Diffusion of Antimicrobials Across Silicone Hydrogel Contact Lenses

Elucidating acceptance and clinical indications to support the rational design of drug-eluting contact lenses

The advent of drug-eluting contact lenses (DECLs) has opened up new avenues for the treatment of eye diseases. DECLs is expected to partially overcome the shortcomings of eye drops due to single-dose packaging, accurate dosing, prolonged drug elution behavior, and simplified dosing procedures. Currently, a significant proportion of the DECLs design effort has been directed towards enhancing the compatibility of contact lenses with drugs. The appropriate elution time for the drug remains unclear. Additionally, it is ambiguous for which ophthalmic diseases DECLs offers the greatest therapeutic advantage. To rationally design DECLs in practice, it is necessary to understand the acceptance of DECLs by patients and practitioners and to clarify the indications for DECLs. This review will first focus on the acceptance of DECLs by different patients and practitioners and discuss the factors that influence its acceptance. Secondly, this review presents an overview of the current effectiveness of DECLs treatments in animals and in the clinical phase, with a particular focus on the suitability of DECLs for the treatment of ophthalmic diseases. Overall, patients and practitioners expressed positive attitudes towards DECLs. However, this is related to factors such as DECLs' treatment cycle, safety, and price. In addition, DECLs has good application prospects for ocular wound healing, postoperative management, and treatment of contact lenses-related complications. Furthermore, chronic diseases such as glaucoma that necessitate long-term medication and intraocular diseases that require implants or injections represent additional potential applications for DECLs. It is hoped that this review will facilitate a deeper understanding of DECLs acceptance and indications, thereby supporting the rational design of DECLs. At the same time, this review provides a reference for the design of other drug-device combination products.

Indications and Results of Emergency Penetrating Keratoplasty With Simultaneous Cataract Surgery ("Triple-PKP à Chaud")

PURPOSE

The purpose of this study was to analyze the indications and clinical results of emergency penetrating keratoplasty with simultaneous cataract surgery ("Triple-PKP à chaud").

METHODS

This study included all subjects who underwent Triple-PKP à chaud between 2006 and 2020 at the Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar in Germany. Data obtained from patient records were retrospectively analyzed.

RESULTS

Triple-PKP à chaud was successfully performed in 27 of 29 eyes with a mean age of 66.0 ± 19.9 years. Previous surgery was performed in 20 eyes (69.0%), most frequently amniotic membrane transplantation in 11 eyes (37.9%) and previous keratoplasty in 9 eyes (31.0%). The most common indication was infectious keratitis (62.1%). In 27 subjects (93.1%), capsulorhexis was performed using the open-sky technique. The most frequent intraoperative complication was positive vitreous pressure (24.1%). In 2 eyes (6.9%), no intraocular lens implantation was performed because of posterior capsule rupture. The preoperative uncorrected visual acuity improved from 2.2 ± 0.6 logMAR (range = 3.0-0.7 logMAR) to 1.3 ± 0.7 logMAR (range = 3.0-0.18 logMAR) postoperatively ( P < 0.001). Common postoperative complications were suture loosening (44.4%) and corneal epithelial defects (33.3%). Repeat keratoplasty was necessary in 14 eyes (51.9%), including 9 eyes (64.2%) within 12 months postoperatively. The mean graft survival was 12.2 ± 17.9 months (range = 1-69 mo).

CONCLUSIONS

Triple-PKP is also feasible in emergency conditions. Nevertheless, the surgery is associated with an increased risk of intraoperative and postoperative complications. Combined surgery should, therefore, only be performed in severely diseased eyes with progressed stage of cataract.

Polyhexamethylene biguanide hydrochloride (PHMB)-properties and application of an antiseptic agent. A narrative review

The prevention and management of ocular surface infections is still one of the great challenges for ophthalmologists. The spread of antimicrobial resistance makes it necessary to use antiseptic substances with a broad antimicrobial spectrum. Polyhexamethylene biguanide hydrochloride (Polyhexanide, PHMB) is a broad-spectrum antiseptic with excellent tolerance and a low-risk profile. Its physicochemical action on the phospholipid membrane and DNA replication or repair mechanism, prevents or impedes the development of resistant bacterial strains. PHMB revealed its effective against numerous organisms like viruses, Gram-negative and Gram-positive bacteria, and fungi. Polyhexanide is commonly used as preservative in commercially available disinfecting solutions for contact lens care and in ophthalmic formulations at different concentrations ranging from 1 µg/ml to 50 µg/ml. The administration of 0.02% (200 µg/ml) PHMB is often the first-line therapy of Acanthamoeba keratitis. However, to date, only one close-out randomized controlled study tested the efficacy of 0.02% PHMB in Acanthamoeba keratitis and a phase III study is still ongoing. This paper reviews the antiseptic agent PHMB, focusing on biochemical mechanisms, safety profile and applications in ophthalmology.

Efficacy of bandage contact lens for the management of dry eye disease after cataract surgery

Purpose

We aimed to evaluate the efficacy of bandage contact lens (BCL) for the management of dry eye disease (DED) after cataract surgery.

Methods

A total of 120 patients (140 eyes) with age-related cataract and DED were enrolled in this study. Patients underwent standard micro-incision phacoemulsification surgeries and were divided into control or BCL groups. Slit-lamp biomicroscopic examination, Ocular Surface Disease Index, keratograph analysis and Schirmer I test were executed, and the levels of tear inflammatory molecules were detected.

Results

In the control group, the NIAvg-BUT and Schirmer I test scores were significantly decreased at 1 week post-operation compared with baseline levels (P = 0.035 and P = 0.009, respectively). In the BCL group, the NIF-BUT and Schemer I test scores were significantly improved at 1 month after operation compared with the control group (P = 0.012 and P < 0.001, respectively). Levels of IL-6, IL-8 and ICAM-1 were significantly increased in the control group at 1 month after the operation (P = 0.005, P = 0.038 and P = 0.022, respectively), while there was no difference in the BCL group. The increase in the IL-6 level in the control group was significantly higher compared with that in the BCL group (P = 0.047). In DED patients, there were significant correlations between ocular surface parameters and inflammatory molecules.

Conclusions

Cataract surgery could lead to the development or worsening of DED. The application of BCLs after cataract surgery could stabilize the ocular surface and tear film, improve the corneal healing and reduce the inflammation. Collectively, our findings suggested that proper use of BCLs after cataract surgery played an effective role in the management of DED.

Trial registration

ClinicalTrials, NCT04100031. Registered 18 September 2019—retrospectively registered

Release of Moxifloxacin From Corneal Collagen Shields

OBJECTIVES

To investigate the diffusion of moxifloxacin through bandage contact lenses (BCLs) versus corneal collagen shields (CSs), the relative ability of BCLs and CSs to release moxifloxacin, and the potential of release of moxifloxacin from CSs in the clinical setting.

METHODS

Using an in vitro model, the diffusion of 5% moxifloxacin across BCLs and CSs was compared. Next, the amount of drug release from BCLs and CSs soaked in 0.5% moxifloxacin was measured. Finally, based on a clinical model, CSs were soaked in Vigamox (commercial moxifloxacin) and the total concentration released was detected. Collagen shields remained intact after 24 hr; therefore, enzymatic digestion and mechanical grinding of the CS were performed to determine whether further drug could be released. The concentration of moxifloxacin was measured using a spectrophotometer at set time points up to 24 hr.

RESULTS

In the diffusion assay, 35.7±10.5% diffused through the BCLs and 36.2±11.8% diffused through the CSs (P=0.77). The absorption assay demonstrated at 120 min, a total of 33.3±6.77 μg/mL was released from BCLs compared with 45.8±5.2 μg/mL from the CSs (P=0.0008). In vitro experiments to simulate clinical application of Vigamox-soaked CS found the concentration of moxifloxacin released of 127.7±7.25 μg/mL in 2 mL of phosphate-buffered saline over 24 hr.

CONCLUSIONS

Moxifloxacin diffuses through BCLs and CSs at similar rates; however, CSs have greater capacity to absorb and release moxifloxacin compared with BCLs. Vigamox-soaked CSs released 250 μg of moxifloxacin and may be a useful method to prevent endophthalmitis.