Effectiveness and Safety of Topical Chlorhexidine and Vitamin E TPGS in the Treatment of Acanthamoeba Keratitis: A Survey on 29 Cases

Acanthamoeba Keratitis Management and Prognostic Factors: A Systematic Review

Background/Objectives: The aim of this study was to review the therapeutic and prognostic factors influencing Acanthamoeba Keratitis (AK) management. Methods: A systematic search was performed across MEDLINE® (via PubMed), Web of Science®, and Scopus®, following the PRISMA 2020 guidelines, and registered in PROSPERO (CRD420251010774). Studies reporting AK treatment regiments and prognostic factors were included. After extracting the data from the included articles, the relevant aspects of the treatment and the prognostic factors were compared and summarized. Results: Sixty-one articles were included: nine were prospective, including 3 randomized controlled trials (RCTs), and fifty-two were retrospective. The findings suggest that therapeutic epithelial debridement (TED), followed by an association with biguanides, diamidines, and an antibacterial agent, is a strong initial treatment option. An adjunctive medical treatment with topical voriconazole 1% or oral miltefosine may also be considered. Surgical approaches were also assessed when the pharmaceutical therapy failed, with Deep Anterior Lamellar Keratoplasty (DALK) playing an important role in the cases without a deep stroma involvement. Early Therapeutic Penetrating Keratoplasty (TPK) should be used as a salvage therapy and Optical Penetrating Keratoplasty (OPK) should be used for rehabilitation purposes. Key prognostic factors include older age, delayed diagnosis, corticosteroid use before prompt diagnosis, poor initial best corrected visual acuity (BCVA), and AK stage at presentation. Conclusions: The initial treatment with TED, biguanides, and diamidines remains the foundation of treatment. Surgical options can be considered in advanced cases. An early diagnosis, age, and initial BCVA are prognosis factors that should be considered. Future research may focus on improvement of protocols and searching for novel agents.

Efficacy and Safety of Keratosept Eye Drops in Patients with Punctate Keratitis: Clinical and Microbiological Evaluation on 50 Eyes

We evaluated the efficacy and safety of eye drops with antiseptic and re-epithelizing properties (Keratosept®, Bruschettini, Genova, Italy) on 50 eyes affected by punctate keratitis of suspected microbial origin. A biomicroscopic examination, fluorescein dye staining test (Fluotest), tear break-up time test (TBUT), and the ocular surface disease Index (OSDI) questionnaire were used to assess treatment efficacy. Treatment success was defined as a negative Fluotest and an OSDI score <12 on the 15th day of treatment. According to this definition, Keratosept®, either alone or in combination with antibiotics, was effective in over 80% of microbial and nonmicrobial forms. Conjunctival swabs were taken from all patients for culture examination with an antibiogram and sensitivity test for Keratosept®; 32/43 (74.4%) forms with positive culture for the bacteria were sensitive to Keratosept®. A total of 35/38 (92%) eyes treated with this product alone achieved full treatment success without any apparent adverse effects. These results suggest the use of Keratosept® eye drops in punctate keratitis as an alternative or in combination with established antibiotic therapies. Further studies are needed to evaluate its efficacy in different infectious forms and identify other indications for using this product.

Development of ophthalmic nanoemulsions of β-caryophyllene for the treatment of Acanthamoeba keratitis

Although rare, amoebic keratitis (AK) is a disease caused by Acanthamoeba spp. that can lead to blindness. The drugs currently available for its treatment are very toxic, which has motivated the investigation for more effective and safe therapeutic options. In this study, the in vitro activity of ß-caryophyllene (BCP) was exploited taking into account its action against other protozoans as well as its well-known healing and anti-inflammatory properties (aspects relevant for the AK pathogenesis). On the other hand, high volatilization and oxidation phenomena are found for this compound, which led to its incorporation into nanoemulsions (NEs). Two emulsifying agents were tested, resulting in monodisperse systems with reduced droplet size (<265 nm) and high surface charge (positive and negative for NEs prepared with cetrimonium bromide -CTAB and Phosal® 50+, respectively). NEs prepared with CTAB were shown to be more stable after long-term storage at 4 and 25 °C than those prepared with Phosal®. Pure BCP, at the highest concentration (500 µM), resulted in a level of inhibition of Acanthamoeba trophozoites equivalent to that of reference drug (chlorhexidine). This activity was even greater after oil nanoencapsulation. The reduced droplet size could improve the interaction of the oil with the microorganism, justifying this finding. Changes in surface charge did not impact the activity. Positively charged NEs improved the interaction and retention of BCP in the cornea and thus should be prioritized for further studies.

New Frontiers in Acanthamoeba Keratitis Diagnosis and Management

Acanthamoeba Keratitis (AK) is a severe corneal infection caused by the Acanthamoeba species of protozoa, potentially leading to permanent vision loss. AK requires prompt diagnosis and treatment to mitigate vision impairment. Diagnosing AK is challenging due to overlapping symptoms with other corneal infections, and treatment is made complicated by the organism's dual forms and increasing virulence, and delayed diagnosis. In this review, new approaches in AK diagnostics and treatment within the last 5 years are discussed. The English-language literature on PubMed was reviewed using the search terms "Acanthamoeba keratitis" and "diagnosis" or "treatment" and focused on studies published between 2018 and 2023. Two hundred sixty-five publications were initially identified, of which eighty-seven met inclusion and exclusion criteria. This review highlights the findings of these studies. Notably, advances in PCR-based diagnostics may be clinically implemented in the near future, while antibody-based and machine-learning approaches hold promise for the future. Single-drug topical therapy (0.08% PHMB) may improve drug access and efficacy, while oral medication (i.e., miltefosine) may offer a treatment option for patients with recalcitrant disease.

Comparative Evaluation of Antimicrobial, Antiamoebic, and Antiviral Efficacy of Ophthalmic Formulations

The extensive use of ophthalmic antibiotics is contributing to the appearance of resistant bacterial strains, which require prolonged and massive treatments with consequent detrimental outcomes and adverse effects. In addition to these issues, antibiotics are not effective against parasites and viruses. In this context, antiseptics could be valuable alternatives. They have nonselective mechanisms of action preventing bacterial resistance and a broad spectrum of action and are also effective against parasites and viruses. Here, we compare the in vitro antibacterial, antiameobic, and antiviral activities of six ophthalmic formulations containing antiseptics such as povidone-iodine, chlorhexidine, and thymol against Gram-positive and Gram-negative bacteria, the amoeba Acanthamoeba castellanii, and two respiratory viruses, HAdV-2 and HCoV-OC43. The results suggest that, among all the tested formulations, Dropsept, consisting of Vitamin E TPGS-based (tocopheryl polyethylene glycol succinate) in combination with the antiseptic chlorhexidine, is the one with the highest range of activities, as it works efficiently against bacteria, amoeba, and viruses. On the other hand, the solution containing PVA (polyvinyl alcohol) and thymol showed a promising inhibitory effect on Pseudomonas aeruginosa, which causes severe keratitis. Given its high efficiency, Dropsept might represent a valuable alternative to the widely used antibiotics for the treatment of ocular infections. In addition to this commercial eye drop solution, thymol-based solutions might be enrolled for their natural antimicrobial and antiamoebic effect.

Inhibitory Effect of Ophthalmic Solutions against SARS-CoV-2: A Preventive Action to Block the Viral Transmission?

In 2020, a global pandemic was declared following the spread of SARS-CoV-2, the pathogen responsible for COVID-19. The risk of infection is high due to the ease of transmission, which can occur orally, through droplets, or via contact with contaminated surfaces and objects. It has also been demonstrated that the ocular surface can constitute a transmission route, especially in hospital settings, where health care workers can become a dangerous source of infection. In order to increase prevention and reduce the spread of the virus on the ocular surface, the antiviral activity of already-marketed eye drops against SARS-CoV-2 was evaluated. Iodim, Ozodrop, Septavis, and Dropsept were tested against SARS-CoV-2 in plaque-assay experiments at different stimulation times. Furthermore, the expression levels of early and late genes were evaluated through molecular assays. Results indicated that three of the four ophthalmic solutions showed a considerable dose-dependent inhibition of viral replication, highlighting their use as potential antiviral drugs against SARS-CoV-2 and preventing other ocular infections.