Demodex Blepharitis Treated with a Novel Dilute Povidone-Iodine and DMSO System: A Case Report

Latest developments on meibomian gland dysfunction: Diagnosis, treatment and management

Background: Meibomian gland dysfunction (MGD) is one of the leading causes of evaporative dry eye disease and one of the most common ophthalmic conditions found in clinical practice. Meibomian gland dysfunction tends to be overlooked because its signs and symptoms do not cause blindness. Meibomian gland dysfunction is characterised by the obstruction of the meibomian gland terminal ducts resulting in tear film instability.Aim: The purpose of this article was to provide an update on MGD’s diagnosis and treatment.Method: A literature review was conducted using search engines such as Google Scholar, Medline and ScienceDirect databases. Keywords such as MGD diagnosis and management and treatment of MGD were used to search the databases.Results: A total of 44 relevant papers were reviewed. These papers were then curated to include only those concerning diagnosis of meibomian gland dysfunction, treatment of meibomian gland dysfunction and management options of meibomian gland dysfunction. The references of individual papers from the curated results were checked to yield a further 13 papers.Conclusion: Meibomian gland dysfunction is not a single entity but is multifactorial in origin; however, our understanding of the condition is evolving rapidly because of newer imaging technology. There is no gold standard treatment option for MGD, but many options are available that include medications and other procedures. 

In vitro larvicidal activity of ivermectin and povidone-iodine against Oestrus ovis

Purpose

To assess the in vitro larvicidal activity of ivermectin and povidone-iodine (PVP-I) against Oestrus ovis, the most frequent cause of external ophthalmomyiasis.

Methods

L1 O. ovis larvae were collected from the nasal boots of sheep slaughtered in local abattoirs and transferred onto Petri dishes containing mucosal tissue (25 larvae/dish). The larvicidal activity of the following formulations was tested: 1% ivermectin suspension in balanced sterile saline solution (BSSS), 1% ivermectin solution in propylene glycol, propylene glycol, 0.6% PVP-I in hyaluronic acid vehicle (IODIM®), and combination of ivermectin 1% solution and 0.6% PVP-I. One mL of each formulation was added to different Petri dishes containing the larvae. The time needed to kill the larvae was recorded.

Results

893 larvae were tested. The median time needed to kill the larvae was 46, 44, 11, 6, and 10 minutes for Iodim®, ivermectin 1% suspension, propylene glycol, ivermectin 1% solution, and a combination of ivermectin 1% solution with 0.6% PVP-I, respectively. Kaplan-Meyer analysis disclosed that the survival curves were significantly lower in samples treated with ivermectin 1% solution, ivermectin 1% solution + 0.6% PVP-I, and propylene glycol than in samples receiving other treatments or BSSS.

Conclusion

In this in vitro study, ivermectin 1% solution in propylene glycol, ivermectin 1% solution + 0.6% PVP-I, and propylene glycol alone showed a good, relatively rapid larvicidal activity against O. ovis larvae. Further experimental and clinical studies are necessary to establish whether, or not, these formulations may be considered as potential candidates for the topical treatment for external ophthalmomyiasis caused by O. ovis.

Infectious Keratitis After Boston Type 1 Keratoprosthesis Implantation

PURPOSE

To identify the incidence, risk factors, and outcomes of infectious keratitis after Boston type 1 keratoprosthesis (kpro) implantation.

METHODS

Retrospective case series of kpro procedures at the Stein Eye Institute and the Centre Hospitalier de l'Université de Montréal between May 1, 2004, and December 31, 2018. Data were collected regarding ocular history, operative details, postoperative management, microbiologic profile, treatment, and outcomes. Log-rank test and Cox proportional hazard ratio (HR) were used to evaluate for an association between risk factors and outcomes.

RESULTS

A total of 349 kpro procedures were performed in 295 eyes of 268 patients. Fifty-seven cases of presumed infectious keratitis were identified after 53 procedures (15.2%) in 50 eyes (16.9%) of 49 patients (18.3%). The incidences of culture-positive bacterial and fungal keratitis were 0.014 and 0.004 per eye-year, respectively. Persistent corneal epithelial defect formation (P < 0.001) and cicatricial disease (HR: 1.98, 95% confidence interval, 1.02-3.83) were associated with a significantly higher incidence of infectious keratitis. For the 53 cases with a known outcome, medical therapy achieved resolution of infection in 34 cases (64.2%), whereas kpro explantation was required in 19 cases (35.8%). Infectious keratitis was associated with an increased risk for kpro explantation (HR: 3.09, 95% confidence interval, 1.92-4.79).

CONCLUSIONS

Infectious keratitis develops in approximately 17% of eyes after kpro implantation, with a higher rate of culture-positive bacterial than fungal keratitis. The observed rate of microbial keratitis suggests the need for additional topical antimicrobial prophylaxis in eyes at higher risk, such as those with preexisting cicatricial disease or postoperative persistent corneal epithelial defect formation.

The Search for Antifungal Prophylaxis After Artificial Corneal Surgery-An In Vitro Study

PURPOSE

To evaluate the antifungal properties of topical antibiotics (already being used successfully to prevent bacterial endophthalmitis) and some promising antiseptics for antifungal prophylaxis in the setting of artificial corneal implantation.

METHODS

Several commonly used antibiotics for antimicrobial prophylaxis after artificial corneal implantation, in addition to antiseptics [benzalkonium chloride (BAK), povidone-iodine (PI), and some ionic liquids (ILs)], were tested in vitro against Candida albicans, Fusarium solani, and Aspergillus fumigatus. The time-kill activity was determined. Toxicity was assayed in vitro on human corneal epithelial cultures using trypan blue. Adhesion and tissue invasion experiments were also carried out on porcine corneas and commonly used contact lenses, with or without gamma irradiation, and by analysis with fluorescence microscopy.

RESULTS

Polymyxin B (PMB)/trimethoprim/BAK (Polytrim), PMB alone, gatifloxacin with BAK (Zymaxid), and same-concentration BAK alone exhibited antifungal activity in vitro. Moxifloxacin (MOX) or gatifloxacin without BAK-as well as trimethoprim, vancomycin, and chloramphenicol-had no effect. 1% PI and ILs had the highest efficacy/toxicity ratios (>1), and Polytrim was species dependent. Subfungicidal concentrations of Polytrim reduced adhesion of C. albicans to Kontur contact lenses. Gamma-irradiated corneas showed enhanced resistance to fungal invasion.

CONCLUSIONS

Of antibiotic preparations already in use for bacterial prophylaxis after KPro surgery, Polytrim is a commonly used antibiotic with antifungal effects mediated by both PMB and BAK and may be sufficient for prophylaxis. PI as a 1% solution seems to be promising as a long-term antifungal agent. Choline-undecanoate IL is effective and virtually nontoxic and warrants further development.

Application of Dimethyl Sulfoxide as a Therapeutic Agent and Drug Vehicle for Eye Diseases

Dimethyl sulfoxide (DMSO) is an amphipathic molecule widely used as a solvent for water-insoluble substances, cryopreserving, and cell-biological therapies. It has known properties as an inducer of cellular differentiation, a free radical scavenger, and a radioprotectant. In addition, DMSO is used for its various therapeutic and pharmaceutical properties, such as anti-inflammatory, local and systemic analgesic, antibacterial, antifungal, antiviral, and membrane penetration enhancement agents. DMSO treatment can be given orally, intravenously, or topically for a wide range of indications. The administration of DMSO exhibits favorable outcomes in human eye diseases with low to none observed ocular or systemic ocular toxicity. Nevertheless, DMSO is an essential and nonpatentable potential therapeutic agent that remains underexplored and ignored by pharmaceutical developers and ophthalmologists. This current review takes data from experimental and clinical studies that have been published to substantiate the potential therapeutic efficacy of DMSO and stimulate the research of its application in clinical ophthalmology. Given that DMSO is inexpensive, safe, and easily formulated into therapeutic medicinal products and conventional ophthalmological drugs, this compound should be further explored and studied in the treatment of a variety of acute and chronic ocular disorders.

Inflammation in Dry Eye Syndrome: Identification and Targeting of Oxylipin-Mediated Mechanisms

Dry eye syndrome (DES) is characterized by decreased tear production and stability, leading to desiccating stress, inflammation and corneal damage. DES treatment may involve targeting the contributing inflammatory pathways mediated by polyunsaturated fatty acids and their derivatives, oxylipins. Here, using an animal model of general anesthesia-induced DES, we addressed these pathways by characterizing inflammatory changes in tear lipidome, in correlation with pathophysiological and biochemical signs of the disease. The decline in tear production was associated with the infiltration of inflammatory cells in the corneal stroma, which manifested one to three days after anesthesia, accompanied by changes in tear antioxidants and cytokines, resulting in persistent damage to the corneal epithelium. The inflammatory response manifested in the tear fluid as a short-term increase in linoleic and alpha-linolenic acid-derived oxylipins, followed by elevation in arachidonic acid and its derivatives, leukotriene B4 (5-lipoxigenase product), 12-hydroxyeicosatetraenoic acid (12-lipoxigeanse product) and prostaglandins, D2, E2 and F2α (cyclooxygenase products) that was observed for up to 7 days. Given these data, DES was treated by a novel ophthalmic formulation containing a dimethyl sulfoxide-based solution of zileuton, an inhibitor of 5-lipoxigenase and arachidonic acid release. The therapy markedly improved the corneal state in DES by attenuating cytokine- and oxylipin-mediated inflammatory responses, without affecting tear production rates. Interestingly, the high efficacy of the proposed therapy resulted from the synergetic action of its components, namely, the general healing activity of dimethyl sulfoxide, suppressing prostaglandins and the more specific effect of zileuton, downregulating leukotriene B4 (inhibition of T-cell recruitment), as well as upregulating docosahexaenoic acid (activation of resolution pathways).

Comparison of the efficacy of tea tree (Melaleuca alternifolia) oil with other current pharmacological management in human demodicosis: A Systematic Review

Various treatments are found to be moderately effective in managing Demodex-related diseases except tea tree oil (TTO) and terpinen-4-ol (T4O), which showed superior miticidal and anti-inflammatory effects in numerous clinical studies. Their possible effects include lowering mite counts, relieving Demodex-related symptoms, and modulating the immune system. This review summarizes the current clinical topical and oral treatments in human demodicosis, their possible mechanisms of action, side-effects and resistance in treating this condition. TTO (especially T4O) is found to be the most effective followed by metronidazole, ivermectin and permethrin in managing the disease. This is because TTO has anti-parasitic, anti-bacterial, anti-fungal, anti-inflammatory and wound-healing effects. Furthermore, nanoTTO can even release its contents into fungus and Pseudomonas biofilms. Combinations of different treatments are occasionally needed for refractory cases, especially for individuals with underlying genetic predisposal or are immuno-compromised. Although the current treatments show efficacy in controlling the Demodex mite population and the related symptoms, further research needs to be focused on the efficacy and drug delivery technology in order to develop alternative treatments with better side-effects profiles, less toxicity, lower risk of resistance and are more cost-effective.

Management of meibomian gland dysfunction: a review

Meibomian gland dysfunction is the leading cause of evaporative dry eye disease and is one of the most common conditions encountered by eye care providers. The disorder is characterized by obstruction of the meibomian gland terminal ducts and/or changes in their glandular secretion, resulting in changes in tear film stability, inflammation, and symptoms of irritation. There is no gold standard treatment for meibomian gland dysfunction, but rather a diversity of options. Conservative measures include warm compresses and lid hygiene, but there is growing interest and need for medical treatments and procedures. Potential medical treatments include antibiotics, nonsteroidal and steroidal anti-inflammatory agents, essential fatty acid supplementation, hormone therapy, and control of Demodex infestation. Procedures include intraductal meibomian gland probing, the use of electronic heating devices, intense pulsed light therapy, and intranasal neurostimulation. We provide an update on meibomian gland dysfunction treatments based on recent studies.

Keratoprosthesis prophylaxis: is it time for a paradigm shift?

The Boston Type I Keratoprosthesis has been improving in both design and safety since its inception. Due to particular features inherent in the Boston Type I Keratoprosthesis eye and certain aspects of the ocular surface, special attention is required to maintain these implanted devices. There is currently a prominent role for keratoprosthesis prophylaxis; it is designed to prevent infectious complications like keratitis and endophthalmitis. This standard-of-care therapy has anecdotally been shown to improve outcomes; however, it has not been examined in the setting of controlled clinical trials. Moreover, concerns remain with the chronic utilization of topical antibiotics in that they may engender antibiotic resistance and select for opportunistic populations to establish a foothold on the ocular surface. We believe and introduce the idea that there is merit in exploring other compounds besides antibiotics for prophylaxis such as antiseptics like povidone-iodine. Specifically developed formulations of povidone-iodine may prove useful in both improving keratoprosthesis safety and simultaneously mitigating concerns regarding antibiotic resistance.

Resolution of iatrogenic calcinosis cutis in a dog through topical application of DMSO

A dog with calcinosis cutis was treated by topical dimethyl sulfoxide (DMSO) administration, reaching a complete involution of symptoms. DMSO is well-known for its transdermal penetration and anti-inflammatory capacity. For this reason, DMSO is proposed as a topical treatment for the management of calcinosis cutis in dogs. The authors present the clinical case of a dog with seropositive leishmaniosis and secondary immune-mediated haemolytic anaemia who was affected by intense dermatopathia on the dorsal area, diagnosed by a biopsy as calcinosis cutis. Injuries were described as necrotising ulcerative dermatitis. Currently, there are no specific treatments for its cure. The topical application of DMSO every other day was used as a unique treatment, and the use of other treatments like antibiotics or anti-inflammatory therapy was not necessary. Treating calcinosis cutis via a topical wash with DMSO every other day was effective for the symptoms of calcinosis cutis.