolone acetonide as eye drop to the posterior segment of the eye, we developed and characterized a novel formulation, namely, triamcinolone acetonide chitosan-coated liposomes (TA-CHL), prepared by the calcium acetate gradient method with some modifications. TA-CHL provided the mean particle size of 135.46 ± 4.49 nm and high entrapment efficiency (90.66 ± 3.21%), exhibited a sustained release profile, excellent physical stability, and no significant toxicity on cornea, conjunctiva, and retina. Optical coherence tomography system (OCT) was used to detect pharmacokinetics of CHL in vivo, indicating that CHL had good potency for drug delivery. Cellular uptake experiments showed CHL had the higher transduction efficiency into HCEC and ARPE-19 than liposomes. TA-CHL was shown to be potentially effective eye drop to contribute to the posterior segment of the eye.

Topical Drug Delivery to the Posterior Segment of the Eye: Addressing the Challenge of Preclinical to Clinical Translation

Topical delivery of therapeutics to the posterior segment of the eye remains the “holy grail” of ocular drug delivery. As an example, anti–vascular endothelial growth factor biologics, such as ranibizumab, aflibercept, and bevacizumab, are delivered by intravitreal injection to treat neovascular age-related macular degeneration and, although these drugs have revolutionized treatment of the disease, less invasive alternatives to intravitreal injection are desired. Multiple reports in the literature have demonstrated topical delivery of both small and large molecules to the back of the eye in small animal models. Despite this progress, successful translation to larger species, and ultimately humans, has yet to be demonstrated. Selection of animal models with relevant ocular anatomy and physiology, along with appropriate experimental design, is critical to enable more relevant feasibility assessments and increased probability of successful translation.

Qualitative and quantitative assessment of posterior segment optical coherence tomography images using standard photos: the Liwan Eye Study

BACKGROUND/AIMS

To develop a standardised grading scheme, using standard photos, for spectral-domain ocular coherence tomography (SD-OCT) images of the posterior eye and evaluate the interobserver agreement among trained ophthalmologists in identifying pathological changes.

METHODS

Subjects were recruited from Liwan District, Guangzhou, with SD-OCT data collection from June 2013 to November 2013 as part of 10-year follow-up visits from the Liwan Eye Study. All subjects underwent SD-OCT imaging of the macula with scanning lines analysed by two ophthalmologists to assess for the presence of 12 different posterior segment lesions. Per cent agreement for each lesion between the graders and quantitative measures of dome-shaped macula (DSM) height and choroidal thickness were calculated.

RESULTS

A total of 679 SD-OCT images from 679 subjects were independently evaluated by the two graders. Each of the 12 lesions was successfully graded as present or absent in over 96% of images. For all lesions, per cent agreement between observers was over 90%, ranging from 90.7% for epiretinal membranes and retinal pigment epithelium thickenings to 99.7% for full thickness macular holes and retinal detachments. Quantitative measurements of DSM height and choroidal thickness at three locations of the eye all exhibited intraclass correlation scores between the two graders of greater than 0.9.

CONCLUSION

Our study demonstrates high concordance between graders in characterising posterior segment lesions using SD-OCT images, validating the continued use of this imaging modality in the diagnosis of posterior eye disease.

Controllable continuous sub-tenon drug delivery of dexamethasone disodium phosphate to ocular posterior segment in rabbit

Corticosteroids have been used for treatment of posterior segment eye diseases, but the delivery of drug to the posterior segments is still a problem to resolve. In our study, we explore the feasibility of Sub-tenon’s Controllable Continuous Drug Delivery to ocular posterior segment. Controllable continuous sub-tenon drug delivery (CCSDD) system, intravenous injections (IV) and sub-conjunctival injections (SC) were used to deliver dexamethasone disodium phosphate (DEXP) in rabbits, the dexamethasone concentration was measured in the ocular posterior segment tissue by Shimadzu LC-MS 2010 system at different time points in 24 h after first dose injection. Levels of dexamethasone were significantly higher at 12, 24 h in CCSDD than two other approaches, and at 3, 6 h in CCSDD than IV in vitreous body (p < 0.01); at 6, 12, 24 h in CCSDD than two other approaches, and at 1, 3 h in CCSDD than IV in retinal/choroidal compound (p < 0.01); at 3, 6, 12, 24 h in CCSDD than two other approaches, and at 1 h in CCSDD than IV in sclera (p < 0.05). The AUC_0–24 in CCSDD group is higher than two other groups in all ocular posterior segment tissue. Our results demonstrated that dexamethasone concentration could be sustained moderately higher in the posterior segment by CCSDD than SC and IV, indicating that CCSDD might be a therapeutic alternative to treat a variety of intractable posterior segment diseases.

A minimally invasive adjustable-depth blunt injector for delivery of pharmaceuticals into the posterior pole

PURPOSE

To investigate the feasibility and safety of a novel minimally invasive adjustable-depth blunt injector for pharmaceuticals delivery into the posterior segment.

METHODS

Indocyanine green (ICG), sodium fluorescein and iron oxide nanoparticles (IONPs) were injected using the new injector into the extravascular spaces of the choroid (EVSC) compartment of rabbits and cadaver pig eyes. Spectral domain optical coherence tomography (SD-OCT), fundus imaging and histology analysis were performed for assessment of injection safety and efficacy.

RESULTS

Indocyanine green, fluorescein and IONPs were detected across the EVSC in rabbit eyes, covering over 80 per cent of the posterior eye surface. Injected IONPs were retained in the EVSC for at least 2 weeks following injection. No retinal detachment, choroidal haemorrhage or inflammation was detected in any of the injected eyes. In cadaver pig eyes, ICG was detected across the EVSC.

CONCLUSIONS

This novel minimally invasive delivery system may be used to safely deliver large volumes of pharmaceuticals into a new treatment reservoir compartment - the EVSC which can serve as a depot, in close proximity to the retina, covering most of the surface of the back of the eye without insertion of surgical instruments under the central retina. This system is predicted to enhance the therapeutic effect of treatments for posterior eye disorders.

Right posterior segment graft in living donor liver transplantation

AIM

Living donor liver transplantation (LDLT) is widely performed for end-stage liver disease. Liver volume is important for donor safety and recipient survival. In adult-to-adult LDLT, left lobe graft is frequently insufficient for the recipient, while right lobe graft carries a higher donor risk. The right posterior segment graft (RPSG) was introduced to increase donor selection options. However, only a few institutions have reported LDLT with an RPSG.

METHODS

In total, 587 adult recipients underwent LDLT at Kyoto University Hospital from 2001 to 2011. Here, we retrospectively report 14 LDLT with RPSG. All donors underwent volumetric analyses and detailed investigation of the hepatic vein (HV), portal vein (PV), hepatic artery (HA) and biliary duct (BD). Anatomical anomalies were detected in four donors' BD. The mean Model for End-Stage Liver Disease score was 22.6 ± 12.4 points. ABO blood groups were characterized as incompatible in three cases. The mean graft-to-recipient weight ratio was 0.897 ± 0.203.

RESULTS

Donors' postoperative courses were uneventful. To adjust diameters and lengths between grafts and recipients, dual anastomoses for PV reconstruction and graft interpositions for PV and HA reconstruction were required in one case each. HA thrombosis occurred in two cases and PV thrombosis in one. Biliary complications occurred in two cases. Though there was no significant difference in survival following RPSG versus other grafts, critical complications were observed in recipients.

CONCLUSION

The RPSG is a useful option in LDLT. However, careful consideration is required for RPSG harvest and LDLT performance, both before and during surgery.

Novel Nanomicellar Formulation Approaches for Anterior and Posterior Segment Ocular Drug Delivery

One of the most challenging areas of pharmaceutical research is ocular drug delivery. The unique anatomy and physiology of the eye impedes drug permeation to deeper ocular tissues. Nanosized carrier systems such as nanoparticles, liposomes, suspensions, dendrimers, and nanomicelles are being explored for ocular drug delivery. In this review, we have focused on application of emerging nanomicellar carrier systems in ocular drug delivery. Nanomicelles are nanosized vesicular carriers formed from amphiphilic monomer units. Surfactant and polymeric micellar nanocarriers provide an amenable means to improve drug solubilization, develop clear aqueous formulations and deliver drugs to anterior and posterior ocular tissues. Nanomicelles due to their amphiphilic nature encapsulate hydrophobic drugs and aid in drug delivery. Various methods are employed to develop nanosized micellar formulations depending upon the physicochemical properties of the drug. Nanomicellar carriers appear to be promising vehicles with potential applications in ocular drug delivery. In this review, we attempted to discuss about the progress in ocular drug delivery research using nanomicelles as carriers from the published literature and issued patents. Also, with regards to ocular static and dynamic barriers which prevent drug permeation, a brief discussion about nanomicelles, types of nanomicelles, their methods of preparation and micellar strategy to overcome ocular barriers, delivering therapeutic levels of drugs to anterior and posterior ocular tissues are discussed.