Local delivery of corticosteroids in clinical ophthalmology: A review

Corneal fibrosis: From in vitro models to current and upcoming drug and gene medicines

Fibrotic diseases are characterised by myofibroblast differentiation, uncontrolled pathological extracellular matrix accumulation, tissue contraction, scar formation and, ultimately tissue / organ dysfunction. The cornea, the transparent tissue located on the anterior chamber of the eye, is extremely susceptible to fibrotic diseases, which cause loss of corneal transparency and are often associated with blindness. Although topical corticosteroids and antimetabolites are extensively used in the management of corneal fibrosis, they are associated with glaucoma, cataract formation, corneoscleral melting and infection, imposing the need of far more effective therapies. Herein, we summarise and discuss shortfalls and recent advances in in vitro models (e.g. transforming growth factor-β (TGF-β) / ascorbic acid / interleukin (IL) induced) and drug (e.g. TGF-β inhibitors, epigenetic modulators) and gene (e.g. gene editing, gene silencing) therapeutic strategies in the corneal fibrosis context. Emerging therapeutical agents (e.g. neutralising antibodies, ligand traps, receptor kinase inhibitors, antisense oligonucleotides) that have shown promise in clinical setting but have not yet assessed in corneal fibrosis context are also discussed.

Clinical efficacy of dexamethasone parabulbar injection in patients with Nonarteritic anterior ischemic optic neuropathy

Background

Nonarteritic anterior ischemic optic neuropathy (NAAION) is a common optic neuropathy that often leads to significant visual acuity loss in patients. The present study evaluated the effects of parabulbar dexamethasone injection on visual outcomes in patients with NAAION.

Methods

This retrospective case-control study included patients diagnosed with NAAION between January 2019 and December 2022. Thirty-four patients with NAAION (34 eyes) received dexamethasone parabulbar injections, while 39 patients with NAAION (39 eyes) received oral corticosteroid treatment (control group). Best-corrected visual acuity (BCVA), visual field (VF) defect, and retinal nerve fiber layer (RNFL) thickness of the affected eye were compared between groups at baseline and 2, 6, and 12 weeks post-treatment.

Results

Mean BCVA significantly improved after 6 and 12 weeks in the injection groups compared with the control group (all P < 0.01). The visual field indices, mean deviation and pattern standard deviation significantly improved in the injection group compared with the control group after 2, 6, and 12 weeks (all P < 0.01). The RNFL showed a remarkable decrease in edema after 6 weeks (superior and nasal P values 0.005 and 0.013, respectively) in the injection group compared with the control group. Significant RNFL thinning was also observed in superior, inferior, temporal, and nasal quadrants in the control group after 12 weeks (all P values < 0.01). Also, fewer side effects were observed in the injection group compared to the control group.

Conclusions

The results of this study suggested that dexamethasone parabulbar injection might be a safe and effective intervention for relieving visual acuity and VF in patients with NAAION.

Allergic Reaction to Tropicamide Eye Drops: A Case Report

This case report presents the clinical scenario of a 50-year-old man who developed swelling and itching around both eyes after applying tropicamide eye drops for an ophthalmic examination. The swelling appeared suddenly, progressed over time, and was accompanied by redness, watery discharge, and conjunctival congestion. A dermoscopic examination revealed congestion and erythema in the affected area. Visual acuity was compromised in the left eye. Prompt identification of the eyedrops as plain tropicamide with chlorbutol as a preservative enabled timely treatment with intravenous hydrocortisone and topical steroids, resulting in symptom improvement within two days. Allergic reactions to mydriatic agents such as tropicamide are infrequent but should be considered in patients with acute ocular symptoms post-application. This case underscores the importance of recognising and managing allergic reactions to ophthalmic medications for optimal patient care.

Minocycline-loaded nHAP/PLGA microspheres for prevention of injury-related corneal angiogenesis

BACKGROUND

Corneal neovascularization (CoNV) threatens vision by disrupting corneal avascularity, however, current treatments, including pharmacotherapy and surgery, are hindered by limitations in efficacy and adverse effects. Minocycline, known for its anti-inflammatory properties, could suppress CoNV but faces challenges in effective delivery due to the cornea's unique structure. Therefore, in this study a novel drug delivery system using minocycline-loaded nano-hydroxyapatite/poly (lactic-co-glycolic acid) (nHAP/PLGA) nanoparticles was developed to improve treatment outcomes for CoNV.

RESULTS

Ultra-small nHAP was synthesized using high gravity technology, then encapsulated in PLGA by a double emulsion method to form nHAP/PLGA microspheres, attenuating the acidic by-products of PLGA degradation. The MINO@PLGA nanocomplex, featuring sustained release and permeation properties, demonstrated an efficient delivery system for minocycline that significantly inhibited the CoNV area in an alkali-burn model without exhibiting apparent cytotoxicity. On day 14, the in vivo microscope examination and ex vivo CD31 staining corroborated the inhibition of neovascularization, with the significantly smaller CoNV area (29.40% ± 6.55%) in the MINO@PLGA Tid group (three times daily) than that of the control group (86.81% ± 15.71%), the MINO group (72.42% ± 30.15%), and the PLGA group (86.87% ± 14.94%) (p < 0.05). Fluorescein sodium staining show MINO@PLGA treatments, administered once daily (Qd) and three times daily (Tid) demonstrated rapid corneal epithelial healing while the Alkali injury group and the DEX group showed longer healing times (p < 0.05). Additionally, compared to the control group, treatments with dexamethasone, MINO, and MINO@PLGA were associated with an increased expression of TGF-β as evidenced by immunofluorescence, while the levels of pro-inflammatory cytokines IL-1β and TNF-α demonstrated a significant decrease following alkali burn. Safety evaluations, including assessments of renal and hepatic biomarkers, along with H&E staining of major organs, revealed no significant cytotoxicity of the MINO@PLGA nanocomplex in vivo.

CONCLUSIONS

The novel MINO@PLGA nanocomplex, comprising minocycline-loaded nHAP/PLGA microspheres, has shown a substantial capacity for preventing CoNV. This study confirms the complex's ability to downregulate inflammatory pathways, significantly reducing CoNV with minimal cytotoxicity and high biosafety in vivo. Given these findings, MINO@PLGA stands as a highly promising candidate for ocular conditions characterized by CoNV.

Thiophene-based lipids for mRNA delivery to pulmonary and retinal tissues

Lipid nanoparticles (LNPs) largely rely on ionizable lipids to yield successful nucleic acid delivery via electrostatic disruption of the endosomal membrane. Here, we report the identification and evaluation of ionizable lipids containing a thiophene moiety (Thio-lipids). The Thio-lipids can be readily synthesized via the Gewald reaction, allowing for modular lipid design with functional constituents at various positions of the thiophene ring. Through the rational design of ionizable lipid structure, we prepared 47 Thio-lipids and identified some structural criteria required in Thio-lipids for efficient mRNA (messenger RNA) encapsulation and delivery in vitro and in vivo. Notably, none of the tested lipids have a pH-response profile like traditional ionizable lipids, potentially due to the electron delocalization in the thiophene core. Placement of the tails and localization of the ionizable headgroup in the thiophene core can endow the nanoparticles with the capability to reach various tissues. Using high-throughput formulation and barcoding techniques, we optimized the formulations to select two top lipids-20b and 29d-and investigated their biodistribution in mice. Lipid 20b enabled LNPs to transfect the liver and spleen, and 29d LNP transfected the lung and spleen. Unexpectedly, LNP with lipid 20b was especially potent in mRNA delivery to the retina with no acute toxicity, leading to the successful delivery to the photoreceptors and retinal pigment epithelium in non-human primates.

Intravitreal OZURDEX vs. Intravitreal Bevacizumab for Diabetic Macular Edema: A Comprehensive Review

This comprehensive review examines the efficacy, safety, and implications of intravitreal OZURDEX and intravitreal bevacizumab in treating diabetic macular edema (DME). DME is a common complication of diabetes mellitus and a leading cause of vision loss. OZURDEX, through sustained release of dexamethasone, targets inflammation and vascular permeability, while bevacizumab inhibits vascular endothelial growth factor (VEGF), reducing angiogenesis. However, differences in safety profiles exist, with OZURDEX associated with an increased risk of intraocular pressure elevation and cataract formation and bevacizumab potentially carrying systemic risks. The choice between these treatments should be individualized, considering patient preferences, ocular and systemic comorbidities, and cost-effectiveness. Collaboration among healthcare providers is essential for the comprehensive management of DME. Future research should focus on long-term comparative studies, predictors of treatment response, and exploration of novel therapeutic targets to optimize treatment outcomes for patients with DME.

Diagnosis, Treatment, and Prevention of Noninfectious Acute Anterior Uveitis with or without Human Leukocyte Antigen B27 in Adults - Expert Consensus in Taiwan

BACKGROUND

Anterior uveitis is the most common anatomical type of uveitis. Patients with noninfectious anterior uveitis may develop various ocular complications and eventually visual impairment. Appropriately differentiating the etiologies can help clinicians to predict the outcome, arrange clinical follow-up, and decide the treatment or prevention strategy. Adequate treatment and effective prevention strategies can reduce the frequency of recurrence and the risk of developing complications. Human leukocyte antigen (HLA)-B27 is the most common positive finding in patients with noninfectious AAU in many countries including Taiwan.

PURPOSE

To report a consensus from experienced uveitis specialists and rheumatologists was made in Taiwan.

METHODS

A panel of nine ophthalmologists from nine different referral centers with expertise in the management of uveitis and an experienced rheumatologist was held on January 16, 2022. A comprehensive literature review was performed. Differential diagnoses for etiologies, general treatments, and prevention strategies were discussed. Each statement in the consensus was made only if more than 70% of the experts agreed.

RESULTS

A flow chart and seven statements regarding the differential diagnoses for etiologies, treatments and preventions, and co-management with rheumatologists were included in the consensus.

CONCLUSIONS

This article discusses the general diagnosis, treatment, and prevention of noninfectious acute anterior uveitis, with or without HLA-B27, in adults for general ophthalmologists to improve overall outcomes of these patients.

Pars plana vitrectomy for retinal detachment using perfluoro-n-octane as intraoperative tamponade: a multicenter, randomized, non-inferiority trial

AIM

To evaluate the efficacy and safety of perfluoro-n-octane (PFO) for ophthalmic surgery versus F-Octane as an intraoperative tamponade in pars plana vitrectomy (PPV) in management of retinal detachment.

METHODS

This multicenter, prospective, randomized, double-masked, parallel-controlled, non-inferiority trial was conducted in three ophthalmology clinical centers in China. Patients with retinal detachment, who were eligible for PPV were consecutively enrolled. Participants were assigned to PFO for ophthalmic surgery or F-Octane for intraocular tamponade in a 1:1 ratio. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) measurement, and dilated fundus examination were performed preoperatively and at 1, 7±1, 28±3d postoperatively. The primary outcome was complete retinal reattachment rate at postoperative day one. The non-inferiority margin was set at 9.8%. The secondary outcomes included intraoperative retinal reattachment rate, and mean changes in IOP and BCVA from baseline to 1, 7±1, 28±3d postoperatively, respectively. Safety analyses were presented for all randomly assigned participates in this study.

RESULTS

Totally 124 eligible patients completed the study between Mar. 14, 2016 and Jun. 7, 2017. Sixty of them were randomly assigned to the PFO for ophthalmic surgery group, and 64 were assigned to the F-Octane group. Baseline characteristics were comparable between the two groups. Both groups achieved 100% retinal reattachment at postoperative day one (difference 0, 95%CI: -6.21% to 5.75%, P=1). The pre-defined noninferiority criterion was met. No significant difference was observed in intraoperative retinal reattachment rate (difference 1.77%, P=0.61), mean changes in IOP (difference 0.36, -0.09, 2.22 mm Hg at 1, 7±1, 28±3d postoperatively, with all P>0.05) and BCVA (difference 0.04, -0.02, 0.06 logMAR at 1, 7±1, 28±3d postoperatively, all P>0.05) between the two groups. No apparent adverse events related to the utilization of PFO were reported.

CONCLUSION

In patients with retinal detachment undergoing PPV, PFO for ophthalmic surgery is non-inferior to F-Octane as an intraocular tamponade, and both are safe and well-tolerated.

Effect of suprachoroidal triamcinolone on intraocular pressure: a systematic review and meta-analysis

Background

Triamcinolone acetonide is a synthetic corticosteroid with multiple ocular uses. Like other corticosteroids, it too is associated with ocular side effects such as increased intraocular pressure (IOP), glaucoma and cataracts. Suprachoroidal administration of triamcinolone is hoped to reduce the ocular side effects of the drug, especially rises in IOP. Our systematic review and meta-analysis aims to study this phenomenon.

Objectives

The purpose of this study was to evaluate the effect of suprachoroidal triamcinolone injections on IOP.

Design

Systematic review and meta-analysis.

Methods

We utilized the Medline, Scopus and Cochrane databases for this review. Studies published till June 2023, which fulfilled the eligibility criteria, were included. Studies in the English language with adult participants who were administered suprachoroidal triamcinolone without any concurrent intervention were included, whereas studies that did not report the mean and standard deviation for IOP were excluded. The outcome of interest was IOP at 1, 3 and 6 months post-suprachoroidal triamcinolone injection. IOP values from included studies were extracted onto Review Manager version 5.4 for analysis.

Results

Our search yielded 104 results, from which 22 papers were shortlisted for full-text screening. Finally, 12 studies were included in the analysis. Our analysis suggests a statistically significant increase in IOP in the first month after suprachoroidal triamcinolone injection but no significant differences at 3 and 6 months post-injection as compared to baseline.

Conclusion

Elevated IOP at 1 month post-injection must be considered when using suprachoroidal triamcinolone and adequate safety measures must be taken. However, the absence of a significant rise at 3 and 6 months post-injection indicates that this modality is safer than other existing drug delivery methods.

Trial registration

Registered with the Research Registry with the unique identifying number 'reviewregistry1656.' https://www.researchregistry.com/browse-the-registry#registryofsystematicreviewsmeta-analyses/registryofsystematicreviewsmeta-analysesdetails/648eefe65b6523002995eb21/.

Incident glaucoma and ocular hypertension after periocular and intravitreal steroid injections: a claims-based analysis

BACKGROUND/AIMS

This study aims to determine the incidence and risk of open-angle glaucoma or ocular hypertension (OHT) following ocular steroid injections using healthcare claims data.

METHODS

We retrospectively reviewed deidentified insurance claims data from the IBM MarketScan Database to identify 19 156 adult patients with no prior history of glaucoma who received ocular steroid injections between 2011 and 2020. Patient demographics and steroid treatment characteristics were collected. Postinjection glaucoma/OHT development was defined as a new diagnosis of glaucoma/OHT, initiation of glaucoma drops, and/or surgical or laser glaucoma treatment. Cox proportional hazards models were used to determine the risk of glaucoma/OHT development within 5 years after first steroid injection.

RESULTS

Overall, 3932 (20.5%) patients were diagnosed with new glaucoma/OHT, 3345 (17.5%) started glaucoma drops and 435 (2.27%) required a laser or surgical glaucoma procedure within 5 years of first steroid injection. Triamcinolone subconjunctival injections were associated with a lower risk of glaucoma/OHT development than retrobulbar or intravitreal steroid injections (p<0.001, HR 0.68, 95% CI 0.59 to 0.79), whereas the 0.59 mg fluocinolone acetonide intravitreal implant had the highest risk of glaucoma/OHT development (p=0.001, HR 2.01, 95% CI 1.34 to 3.02). The risk of glaucoma/OHT development was also higher for patients receiving multiple steroid injections (p<0.001), with the largest increase in risk occurring after three total steroid injections.

CONCLUSION

Patients receiving ocular steroid injections are at risk of developing glaucoma/OHT, even with no prior glaucoma/OHT diagnosis or treatment. Patients should be closely monitored for the development of glaucoma following ocular steroid injections, particularly in the setting of intravitreal and/or repeated steroid administration.

Retinoprotective compounds, current efficacy, and future prospective

Retinal dysfunction is the most common cause of vision loss in several retinal disorders. It has been estimated a great increase in these pathologies that are becoming more globally widespread and numerous over time, also supported by the life expectancy increment. Among different types of retinopathies, we can account some that share causes, symptoms, and treatment including diabetic retinopathy, age-related macular degeneration, glaucoma, and retinitis pigmentosa. Molecular changes, environmental factors, and genetic predisposition might be some of the main causes that drive retinal tissue to chronic inflammation and neurodegeneration in these retinopathies. The treatments available on the market contain compounds that efficiently ameliorate some of the important clinical features of these pathologies like stabilization of the intraocular pressure, reduction of eye inflammation, control of eye oxidative stress which are considered the major molecular mechanisms related to retinal dysfunction. Indeed, the most commonly used drugs are anti-inflammatories, such as corticosteroids, antioxidant, hypotonic molecules and natural neuroprotective compounds. Unfortunately, these drugs, which are fundamental to treating disease symptoms, are not capable to cure the pathologies and so they are not life-changing for patients. This review provided an overview of current treatments on the market, but more interestingly, wants to be a quick window on the new treatments that are now in clinical trials. Additionally, it has been here highlighted that the recent technical enhancement of the investigation methods to identify the various retinopathies causes might be used as a sort of "precise medicine" approach to tailor the identification of molecular pathways involved and potentially study a dedicated treatment for each patient. This approach includes the use of cutting-edge technologies like gene therapy and metabolomics.

Impact of postnatal steroids on peripheral avascular retina and severity of retinopathy of prematurity

BACKGROUND

We investigated the role of postnatal steroids on the severity of retinopathy of prematurity (ROP) and its impact on peripheral avascular retina (PAR).

METHODS

A retrospective cohort study of infants born at ≤32 weeks gestation and/or birth weight ≤1500 g. Demographics, the dose and duration of steroid treatment, and age when full retinal vascularization occurred were collected. The primary outcomes were the severity of ROP and time to full vascularization of the retina.

RESULTS

A total of 1695 patients were enrolled, 67% of whom received steroid therapy. Their birth weight was 1142 ± 396 g and gestational age was 28.6 ± 2.7 weeks. The total hydrocortisone-equivalent dose prescribed was 28.5 ± 74.3 mg/kg. The total days of steroid treatment were 8.9 ± 35.1 days. After correction for major demographic differences, infants who received a higher cumulative dose of steroids for a longer duration had a significantly increased incidence of severe ROP and PAR (P < 0.001). For each day of steroid treatment, there was a 3.2% increase in the hazard of the severe form of ROP (95% CI: 1.022-1.043) along with 5.7% delay in achieving full retinal vascularization (95% CI: 1.04-1.08) (P < 0.001).

CONCLUSION

Cumulative dose and duration of postnatal steroid use were independently associated with the severity of ROP and PAR. Thus, postnatal steroids should be used very prudently.

IMPACT

We report ROP outcomes in a large cohort of infants from two major healthcare systems where we have studied the impact of postnatal steroids on the severity of ROP, growth, and development of retinal vessels. After correcting our data for three major outcome measures, we show that high-dose postnatal steroids used for a prolonged duration of time are independently associated with severe ROP and delay in retinal vascularization. Postnatal steroids impact the visual outcomes of VLBW infants significantly, so their clinical use needs to be moderated.

Treatments for Ocular Diseases in Pregnancy and Breastfeeding: A Narrative Review

Pregnancy is a medical condition in which the physiological changes in the maternal body and the potential impact on the developing fetus require a cautious approach in terms of drug administration. Individual treatment, a thorough assessment of the extent of the disease, and a broad knowledge of the therapeutic options and different routes of administration of ophthalmic drugs are essential to ensure the best possible results while minimizing risks. Although there are currently several routes of administration of drugs for the treatment of eye diseases, even with topical administration, there is a certain amount of systemic absorption that must be taken into account. Despite continuous developments and advances in ophthalmic drugs, no updated data are available on their safety profile in these contexts. The purpose of this review is both to summarize the current information on the safety of ophthalmic treatments during pregnancy and lactation and to provide a practical guide to the ophthalmologist for the treatment of eye diseases while minimizing harm to the developing fetus and addressing maternal health needs.

Next-generation nanomaterials: advancing ocular anti-inflammatory drug therapy

Ophthalmic inflammatory diseases, including conjunctivitis, keratitis, uveitis, scleritis, and related conditions, pose considerable challenges to effective management and treatment. This review article investigates the potential of advanced nanomaterials in revolutionizing ocular anti-inflammatory drug interventions. By conducting an exhaustive analysis of recent advancements and assessing the potential benefits and limitations, this review aims to identify promising avenues for future research and clinical applications. The review commences with a detailed exploration of various nanomaterial categories, such as liposomes, dendrimers, nanoparticles (NPs), and hydrogels, emphasizing their unique properties and capabilities for accurate drug delivery. Subsequently, we explore the etiology and pathophysiology of ophthalmic inflammatory disorders, highlighting the urgent necessity for innovative therapeutic strategies and examining recent preclinical and clinical investigations employing nanomaterial-based drug delivery systems. We discuss the advantages of these cutting-edge systems, such as biocompatibility, bioavailability, controlled release, and targeted delivery, alongside potential challenges, which encompass immunogenicity, toxicity, and regulatory hurdles. Furthermore, we emphasize the significance of interdisciplinary collaborations among material scientists, pharmacologists, and clinicians in expediting the translation of these breakthroughs from laboratory environments to clinical practice. In summary, this review accentuates the remarkable potential of advanced nanomaterials in redefining ocular anti-inflammatory drug therapy. We fervently support continued research and development in this rapidly evolving field to overcome existing barriers and improve patient outcomes for ophthalmic inflammatory disorders.

0.2% Betamethasone Sodium Phosphate: A Multicenter, Randomized, Double-Masked Study to Compare Its Ocular Safety, Tolerability, and Efficacy to Vehicle in Cataract Surgery Subjects

Purpose

To compare the preservative-free corticosteroid 0.2% betamethasone sodium phosphate BID (SURF-201) to vehicle BID in patients undergoing routine cataract surgery.

Methods

Phase 2, multicenter, randomized (1:1 ratio), double-masked, vehicle-controlled, parallel-group study in patients scheduled for uncomplicated cataract surgery without the aid of a femtosecond laser. Subjects instilled topical medications for 16 days beginning the day before cataract surgery (Day -1), 1 dose administered at least 1 hour prior to cataract surgery (on Day 0) and 1 dose on the evening after cataract surgery, and then 2 doses administered each day through Day 15; patients were re-evaluated on Days 22 and 32 to ensure no rebound inflammation. Primary outcome was the difference in the proportion of subjects with anterior chamber cell (ACC) grade 0 between the two groups at Day 15. Secondary outcomes included pain scores and overall safety.

Results

There was a statistically significant difference (P=0.004) in the proportion of subjects in the SURF-201 treatment group with an ACC grade of 0 at Day 15 (n=22/39 [56.4%]) compared to subjects in the vehicle treatment group (n=9/43 [20.9%]). There was no statistically significant difference (P=0.528) in the proportion of subjects in the SURF-201 treatment group who had a visual analog scale pain score of 0 at Day 15 (n=35/38 [89.7%]) compared to subjects in the vehicle group (n=33/40 [82.5%]). A slightly higher incidence of adverse events occurred in subjects in the SURF-201 treatment group (n=27/40 [67.5%]) compared to the vehicle treatment group (n=23/43 [53.5%]).

Conclusion

SURF-201 is an effective topical, preservative-free corticosteroid when dosed BID for the treatment of postoperative inflammation and prevention of pain in a post-cataract population.

Unilateral Posterior Uveitis in a Patient Receiving Nivolumab for Malignant Melanoma

Patients using immunotherapies like immune checkpoint inhibitors (ICIs) can develop ocular immune-related adverse effects (irAEs). Nivolumab (Opdivo®;Bristol-Myers Squibb, New York, NY, USA) is a commonly used ICI used to treat malignancies. A 75-year-old woman presented to our eye clinic with sudden loss in vision in the right eye. She had started nivolumab monotherapy 10 days before the onset of symptoms for the treatment of melanoma. Examination showed low visual acuity (20/170) in the right eye with few reactive cells and macular oedema and swelling in the anterior and posterior segments, respectively. Optical coherence tomography (OCT) of the right eye showed intra-retinal and sub-retinal fluid and multiple hyperreflective inner retinal round foci in the areas of inflammation. The differential diagnoses were infectious uveitis, Vogt-Koyanagi-Harada-like syndrome or masquerade retinopathy. After a full work-up, the patient was diagnosed with unilateral posterior uveitis. The patient responded to topical steroid therapy with improved vision (20/30). Uveitis is listed as an adverse effect on the prescribing list of the drug Opdivo®. Although not reported before, our case demonstrated unilateral involvement. We thus recommend clinicians to be wary after complaints of side effects from their patients; ocular toxicities should be considered.

Suppressing Inflammation for the Treatment of Diabetic Retinopathy and Age-Related Macular Degeneration: Dazdotuftide as a Potential New Multitarget Therapeutic Candidate

Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are major causes of blindness globally. The primary treatment option for DME and neovascular AMD (nAMD) is anti-vascular endothelial growth factor (VEGF) compounds, but this treatment modality often yields insufficient results, and monthly injections can place a burden on the health system and patients. Although various inflammatory pathways and mediators have been recognized as key players in the development of DR and AMD, there are limited treatment options targeting these pathways. Molecular pathways that are interlinked, or triggers of multiple inflammatory pathways, could be promising targets for drug development. This review focuses on the role of inflammation in the pathogenesis of DME and AMD and presents current anti-inflammatory compounds, as well as a potential multitarget anti-inflammatory compound (dazdotuftide) that could be a candidate treatment option for the management of DME and AMD.

Topical Treatment for Retinal Degenerative Pathologies: A Systematic Review

The topical administration of medicines is the preferred route in ocular therapy, at least for the anterior segment of the eye. However, the eye's inherent functional and biological barriers all work against the active pharmaceutical ingredient (API) to efficiently reach the targeted retinal structures. The main objective of this article is to offer a systematic review of the scientific literature in recent years, focusing on the latest developments of topical treatment intended for retinal degenerative diseases. Database search returned 102 clinical studies, focused on topical treatment for age macular degeneration, macular edemas (in diabetic retinopathy, surgery related or in retinal dystrophies) or glaucoma. After the exclusion of low-powered studies and those combining vitreo-retinal surgery, 35 articles remained for analysis. Currently, the topical treatment of retinal degenerative diseases is limited by the difficulty to deliver effective drug concentrations to the posterior eye structures. However, in the case of drug classes like NSAIDs, the presence of certain molecular and metabolic features for specific representatives makes the topical administration currently feasible in several clinical contexts. For other drug classes, either a fine-tuning of the API's pharmacokinetic profile or the use of more advanced formulation strategies, such as rationally designed nanostructured drugs and vehicles, crystalline polymorphs or supramolecular complexes, could bring the much awaited breakthrough for a more predictable and controlled delivery towards the retinal structures and could eventually be employed in the future for the development of more effective ways of delivering drugs to the posterior eye, with the ultimate goal of improving their clinical efficacy.

Epidemiology and Economic Cost Analysis of Microbial Keratitis from a Tertiary Referral Hospital in Australia

Microbial keratitis is the most common cause of infective vision loss. The causative organism varies by region, and most cases require intensive antimicrobial therapy. The purpose of this study was to analyse the causative organisms of microbial keratitis, its presentation and economic burden from a tertiary referral hospital in Australia. A retrospective review of 160 cases of microbial keratitis was performed, over a 5-year period from 2015–2020. A wide variety of costs were considered to determine the economic burden, using standardized data from the Independent Hospital Pricing Authority and the cost of personal income loss. Our study showed the most commonly occurring pathogens were Herpes Simplex (16%), Staphylococcus aureus (15.1%) and Pseudomonas aeruginosa (14.3%). A total of 59.3% of patients were admitted, with a median length of admission of 7 days. Median cost for all presentations of microbial keratitis was AUD 8013 (USD 5447), with costs significantly increasing with admission. The total annual cost of microbial keratitis within Australia is estimated to be AUD 13.58 million (USD 9.23 million). Our findings demonstrate that microbial keratitis represents a significant economic burden for eye-related diseases and the key driving factor for the cost is the length of admission. Minimizing the duration of admission, or opting for outpatient management where appropriate, would significantly reduce the cost of treatment for microbial keratitis.

Combined intravitreal dexamethasone and bevacizumab injection for the treatment of persistent diabetic macular edema (DexaBe study): a phase I clinical study

PURPOSE

The aim of this study is to investigate the safety of combined intravitreal injection of dexamethasone aqueous-solution (IVD) and bevacizumab (IVB) in patients with refractory diabetic macular edema (DME) and its effect on intraocular pressure (IOP), best-corrected visual acuity (BCVA) and central subfield thickness (CSFT).

METHODS

This prospective study included 10 patients (10 eyes) with DME refractory to laser photocoagulation and/or anti-vascular endothelial growth factor (anti-VEGF) therapy. A complete ophthalmological examination was performed at baseline, during the first week of treatment, and monthly through week 24. Therapy consisted of monthly injections of combined IVD and IVB "pro re nata" (PRN) if CST > 300 µm. We investigated the impact of the injections on intraocular pressure (IOP), cataract development, Early Treatment Diabetic Retinopathy Study (ETDRS) best corrected visual acuity (BCVA), and central sub-foveal thickness (CSFT) measured by spectral-domain optical coherence tomography (OCT).

RESULTS

Eight patients (80%) completed 24 weeks of follow-up. Compared to baseline, mean IOP increased significantly (p < 0.05) and anti-glaucomatous eye drops were necessary for 50% of the patients, CSFT was significantly reduced at all follow-up visits (p < 0.05), although mean BCVA showed no significant improvement. One patient developed dense cataract progression and another showed vitreoretinal traction at week 24. No inflammation or endophthalmitis was observed.

CONCLUSION

Treatment of DME refractory to laser and/or anti-VEGF therapy with combined PRN IV dexamethasone aqueous solution and bevacizumab was associated with adverse effects related to the use of corticosteroids. However, there was a significant improvement in CSFT meantime best-correct visual acuity remained stable or improved in 50% of patients.

Discovery and Preclinical Development of Novel Intraocular Pressure-Lowering Rho Kinase Inhibitor: Corticosteroid Conjugates

Purpose: A new class of ocular steroids designed to mitigate steroid-induced intraocular pressure (IOP) elevation while maintaining anti-inflammatory activity was developed. Herein is described the discovery and preclinical characterization of ROCK'Ster compound 1. Methods: Codrugs consisting of a Rho kinase inhibitor (ROCKi) and a corticosteroid were synthesized. Compounds were initially screened in vitro for ROCKi activity and anti-inflammatory activity against the proinflammatory interleukin 23 and bacterial lipopolysaccharide (LPS) pathways. Selected compounds were then screened for solubility, chemical stability, and ex vivo corneal metabolism. Lead compound 1 was evaluated for IOP lowering in the Dutch Belted rabbit and for anti-inflammatory efficacy in both a postcataract surgery model and an allergic eye disease (AED) mouse model. Results: Several ROCK'Sters were found to be potent inhibitors of ROCK (K_is < 50 nM), have high anti-inflammatory activity in vitro (IC₅₀s < 50 nM), display sufficient stability in topical ophthalmic formulations, and have a moderate rate of corneal metabolism. Compound 1 (0.1% and 0.25%, quater in die [QID]-4 times a day) demonstrated IOP-lowering capability without inducing hyperemia in our rabbit model. When compared with the marketed steroids, Durezol^® and Pred Forte^®, compound 1 (0.1%, 0.25%) demonstrated noninferiority in clinical scoring in a rabbit model of inflammation after surgery. In addition, anti-inflammatory outcomes were observed with compound 1 (0.1%) relative to Lotemax^® or vehicle control in an AED mouse model. Conclusion: ROCK'Ster compound 1 is a novel compound suitable for topical ocular dosing that possesses IOP-lowering capability along with similar anti-inflammatory activity compared with marketed steroids.

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.

Central serous chorioretinopathy: A review

Central serous chorioretinopathy (CSC) is the fourth most common non-surgical retinopathy associated with fluid leakage. The pathogenesis is not yet completely understood, but changes in the choroid, sclera and RPE have been described associated with venous congestion of choroidal outflow. CSC can be categorised into acute, chronic, and recurrent subtypes with recent classifications of simple and complex based on the area of RPE change seen on fundus autofluorescence. A multimodal imaging approach is helpful in the diagnosis and management of CSC and secondary complications such as type 1 neovascularisation. Although spontaneous resolution with relatively good visual outcomes is common, treatment should be considered in patients with persistent or recurrent SRF. Treatment options include laser, systemic medications, intravitreal therapy, and surgery. Of these, argon laser for focal extramacular fluid leaks and photodynamic therapy of leakage identified by indocyanine-green angiography currently have the greatest supportive evidence.

Management of inflammation after the cataract surgery

PURPOSE OF REVIEW

To review most recent studies and clinical trials regarding pathogenesis, treatment, and prevention of inflammation after the cataract surgery.

RECENT FINDINGS

FLACS gave opportunity to evaluate inflammatory cytokines in the aqueous humour right after the laser procedure, which led to acknowledging the inflammation pathogenesis during the phacoemulsification. Although there is still a lack of evidence, which would prove the long-term benefit of NSAIDs, they are indicated and effective when risk factors for PCME are present. PREMED studies showed that combination of NSAID and steroids after the surgery for healthy subjects is cost-effective. The triamcinolone injection together with topical steroids and NSAIDs for diabetic patients after the cataract surgery was the most cost-effective in preventing PCME according to the PREMED. Dropless cataract surgery is another emerging topic: dexamethasone implants and suspensions look promising as we await more clinical trials with drug-loaded IOLs.

SUMMARY

Inflammation after the cataract surgery can be prevented, and these methods are one of the most essential topics with growing phacoemulsification rate. Topical NSAIDs are cost-effective not only for patients with risk factors for PCME but also for healthy subjects. New dropless techniques are being successfully introduced in the clinical practice.

Bilateral Cystoid Macular Edema with Zanubrutinib Therapy: A Case Report

We present a patient with recurrent mantle cell lymphoma (MCL) who was treated with zanubrutinib, a Bruton's tyrosine kinase inhibitor. He subsequently developed bilateral cystoid macular edema (CME) in both eyes. This is the first report of CME in a patient with MCL who was treated with zanubrutinib. CME was refractory to topical corticosteroid therapy, but sub-Tenon's steroid injections and holding off zanubrutinib managed to decrease the CME. Treatment managed to prevent further vision loss but did not restore lost vision. The prompt ophthalmic exam is recommended for patients on zanubrutinib with decreased vision.

Retrospective Study of a Sustained-Release Intracanalicular Dexamethasone Insert for Treatment of Ocular Inflammation After Cataract and Corneal Surgery

PURPOSE

To evaluate the effectiveness and safety of a sustained-release intracanalicular dexamethasone insert (Dextenza, Ocular Therapeutix, Inc.) as an adjunctive therapy in patients undergoing cataract and corneal surgery.

PATIENTS AND METHODS

This retrospective case series contains 18 patients undergoing cataract surgery and 6 patients undergoing corneal surgery. All patients received the Dextenza intracanalicular insert. 6/18 of the patients in the cataract surgery arm were on the standard of care post-surgery topical steroid drop regimen, whereas 11/18 of the patients were on a reduced regimen. 1/18 of the patients was on a drop regimen that deviated from the aforementioned regimens. 2/6 of the patients in the corneal surgery arm were on the standard of care post-surgery topical steroid drop regimen, whereas 3/6 of the patients were on a reduced regimen. 1/6 of the patients were on a drop regimen that deviated from the aforementioned regimens.

RESULTS

The primary outcome measures are intraocular pressure (IOP) levels and anterior chamber inflammation levels across the post-operative recovery period. 1/18 of the patients in the cataract surgery arm and 1/6 of the patients in the corneal surgery arm experienced a clinically significant IOP spike greater than 10 millimeters of mercury (mmHg) above baseline IOP. No patient in either of the study groups had significant inflammation after 1 week post-surgery. 1/18 of the patients in the cataract surgery arm and 1/6 of the patients in the corneal surgery arm experienced a canalicular obstruction.

CONCLUSION

Dextenza with the lower drop protocol showed non-inferiority in terms of inflammation management and safety. As with any steroid delivery mechanism, monitoring IOP is paramount when using Dextenza. One of the patients with a canalicular obstruction had a history of punctal plug implantation, so care should be taken when choosing to implant Dextenza in such a patient.

Triamcinolone acetonide injectable suspension for suprachoroidal use in the treatment of macular edema associated with uveitis

Introduction

Macular edema due to noninfectious uveitis is a sight-threatening complication that is routinely treated with corticosteroids. Triamcinolone acetonide injectable suspension for suprachoroidal use (Xipere™) is an alternative treatment option for patients with non-infectious uveitis associated macular edema.

Areas covered

This review describes the recently FDA approved triamcinolone acetonide injectable suspension that can be injected into the suprachoroidal space. This physiological space is between the sclera and choroid. This allows for therapeutic targeting of the retina and choroid. This review highlights published clinical trials for this novel drug preparation.

Expert opinion

Suprachoroidal administration of triamcinolone acetonide has shown improvement in vision and inflammation in studies with non-infectious uveitis associated macular edema. This unique delivery method suggests the potential to decrease side effects of anterior segment exposure such as glaucoma and cataract, but head-to-head trials are needed for further study of safety and efficacy. Additionally, there are promising prospective studies underway for utilization of the suprachoroidal space for other diseases including macular degeneration, diabetic macular edema, and ocular tumors.

Advances in ophthalmic drug delivery technology for postoperative management after cataract surgery

INTRODUCTION

Cataract surgery is becoming more common due to an aging world population. Intraocular lenses and surgical technique have developed remarkably recently, but the development of postoperative medication to prevent postsurgery complications has been relatively delayed. We still largely depend on eye drops for the management of post-cataract-surgery patients. Mental and physical problems that often occur in elderly cataract patients make it difficult for patients to apply eye drops by themselves. It is necessary to develop new effective drug delivery methods.

AREAS COVERED

This updated review article provides a brief review of why drug management is needed following cataract surgery and an overview of current developments in new drug delivery methods for ophthalmic treatment. In particular, various novel drug delivery methods that can be used for post-cataract-surgery management and their current development stages are extensively reviewed.

EXPERT OPINION

Rapidly developing technologies, such as intraocular and external ophthalmic implants, polymers, and nanotechnology, are being actively applied to develop novel drug delivery systems for safe and effective management after cataract surgery. Their goal is to achieve sufficient drug release for the desired duration with a single application. These will largely replace the inconvenience of eye drops for elderly patients in the future.

Importance of Corneal Angiography in Subclinical Limbitis in a Case of Atopic Keratoconjunctivitis

PURPOSE

The aim of this study was to report corneal angiography features in subclinical limbitis in a patient with atopic keratoconjunctivitis.

METHODS

This is a case report.

RESULTS

A 22-year-old woman with a medical history of atopic keratoconjunctivitis was referred for bilateral corneal neovascularization with scarring. On examination, no signs of active disease were noticed at the slit lamp. Ocular surface angiography detected active corneal limbitis, showing as limbal leakage at fluorescein angiography in the early phase and leakage after indocyanine green angiography in the late phase. The patient was treated with topical corticosteroid. At follow-up, the fluorescein angiography and indocyanine green angiography no longer showed limbal leakage, whereas the slit lamp examination was unchanged.

CONCLUSIONS

Active allergic corneal limbitis may present as subclinical inflammation, with no signs of activity at the slit lamp examination. Therefore, its diagnosis can be challenging without the use of corneal angiography.

Inflammation-targeted sialic acid-dexamethasone conjugates for reducing the side effects of glucocorticoids

As a potent glucocorticoid drug (GCs), Dexamethasone (Dex) is widely used clinically for the treatment of inflammatory diseases. However, such side effects as Cushing's syndrome and osteoporosis caused severe distress to patients. Herein, a sialic acid (SA)-modified dexamethasone conjugate (Dex-SA) was synthesized successfully to reduce side effects by targeting inflammatory diseases. The solubility of Dex-SA in water reached 58 times that of Dex, which meets the need for intravenous administration. The excellent stability of Dex-SA in plasma also laid a foundation for targeting disease sites. According to cellular uptake and biodistribution experiments, Dex-SA was more readily to be taken up by inflammatory cells and accumulated in diseased kidneys compared to Dex, which is attributed to the interaction of SA with E-selectin receptors overexpressed on the surface of inflammatory vascular endothelial cells. Besides, the pharmacodynamics studies of acute kidney injury showed that Dex-SA and Dex could produce comparable therapeutic effects. More importantly, Dex-SA was found to significantly reduce Dex-related side effects, as measured by blood glucose, red blood cells and immune cells, etc. At last, molecular docking results were obtained to confirm that Dex-SA could enter the cells by binding specifically with the E-selectin receptor, for combination with glucocorticoid receptors in the cytoplasm to exert pharmacological effects. Our study is expected to contribute a new strategy to the safe and effective targeting treatment of inflammatory diseases.

Lycium barbarum polysaccharide promotes corneal Re-epithelialization after alkaline injury

Chemical injury of the cornea results in epithelial defect and subsequent stromal scarring and infection. Our study aims to evaluate the effectiveness of pre-treatment of Lycium barbarum polysaccharide (LBP) in promoting corneal re-epithelialization after alkaline burn. The corneas of C57BL/6J mice were pre-treated with topical phosphate-buffered saline or LBP (0.2/2/20 mg/mL) for 7 days, following by 0.1M sodium hydroxide injury for 30 s and washing with distilled water for another 30 s. Area of epithelial defect and thickness of cornea were evaluated. Inflammatory cytokines and water channel expression levels were assessed using immunohistochemistry and Western blot. Compared to the injury group, mice with 2 mg/mL LBP pre-treatment revealed a significant decrease in fluorescein stained area after injury (p = 0.025), with increased epithelial layer thickness (p = 0.004). The corneal opacity was significantly reduced in the group with 2 mg/mL LBP pre-treatment followed by injury (p = 0.02). The expression of matrix metalloproteinase 12 (p = 0.033), platelet derived growth factor-BB (p = 0.031), and aquaporin 5 (p = 0.022) resulted in a decrease in expression level in group with 2 mg/mL LBP pre-treatment. Our results showed that 2 mg/mL LBP, with no apoptotic effect on corneal cells, promoted corneal epithelial growth and minimized disruption of the collagen architecture after injury in vivo. We suggest that LBP, as a natural Traditional Chinese Medicine, may potentially be a novel topical pre-treatment option for patients highly susceptible to ocular injury.

Treatment of Macular Edema in Vascular Retinal Diseases: A 2021 Update

Macular edema (ME) is associated with various conditions; however, the main causes of ME are retinal vein occlusion (RVO) and diabetes. Laser photocoagulation, formerly the gold standard for the treatment of ME, has been replaced by anti-vascular endothelial growth factor (anti-VEGF) intravitreal injections. Despite its efficiency, this treatment requires frequent injections to preserve the outcomes of anti-VEGF therapy, and as many patients do not sufficiently respond to the treatment, ME is typically a chronic condition that can lead to permanent visual impairment. Generalized recommendations for the treatment of ME are lacking, which highlights the importance of reviewing treatment approaches, including recent anti-VEGFs, intravitreal steroid implants, and subthreshold micropulse lasers. We reviewed relevant studies, emphasizing the articles published between 2019 and 2021 and using the following keywords: macular edema, diabetic macular edema, retinal vein occlusion, laser photocoagulation, anti-VEGF, and intravitreal injections. Our results revealed that a combination of different treatment methods may be beneficial in resistant cases. Additionally, artificial intelligence (AI) is likely to help select the best treatment option for patients in the near future.

Dose identification of triamcinolone acetonide for noninvasive pre-corneal administration in the treatment of posterior uveitis using a rapid, sensitive HPLC method with photodiode-array detector

Triamcinolone acetonide (TAA) is the drug of choice in the management of ocular inflammations due to its anti-inflammatory and immuno-suppressant activity. Available marketed formulations (Triesence, Trivaris, Kenalog) are in the suspension form recommended to be administered via intravitreal injection, which has many major complications. In the present study, we have designed and evaluated Hydroxypropyl-β-cyclodextrin (HP-β-CD),) based conventional formulations of TAA (aqueous suspensions) with different dose strengths to identify the dose strength required for achieving the effective concentrations in vitreous humor following pre-corneal administration of the formulations. Ocular pharmacokinetic studies of conventional formulations of triamcinolone acetonide (TAA) with different dose strengths (1 mg/30µL, 2 mg/30µL, 4 mg/30µL) were performed to identify the dose strength required to produce effective concentrations of TAA in the aqueous and vitreous humor. A rapid, sensitive, selective, accurate and precise bioanalytical method utilizing a small sampling volume (<45 µL) was developed and validated for quantification of TAA in the samples obtained from the ocular pharmacokinetic studies. Aqueous suspensions of TAA with 20% HP-β-CD produced time course profiles in the aqueous humor at all the dose strengths. However, measurable concentrations and time course of TAA in vitreous humor were achieved only with 4 mg/30µL dose strength.

Corticosteroids in the Management of Infectious Keratitis: A Concise Review

Microbial keratitis is devastating corneal morbidity with a variable spectrum of clinical manifestations depending on the infective etiology. Irrespective of the varied presentation delayed treatment can lead to severe visual impairment resulting from corneal ulceration, possible perforation, and subsequent scarring. Corticosteroids with a potent anti-inflammatory activity reduce host inflammation, thus minimizing resultant scarring while improving ocular symptoms. These potential effects of corticosteroids have been applied widely to treat various corneal diseases ranging from vernal keratoconjunctivitis to dry eye disease. However, antimicrobial therapy remains the mainstay of treatment in microbial keratitis, whereas the use of adjunctive topical corticosteroid therapy remains a matter of debate. Understandably, the use of topical corticosteroids is a double-edged sword with pros and cons in the treatment of microbial keratitis. Herein we review the rationale for and against the use and safety of topical corticosteroids in the treatment of infective keratitis. Important considerations, including type, dose, efficacy, the timing of initiation of corticosteroids, use of concomitant antimicrobial agents, and duration of corticosteroid therapy while prescribing corticosteroids for microbial keratitis, have been discussed. This review intends to provide new insights into the therapeutic utility of steroids as adjunctive treatment of corneal ulcer.

TRENDS IN INTRAVITREAL CORTICOSTEROID AGENT USE BY US OPHTHALMOLOGISTS IN MEDICARE BENEFICIARIES AND ASSOCIATION WITH PHYSICIAN-INDUSTRY INTERACTIONS

PURPOSE

To report trends of intravitreal corticosteroid use and explore the relationship between career experience, reported industry payments, and prescribing habits.

METHODS

A retrospective review of ophthalmologists who administered intravitreal dexamethasone implants (DEX) and triamcinolone acetonide (TA) injections between August 2013 and December 2017.

RESULTS

A total of 1,070 US ophthalmologists were reimbursed by Medicare for 522,804 DEX injections and 2.6 million TA injections. There was a significant positive trend in the number of DEX (P = 0.01), but not TA, injections per year. Mid-career and late-career physicians performed significantly greater total injections on average compared with early-career physicians (both P < 0.001). Early-career physicians performed a greater proportion of DEX injections than late-career physicians (P = 0.006). Industry payments were positively associated with the proportion of DEX used and inversely correlated with the proportion of TA administered (P < 0.001). On multivariate analysis, years in practice, number of payments, and total value of payments were significantly associated with the number of DEX injections administered (all P < 0.001).

CONCLUSION

From 2013 to 2017, the use of DEX increased, whereas TA use remained stable. There was a positive association between DEX use and physician-industry interactions, which may be explained by seniority and experience. This study does not define a causal relationship.

Guidelines for the Management of Center-Involving Diabetic Macular Edema: Treatment Options and Patient Monitorization

Diabetic macular edema (DME) is the main cause of visual impairment associated with diabetic retinopathy (DR) and macular laser, during approximately three decades, and was the single treatment option. More recently, intravitreous injections of anti-angiogenics and corticosteroids modified the treatment paradigm associated with significant vision improvements. Nevertheless, not all patients respond satisfactorily to anti-VEGF or corticosteroid injections, so an adequate treatment choice and a prompt switch in therapeutic class is recommended. Several algorithms and guidelines have been proposed for treating center involving DME to improve patients’ vision and quality of life. However, in Portugal, such guidelines are lacking. The present review aimed to provide guidelines for the treatment options and patient monitorization in the management of center-involving DME. We recommend anti-vascular endothelial growth factor (VEGF) as first-line therapy after a clinical evaluation accompanied by a rigorous metabolic control. Depending on the response obtained after 3–6 monthly intravitreal injections we suggest switching outside the class in case of a non-responder, maintaining the anti-VEGF-therapy in responders to anti-angiogenics. The treatment regimen for Dexamethasone intravitreal implant (DEXii) should be pro-re-nata with bi-monthly or quarterly monitoring visits (with a scheduled visit at 6–8 weeks after DEXii for intraocular pressure control). If a patient does not respond to DEXii, switch again to anti-VEGF therapy, combine therapies, or re-evaluate patients diagnose. There is a resilient need to understand the disease, its treatments, regimens available, and convenience for all involved to propose an adequate algorithm for the treatment of diabetic retinopathy (DR) and DME in an individualized regimen. Further understanding of the contributing factors to the development and progression of DR should bring new drug discoveries for more effective and better-tolerated treatments.

Polymer-free corticosteroid dimer implants for controlled and sustained drug delivery

Polymeric drug carriers are widely used for providing temporal and/or spatial control of drug delivery, with corticosteroids being one class of drugs that have benefitted from their use for the treatment of inflammatory-mediated conditions. However, these polymer-based systems often have limited drug-loading capacity, suboptimal release kinetics, and/or promote adverse inflammatory responses. This manuscript investigates and describes a strategy for achieving controlled delivery of corticosteroids, based on a discovery that low molecular weight corticosteroid dimers can be processed into drug delivery implant materials using a broad range of established fabrication methods, without the use of polymers or excipients. These implants undergo surface erosion, achieving tightly controlled and reproducible drug release kinetics in vitro. As an example, when used as ocular implants in rats, a dexamethasone dimer implant is shown to effectively inhibit inflammation induced by lipopolysaccharide. In a rabbit model, dexamethasone dimer intravitreal implants demonstrate predictable pharmacokinetics and significantly extend drug release duration and efficacy (>6 months) compared to a leading commercial polymeric dexamethasone-releasing implant.

Dexamethasone Conjugates: Synthetic Approaches and Medical Prospects

Dexamethasone (DEX) is the most commonly prescribed glucocorticoid (GC) and has a wide spectrum of pharmacological activity. However, steroid drugs like DEX can have severe side effects on non-target organs. One strategy to reduce these side effects is to develop targeted systems with the controlled release by conjugation to polymeric carriers. This review describes the methods available for the synthesis of DEX conjugates (carbodiimide chemistry, solid-phase synthesis, reversible addition fragmentation-chain transfer [RAFT] polymerization, click reactions, and 2-iminothiolane chemistry) and perspectives for their medical application as GC drug or gene delivery systems for anti-tumor therapy. Additionally, the review focuses on the development of DEX conjugates with different physical-chemical properties as successful delivery systems in the target organs such as eye, joint, kidney, and others. Finally, polymer conjugates with improved transfection activity in which DEX is used as a vector for gene delivery in the cell nucleus have been described.

Development of a dual delivery of levofloxacin and prednisolone acetate via PLGA nanoparticles/ thermosensitive chitosan-based hydrogel for postoperative management: An in-vitro and ex-vivo study

Post-operative endophthalmitis (POE) is one of the most dreadful complications after intraocular surgery. For cataract surgery patients, both commercially available topical 0.5% levofloxacin and 1% prednisolone acetate (PA) ophthalmic solution require at least 3 to 4 times application daily. In this study, we develop a dual drug delivery system composed of the thermosensitive chitosan/gelatin-based hydrogel containing PA and levofloxacin-loaded nanoparticles (LNPs). LNPs with negative surface charge show the monodisperse (polydispersity index ~0.045), nanosize (~154.7 nm) and sphere-like structure. The optimal concentration of LNPs and PA to corneal epithelial cells was 5 μg/mL and 50 μg/mL, respectively. The developed dual drug delivery system (PAgel-LNPs) could gel at 34 °C within 63 s. The osmolarity of PAgel-LNPs was 301.2 ± 1.5 mOsm/L. PAgel-LNPs showed a sustained-release profile for 7 days. Post-treatment of PAgel-LNPs in TNF-α-damaged corneal epithelial cells could decrease the inflammation (inflammatory genes (TNF-α, IL-6, MMP-3 andMMP-9) and IL-6 production) and cell death. In ex-vivo rabbit model of S. aureus keratitis, the anti-inflammation and anti-bacterial property have been demonstrated. These results suggest that thermosensitive PAgel-LNPs may have the potential to use for the prevention of POE.

Dexamethasone PLGA Microspheres for Sub-Tenon Administration: Influence of Sterilization and Tolerance Studies

Many diseases affecting the posterior segment of the eye require repeated intravitreal injections with corticosteroids in chronic treatments. The periocular administration is a less invasive route attracting considerable attention for long-term therapies. In the present work, dexamethasone-loaded poly(lactic-co-glycolic) acid (PLGA) microspheres (Dx-MS) were prepared using the oil-in-water (O/W) emulsion solvent evaporation technique. MS were characterized in terms of mean particle size and particle size distribution, external morphology, polymer integrity, drug content, and in vitro release profiles. MS were sterilized by gamma irradiation (25 kGy), and dexamethasone release profiles from sterilized and non-sterilized microspheres were compared by means of the similarity factor (f₂). The mechanism of drug release before and after irradiation exposure of Dx-MS was identified using appropriate mathematical models. Dexamethasone release was sustained in vitro for 9 weeks. The evaluation of the in vivo tolerance was carried out in rabbit eyes, which received a sub-Tenon injection of 5 mg of sterilized Dx-MS (20–53 µm size containing 165.6 ± 3.6 µg Dx/mg MS) equivalent to 828 µg of Dx. No detectable increase in intraocular pressure was reported, and clinical and histological analysis of the ocular tissues showed no adverse events up to 6 weeks after the administration. According to the data presented in this work, the sub-Tenon administration of Dx-MS could be a promising alternative to successive intravitreal injections for the treatment of chronic diseases of the back of the eye.

Corneal Refractive Surgery in Patients with a History of Herpes Simplex Keratitis: A Narrative Review

The incidence of herpes simplex keratitis (HSK) in patients following corneal refractive surgery is higher than in the general population, and several case reports of ocular morbidity in HSK infection following corneal refractive surgery have been published. HSK is listed by the American Academy of Ophthalmology as a relative contraindication to corneal refractive surgery, although specifics have not been further elucidated. This review summarizes the current literature regarding reactivation of HSK following corneal refractive surgery and provides a guideline for considering corneal refractive surgery in a patient with a previous history of HSK. Based on the current literature, we recommend that corneal refractive surgery is appropriate for patients with a history of HSK without multiple recurrences who have had no evidence of disease for at least one year. In addition to a thorough history and physical examination, we also recommend these patients begin 400 mg twice daily of oral acyclovir or valacyclovir 500 mg once daily for two weeks prior to surgery and continue this regimen for at least two weeks postoperatively or while on topical steroids.

Blockade of Retinal Oscillations by Benzodiazepines Improves Efficiency of Electrical Stimulation in the Mouse Model of RP, rd10

Purpose

In RP, photoreceptors degenerate. Retinal prostheses are considered a suitable strategy to restore vision. In animal models of RP, a pathologic rhythmic activity seems to compromise the efficiency of retinal ganglion cell stimulation by an electrical prosthesis. We, therefore, strove to eliminate this pathologic activity.

Methods

Electrophysiologic recordings of local field potentials and spike activity of retinal ganglion cells were obtained in vitro from retinae of wild-type and rd10 mice using multielectrode arrays. Retinae were stimulated electrically.

Results

The efficiency of electrical stimulation was lower in rd10 retina than in wild-type retina and this was highly correlated with the presence of oscillations in retinal activity. Glycine and GABA, as well as the benzodiazepines diazepam, lorazepam, and flunitrazepam, abolished retinal oscillations and, most important, increased the efficiency of electrical stimulation to values similar to those in wild-type retina.

Conclusions

Treatment of patients with these benzodiazepines may offer a way to improve the performance of retinal implants in cases with poor implant proficiency. This study may open the way to a therapy that supports electrical stimulation by prostheses with pharmacologic treatment.

Local delivery of corticosteroids in clinical ophthalmology: A review

Locally administered steroids have a long history in ophthalmology for the treatment of inflammatory conditions. Anterior segment conditions tend to be treated with topical steroids whilst posterior segment conditions generally require periocular, intravitreal or systemic administration for penetration. Over recent decades, the clinical applications of periocular steroid delivery have expanded to a wide range of conditions including macular oedema from retino-vascular conditions. Formulations have been developed with the aim to provide practical, targeted, longer-term and more efficacious therapy whilst minimizing side effects. Herein, we provide a comprehensive overview of the types of periocular steroid delivery, their clinical applications in ophthalmology and their side effects.