Evaluation of corneal damage caused by iodine preparations using human corneal epithelial cells

Transcorneal aspiration for management of primary iris cysts in the standing horse

BACKGROUND

Equine primary iris cysts are usually incidental findings but, if associated with clinical signs, may require intervention. The use of laser (Nd:Yag or diode) has been reported but requires specialised equipment. Transcorneal aspiration has not been previously evaluated in the standing horse.

OBJECTIVES

To review outcomes of standing transcorneal aspiration of primary iris cysts (STAPIC) in horses.

METHODS

Horses were identified from electronic patient records from 2018 to 2024 across four collaborating centres. Clinical presentation and outcomes were identified and reported using descriptive statistics.

RESULTS

Eighteen horses were identified. Behavioural signs reported included 'spooking' and changes in rideability often associated with jumping. Single large unilateral cysts were present in 11 horses, bilateral cysts in three horses and multiple unilateral cysts in four horses. Following treatment, one horse developed uveitis and fibrin in the anterior chamber associated with needle contact with the iris stroma due to movement, and a second horse developed fibrin within the anterior chamber. Both conditions resolved with anti-inflammatory medication and administration of tissue plasminogen activator. No other adverse effects were reported. Follow-up was available from all horses (median: 6 months, interquartile range [IQR]: 4-11 months) with no recurrence, although one horse developed an iris cyst in the contralateral eye after 3 years. All owners reported improvement in clinical signs, with 61% reporting no further signs.

CONCLUSIONS

STAPIC is an effective and easily accessible alternative for treating iris cysts in horses rarely associated with complications.

Efficacy and Safety of Preoperative Prophylaxis in Cataract Surgery with Combined Topical Antiseptics: A Microbiological Study

INTRODUCTION

To evaluate the antimicrobial efficacy of an ophthalmic formulation containing hexamidine diisethionate (HD) 0.05%, polyhexamethylene biguanide (PHMB) 0.0001%, and edetate disodium (EDTA) 0.01% (Keratosept®, Bruschettini, Genova, Italy) on the microbial flora of a healthy ocular surface.

METHODS

Patients were enrolled consecutively. Each patient applied two drops of Keratosept® in the eye scheduled for cataract surgery (study eye) three times daily in the 2 days prior to surgery and one time in the morning of surgery. The contralateral eyes were considered as control (control eye). Bilateral conjunctival swabs were collected before the first administration (T0) and the morning of surgery (T1). The swabs were processed within 3 h from sampling for the automated detection of the presence of replicating microorganisms (colony-forming units, CFU/mL) and the provision of real-time growth curves.

RESULTS

Conjunctival swabs of 32 patients (n = 128) were examined. Six patients were excluded from the efficacy analysis because of microbial load < 50 CFU/mL at T0 in the study eye. No difference between study and control eyes was observed at T0 (p = 0.40). Compared with T0, 20 (76.9%) study eyes and 10 (38.5%) control eyes showed a ≥ 1 log reduction of the microbial load at T1, with a significant difference between groups (p = 0.005). Keratosept® showed good tolerability, and no adverse events or eye discomfort were recorded.

CONCLUSIONS

This study showed that the low-dose combination of antiseptic agents in the Keratosept® ophthalmic solution effectively reduces the bacterial load of healthy flora on the ocular surface.

Povidone-iodine in vitro antiseptic efficacy as a function of exposure duration, concentration, preparation, and length of storage

PURPOSE

Although 5% povidone-iodine (PVP-I) is frequently used as an ocular antiseptic agent, there is a lack of consensus regarding the effects of PVP-I concentration, storage after opening, and compounded preparation on PVP-I antisepsis. We performed a series of in-vitro experiments to determine the impact of these factors on PVP-I's inhibition of common causes of post-procedural eye infection.

METHODS

Inhibition of microorganism growth was measured in-vitro as a function of active PVP-I exposure time. In control experiments, PVP-I was inactivated before microorganism exposure. Tested PVP-I solutions varied in concentration (0.6%, 5%, or 10%), length of storage after opening (0, 7, or 30 days), and preparation (commercial vs.compounded from stock PI solution). Tested pathogens included S. epidermidis, S. viridans, P. aeruginosa, methicillin-resistant S. aureus, methicillin-sensitive S. aureus, and C. albicans.

RESULTS

PVP-I solutions inhibited all bacterial growth by 3 min and fungal growth by 15 s. Compared to 5% PVP-I, the 0.6% PVP-I was less effective in inhibiting S. viridans growth (200 ± 0 colonies vs. 7 ± 8 at 30 s, P = 0.0004; 183 ± 21 vs. 0 ± 0 at 1 min, P = 0.018), but more effective in inhibiting P. aeruginosa (30 ± 20 vs. 200 ± 0 at 15 s, P = 0.019). Compared to commercial and newly-opened PVP-I solutions, compounded preparations and solutions stored for 7 or 30 days after bottle opening either preserved or improved antiseptic efficacy against tested microorganisms.

CONCLUSIONS

Concentration of PVP-I solution affects antiseptic efficacy within 1 min of exposure, but all solutions performed equivalently at 3 min. In contrast to results of prior studies investigating dilute PVP-I, the 0.6% PVP-I did not demonstrate a uniformly equivalent or superior anti-septic effect. Compounded preparation and storage length after bottle opening did not decrease PVP-I antiseptic activity.

In vivo assessment of antimicrobial activity and toxicity of repeated 1% povidone-iodine applications vs a single 5% povidone-iodine application

PURPOSE

To demonstrate the noninferiority in antimicrobial effectiveness of thrice-repeated applications of 1% povidone-iodine (PI) compared with a single application of 5% PI on the ocular surface in vivo and to evaluate potential toxicity of PI to the corneal epithelium.

SETTING

Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel.

DESIGN

Prospective, randomized, double-blind study.

METHODS

Patients randomly received either a single application of 5% PI or repeated irrigations of 1% PI on the ocular surface preoperatively. Bacterial colony counts were quantitatively analyzed by taking standardized conjunctival swabs before and after irrigation, and differences in bacterial colony counts were compared between the 2 groups. The presence of superficial punctate keratopathy was evaluated in all patients by the National Eye Institute grading system.

RESULTS

The study comprised 102 eyes of 102 patients. Both 1% and 5% PI yielded a marked decrease in bacterial colonies compared with before application ( P < .001). The repeated application of 1% PI showed a significantly lower bacterial count compared with the single application of 5% PI ( P < .05) and resulted in significantly less damage to the corneal epithelium compared with a single 5% PI application ( P < .001).

CONCLUSIONS

Preoperative repeated applications of 1% PI effectively eradicated ocular surface bacteria equal to that of 5% PI with a less deleterious effect on the corneal epithelium. Our findings suggest that 1% PI may be a promising alternative to 5% PI.

Quality assurance in corneal transplants: Donor cornea assessment and oversight

The cornea is the most frequently transplanted human tissue, and corneal transplantation represents the most successful allogeneic transplant worldwide. In order to obtain good surgical outcome and visual rehabilitation and to ensure the safety of the recipient, accurate screening of donors and donor tissues is necessary throughout the process. This mitigates the risks of transmission to the recipient, including infectious diseases and environmental contaminants, and ensures high optical and functional quality of the tissues. The process can be divided into 3 stages: (1) donor evaluation and selection before tissue harvest performed by the retrieval team, (2) tissue analysis during the storage phase conducted by the eye bank technicians after the retrieval, and, (3) tissue quality checks undertaken by the surgeons in the operating room before transplantation. Although process improvements over the years have greatly enhanced safety, quality, and outcome of the corneal transplants, a lack of standardization between centers during certain phases of the process still remains, and may impact on the quality and number of transplanted corneas. Here we detail the donor screening process for the retrieval teams, eye bank operators. and ophthalmic surgeons and examine the limitations associated with each of these stages.

The Inflammatory and Cytological Effect of Repeated Povidone-Iodine Application in Patients Receiving Intravitreal Injections

OBJECTIVE

To investigate the effect of repeated povidone-iodine (PVI) application on the ocular surface parameters of patients who received intravitreal injections.

MATERIALS AND METHODS

In this prospective study, 52 eyes of 52 patients with age-related macular degeneration who underwent unilateral intravitreal injection at least three times in the last 1 year (intravitreal injection [IVI] group), 52 fellow eyes with no previous intravitreal injection (NIVI group), and 51 eyes of 51 healthy subjects (control) were included. Tear break-up time (TBUT), the Schirmer test, the Oxford staining score, the Ocular Surface Disease Index questionnaire, conjunctival impression cytology, and tear inflammatory cytokine levels (interleukin [IL]-1β and IL-6) were analyzed in all participants.

RESULTS

The IVI group had lower TBUT and higher Oxford staining score than the NIVI and control groups ( P <0.05). No significant difference was found between the groups in the Schirmer test ( P =0.161). Conjunctival impression cytology analysis revealed that the IVI group had a significantly lower goblet cell count and significantly higher Nelson staging result than the NIVI and control groups ( P <0.05). As a result of tear cytokine analysis, although IVI and NIVI groups had higher IL-1β and IL-6 levels than the control group ( P <0.05), there was no difference between NIVI and IVI groups ( P ≥0.05).

CONCLUSIONS

Repeated PVI application caused cytotoxic injury to the ocular surface, resulting in goblet cell loss and squamous metaplasia of epithelial cells. As a result, the stability of the tear film layer was found to be impaired and ocular surface-related symptoms developed in patients.

Evaluation of the Possible Influence of Povidone Iodine (PVI) Solution and Polyhexanide (PHMB) on Wound Healing in Corneal Epithelial Regeneration

This study investigates the possible toxic effects of the preoperative antiseptic substances povidone iodine (PVI) and polyhexanide (PHMB; Serasept® 2) on wound healing in ophthalmology. To assess this impact, human telomerase-immortalized corneal epithelial (hTCEpi) cells and human telomerase-immortalized conjunctival epithelial (hCjE) cells were exposed to 1% and 5% PVI or 0.04% PHMB for different periods to evaluate the cytotoxicity of these two antiseptics. Furthermore, the toxicity of these antiseptics was investigated in a human tissue-specific corneal epithelial construct and porcine eye culture model. The results reveal the high cytotoxicity of PVI and PHMB in the hTCEpi and hCjE in monolayer cell culture models, independent of the incubation time and concentration of these substances. However, after hTCEpi cell differentiation into a tissue-specific corneal epithelial construct, contact with these antiseptics for the relevant preoperative time did not alter cPARP1 or Ki67 expression. Furthermore, the wound-healing process in the porcine cornea was not significantly influenced after incubation with these antiseptics. In summary, corneal and conjunctival epithelial cell lines are very sensitive to PVI and PHMB, whereas no significant alterations were found in intact tissue-specific corneal epithelial constructs or porcine corneas. Therefore, we could not identify PVI and PHMB as reasons for postoperative eye irritation.

Evaluation of anti-adenoviral effects of the polyvinyl alcohol iodine ophthalmic solution

PURPOSE

To investigate the virucidal effects of a polyvinyl alcohol iodine, Saniode, against 16 types of human mastadenovirus (HAdV) causing ophthalmic, respiratory, gastrointestinal, urinary, and systemic infections.

STUDY DESIGN

Laboratory investigation METHODS: Fifty microliters of Saniode were exposed to 10 μL each containing HAdV virus stock solution of 1 × 106 copies/μL of HAdV-1, -2, -3, -4, 5, -6, -7, -8, -11, -37, -53, -54, -56, -64, -81, and -85 for 10 s, 30 s, 1 min, and 3 min. After neutralization with 0.5% sodium thiosulfate, the mixture was diluted by ten-fold serial dilution and inoculated into 24 wells containing confluent A549 cell monolayers. Virucidal effects were calculated relative to the positive control on days 7-10 and observed until 30 days post-infection.

RESULTS

Saniode satisfied the EN-14476 criterion for virucidal effects (>99.99%) for all HAdV types at all exposure times, including at 10 s on days 7 to 10 post-infection. All types of HAdVs that reacted for > 1 min achieved 99.99% reduction, including after 30 days.

CONCLUSION

Saniode displayed virucidal effects against all tested HAdV types. Currently, with no specific medication available for HAdVs in ocular infection, this could be an option to prevent the spread of keratoconjunctivitis.

Oxidative stress in the eye and its role in the pathophysiology of ocular diseases

Oxidative stress occurs through an imbalance between the generation of reactive oxygen species (ROS) and the antioxidant defense mechanisms of cells. The eye is particularly exposed to oxidative stress because of its permanent exposure to light and due to several structures having high metabolic activities. The anterior part of the eye is highly exposed to ultraviolet (UV) radiation and possesses a complex antioxidant defense system to protect the retina from UV radiation. The posterior part of the eye exhibits high metabolic rates and oxygen consumption leading subsequently to a high production rate of ROS. Furthermore, inflammation, aging, genetic factors, and environmental pollution, are all elements promoting ROS generation and impairing antioxidant defense mechanisms and thereby representing risk factors leading to oxidative stress. An abnormal redox status was shown to be involved in the pathophysiology of various ocular diseases in the anterior and posterior segment of the eye. In this review, we aim to summarize the mechanisms of oxidative stress in ocular diseases to provide an updated understanding on the pathogenesis of common diseases affecting the ocular surface, the lens, the retina, and the optic nerve. Moreover, we discuss potential therapeutic approaches aimed at reducing oxidative stress in this context.

Antiseptics and the Ocular Surface: In Vitro Antimicrobial Activity and Effects on Conjunctival and Corneal Epithelial Cells of a New Liposomal Ocular Spray Containing Biosecur® Citrus Extract

Introduction

Methods

Results

Conclusion

The effect of punctal plugs in reducing ocular surface irritation after povidone-iodine preparation of intravitreal injection-a randomized trial

PURPOSE

To evaluate the utility of dissolvable collagen punctal plugs (CPP) in reducing ocular surface irritation after intravitreal injections (IVI).

METHODS

Sixty-four subjects in the experimental group received CPP after intravitreal injections. Sixty-two controls did not receive CPP. Reductions in the Ocular Surface Disease Index© (OSDI) and Standardized Patient Evaluation of Eye Dryness II (SPEED II) scores were analysed.

RESULTS

Dry eye symptoms, as measured by reductions from the pre- to post-injection OSDI (p = 0.137) and SPEED II (p = 0.381) scores, did not significantly differ between the two groups. In sub-group analysis, patients with objective findings of dry eyes had significant improvement in their symptoms (p = 0.046) with CPP. The effect of CPP is not significant in those without dry eyes (p = 0.27).

CONCLUSION

CPPs were not effective in reducing post-injection ocular irritation in patients with no or only mild dry eye symptoms. CPPs improved patients' post-injection comfort levels in those who had moderate-to-severe symptoms and objective findings of dry eye. Though costly CPP could be considered in selective patients. A standardized eye rinse could be a simple, efficacious, and cost-effective way to reduce post-injection ocular irritation; however, more studies are needed.

The Effect of Past Cataract Surgery within the Medium to Long-Term Period on Patients with Dry Eye Disease

This study investigates the effects of cataract surgery on dry eye parameters of patients with dry eye disease (DED) in the medium- to long-term post-surgical period (6 months to 5 years). A cross-sectional study was conducted on 438 eyes on first visit to a tertiary clinic (219 eyes with cataract surgery within timeframe, i.e., pseudophakic dry eye group, 219 comparison eyes without such history, i.e., comparison dry eye group). Parameters evaluated include Ocular Surface Disease Index (OSDI) and standard examination for DED. A significantly greater proportion of pseudophakic dry eye group (50%) experienced frequent blurred vision (≥1 episode per week) compared to dry eye control group (38%) (OR = 1.66, 95%CI 1.13, 2.44). Those with ocular discomfort before surgery were more likely to experience blurring at least once a day. However, a significantly greater proportion of the pseudophakic dry eye group (34%) had Schirmer’s I >8mm compared to the comparison group (25%) (OR = 0.605, 95% CI 0.398, 0.921), though the difference was not clinically significant (7.51 mm versus 6.51 mm, p > 0.05). Other DED signs (e.g., overall OSDI score, Tear Break-up Time) were not found to be worse among pseudophakic dry eye group. Pre-operative counselling and preventative measures should be undertaken, especially those with suggestive symptoms pre-operatively.

[The in vitro effect of antiseptics on epithelial cells of human cornea and conjunctiva]

Effective and safe antiseptic eye preparations are necessary for prevention and treatment of infectious and inflammatory eye diseases.

PURPOSE

in vitro evaluation of the effect of antiseptic eye drops on corneal and conjunctival epithelial cells.

MATERIAL AND METHODS

Antiseptic eye drops «Bactavit», «Vitabact» and «Ocomistin» were the object of the study. Immortalized human corneal epithelial cell lines (HCE) and human conjunctiva (Chang Conjunctiva, Clone 1-5c-4) were used as the test systems. The viability of the cells was assessed by their metabolic activity and morphology using the MTT test and phase-contrast microscopy.

RESULTS

Antiseptic eye drops belonging to different groups of chemical compounds induced cytotoxic effects on the cells of corneal epithelium (HCE) and human conjunctiva (Chang Conjunctiva, Clone 1-5c-4) of varying degrees, leading to morphological and functional changes in those cells.

CONCLUSION

The study confirms the possibility of using cultured cells for the in vitro comparative assessment of the cytotoxic effect of antiseptic ophthalmic agents.

Review, analysis, and education of antiseptic related ocular injury in the surgical settings

Preoperative skin antiseptic preparation is the gold standard for prevention of surgical infection. However, improper use of antiseptics may lead to severe ocular damage. Currently, the most common surgical antiseptics can be divided into aqueous-based and alcohol-based disinfectants, with chlorhexidine and iodine/iodophors being the two major components. Chlorhexidine has a persistent antimicrobial effect and is resistant to neutralization by blood or organic products in surgical wounds. Nevertheless, due to its toxicity to the ears, meninges, and eyes, application of chlorhexidine should be prohibited in these surgical fields. Iodine/iodophor is better tolerated by the ocular surface and is the recommended antiseptic for ophthalmic or head and neck surgeries close to the periocular area. Alcohol is less pricey and has a rapid antiseptic effect, though its desiccating effect and flammability restrict the use in mucosal or laser surgeries. The single or combined use of these antiseptics may inadvertently induce severe ocular damage, especially during time-consuming head and neck surgeries with prone, hyperextension, or lateral tilt positions, or surgeries under general anesthesia. Apart from the choice of antiseptics, appropriate selection and attachment of bio-occlusive dressings are key to avoiding antiseptic-related ocular injuries. In this review, we provided a comprehensive summary of the characteristics of antiseptics used in surgical settings and the possible mechanisms and outcomes of antiseptic-related ocular injuries. The prevention, diagnosis, and acute management of these complications were also discussed.

Ocular Distribution of Papaverine Using Non-aqueous Vehicles

Papaverine, a poorly soluble opium alkaloid, has recently been shown to reduce retinal inflammation due to which it may have therapeutic application in the management of Leber's hereditary optic neuropathy. In this study, papaverine eyedrops based on medium chain triglycerides were prepared and the effect of diethyl glycol monoethyl ether (DGME) on their ocular distribution was evaluated using an ex vivo porcine eye model. The route of drug penetration was also studied by orienting the eye to expose either only the cornea or the sclera to the formulation. Furthermore, in vivo studies were performed to confirm ocular tolerability and evaluate ocular drug distribution. Our results showed increased papaverine concentrations in the cornea and sclera in the presence of DGME but with a slight reduction in the retina-choroid (RC) drug concentration when administered via the corneal route, suggesting that DGME enhances drug accumulation in the anterior ocular tissues but with little effect on posterior drug delivery. In vivo, the papaverine eyedrop with DGME showed good ocular tolerability with the highest drug concentration being observed in the cornea (1.53 ± 0.28 μg/g of tissue), followed by the conjunctiva (0.74 ± 0.18 μg/g) and sclera (0.25 ± 0.06 μg/g), respectively. However, no drug was detected in the RC, vitreous humor or plasma. Overall, this study highlighted that DGME influences ocular distribution and accumulation of papaverine. Moreover, results suggest that for hydrophobic drugs dissolved in hydrophobic non-aqueous vehicles, transcorneal penetration via the transuveal pathway may be the predominant route for drug penetration to posterior ocular tissues. Graphical abstract.

[Establishing Evidence for Use of Appropriate Medicines in the Operating Room]

Various issues related to clinical use of medicines remain unclear, and pharmacists are expected to establish evidence for appropriate use of medicines. The present review summarizes our findings from three areas of research regarding the use of medicines in the operating room: 1) We evaluated the extent of extravasation injury due to thiopental (2.5 mg/100 μL) and propofol (1.0 mg/100 μL) at the macroscopic and histopathologic levels in a rat model. Thiopental, which causes tissue necrosis, can be classified as a "vesicant", and propofol can be classified as an "irritant". Moreover, warming strongly exacerbated the degeneration or necrosis induced by extravasation of thiopental. 2) The cytotoxicity of povidone-iodine solution (PVP-I) for ophthalmic use and that of polyvinyl alcohol-iodine solution (PAI) was compared using a human corneal epithelial cell line. Despite exhibiting equivalent antiseptic effects, the cytotoxicity of PVP-I diluted 16-fold was greater than that of PAI diluted 6-fold. After inactivation of iodine, the cytotoxicity of PVP-I persisted; therefore, to avoid corneal damage, antisepsis should be achieved with PAI. 3) The stability of 1 μg/mL adrenaline when used as an intraocular irrigating solution to maintain pupil dilation was evaluated. After mixing for 6 h, the adrenaline concentration was 65.2% (pH 8.0) of the initial concentration. Moreover, the low concentration of sodium bisulfite in the irrigating solution could have caused adrenaline reduction. Our results strongly suggest that intraocular irrigation solution containing adrenaline should be prepared just prior to use in surgery.

Comparative study of topical regimen for adenoviral kearoconjunctivitis by 0.1% fluorometholone with and without polyvinyl alcohol iodine

PURPOSE

The aim of this study was to compare the efficacy of the topical regimens of iodine/steroids vs. antibiotics/steroids in acute to subacute adenoviral keratoconjunctivitis.

STUDY DESIGN

A prospective open-label study.

PATIENTS AND METHODS

Nineteen patients diagnosed with unilateral or bilateral adenoviral conjunctivitis at less than 1 week from onset were enrolled in this study. Patients were divided randomly into two groups; group 1 was treated with 1.5% levofloxacin with 0.1% fluorometholone administered four times a day and group 2 was treated with a sixfold dilution of polyvinyl alcohol iodine (PAI) solution with 0.1% fluorometholone four times a day. Conjunctival samples from all affected eyes were obtained for real-time PCR. The total scores of acute signs (i.e., eyelid edema, conjunctival injecton, conjunctival discharge, follicules, pseudomembranes, subconjunctival hemorrhage) and symptoms, HAdV DNA copy number, and the presence of multiple subepithelial corneal infiltrates (MSI) were evaluated every 5 visits up to Day 30 after diagnosis.

RESULTS

Comparing the total scores of acute signs and symptoms and viral load, we observed no significant differences between the two groups. At day 15 after diagnosis the proportion of patients with MSI in group 2 (35.7%) was significantly lower than in group 1 (0%).

CONCLUSIONS

The impact of topical iodine/steroid therapy on acute signs and symptoms associated with adenoviral conjunctivitis is limited and not substantially different in the responses to antibiotics/steroids. However, this regimen results in a significant decrease in the incidence of MSI during the subacute phase of infection.

Aqueous Chlorhexidine Compared with Povidone-Iodine as Ocular Antisepsis before Intravitreal Injection: A Randomized Clinical Trial

PURPOSE

Topical povidone-iodine (PI) is widely used as an ocular surface antiseptic for intravitreal injections (IVIs). Although PI is generally well tolerated, it can be associated with significant ocular irritation. Aqueous chlorhexidine (AqCHX) has been described as a possibly better tolerated antimicrobial for ophthalmic procedures. We compared patient pain scores, ocular surface characteristics, and antimicrobial efficacy between PI 5% and AqCHX 0.1% during IVIs.

DESIGN

Prospective single-center, randomized clinical trial.

PARTICIPANTS

Patients receiving same-day bilateral intravitreal anti-vascular endothelial growth factor (VEGF) injections.

METHODS

Each patient had 1 eye randomized to PI or AqCHX, and the second eye received the other agent. Both eyes received topical proparacaine 0.5%.

MAIN OUTCOME MEASURES

After IVIs, participants rated their pain (Wong-Baker, scale 0-10) for each eye 1 minute after PI or AqCHX instillation and 1 day after the procedure. Each eye was assessed using a standardized quantitative grading system of corneal epitheliopathy (ocular staining score). Microbial swab cultures of the conjunctiva both before instillation of topical antisepsis and 10 minutes after IVIs were given.

RESULTS

A total of 100 eyes of 50 patients were included. The mean patient age was 68 years (range, 39-92), and 30 of 50 (60%) were male. Compared with AqCHX, eyes receiving PI had a greater mean pain score immediately after injection (1.44 vs. 0.44, P < 0.001) but not on postprocedure day 1 (1.04 vs. 0.48, P = 0.06). Eyes that received PI had a higher ocular staining score indicating worse corneal epitheliopathy (4.22 vs. 3.10, P < 0.001). There was no difference in rates of positive microbial cultures between groups. There was no difference in rates of adverse events between groups (P = 0.99), and no cases of endophthalmitis occurred.

CONCLUSIONS

Povidone-iodine demonstrated greater ocular surface discomfort and corneal epitheliopathy compared with AqCHX during same-day bilateral IVIs. The 2 agents otherwise demonstrated no difference in positive microbial cultures or adverse events. Aqueous chlorhexidine may be a better tolerated alternative to PI for antimicrobial prophylaxis during IVIs for some patients.

Povidone iodine treatment is deleterious to human ocular surface conjunctival cells in culture

Objective

To determine the effect of povidone iodine (PI), an antiseptic commonly used prior to ocular surgery, on viability of mixed populations of conjunctival stratified squamous and goblet cells, purified conjunctival goblet cells and purified conjunctival stromal fibroblasts in primary culture.

Methods and analysis

Mixed population of epithelial cells (stratified squamous and goblet cells), goblet cells and fibroblasts were grown in culture from pieces of human conjunctiva using either supplemented DMEM/F12 or RPMI. Cell type was evaluated by immunofluorescence microscopy. Cells were treated for 5 min with phosphate-buffered saline (PBS); 0.25%, 2.5%, 5% or 10% PI in PBS; or a positive control of 30% H₂O₂. Cell viability was determined using Alamar Blue fluorescence and a live/dead kit using calcein/AM and ethidium homodimer-1 (EH-1).

Results

Mixed populations of epithelial cells, goblet cells and fibroblasts were characterised by immunofluorescence microscopy. As determined with Alamar Blue fluorescence, all concentrations of PI significantly decreased the number of cells from all three preparation types compared with PBS. As determined by calcein/EH-1 viability test, mixed populations of cells and fibroblasts were less sensitive to PI treatment than goblet cells. All concentrations of PI, except for 0.25% used with goblet cells, substantially increased the number of dead cells for all cell populations. The H₂O₂ control also significantly decreased the number and viability of all three types of cells in both tests.

Conclusion

We conclude that PI, which is commonly used prior to ocular surgeries, is detrimental to human conjunctival stratified squamous cells, goblet cells and fibroblasts in culture.

A new ophthalmic formulation containing antiseptics and dexpanthenol: In vitro antimicrobial activity and effects on corneal and conjunctival epithelial cells

Antibiotic resistance is increasing even in ocular pathogens, therefore the interest towards antiseptics in Ophthalmology is growing. The aim of this study was to analyze the in vitro antimicrobial efficacy and the in vitro effects of an ophthalmic formulation containing hexamidine diisethionate 0.05%, polyhexamethylene biguanide (PHMB) 0.0001% disodium edetate (EDTA) 0.01%, dexpanthenol 5% and polyvinyl alcohol 1.25% (Keratosept, Bruschettini, Genova, Italy) on cultured human corneal and conjunctival cells. The in vitro antimicrobial activity was tested on Staphylococcus aureus, Methicillin-Resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Streptococcus pneumoniae, Streptococcus pyogenes and Streptococcus mitis. For each microbial strain 10 μL of a 0.5 MacFarland standardized bacterial inoculum were incubated at 25 °C with 100 μL of ophthalmic solution for up to 6 h. After different periods of time, samples were inoculated on blood agar with 5% sheep blood. Moreover, a 0.5 MacFarland bacterial inoculum was seeded in triplicate on Mueller-Hinton Agar or on Mueller-Hinton Fastidious Agar; then a cellulose disc soaked with 50 μL of ophthalmic solution was applied on the surface of agar and plates were incubated for 18 h at 37 °C, in order to evaluate the inhibition of bacterial growth around the disc. Human corneal and conjunctival epithelial cells in vitro were incubated for 5, 10 and 15 min with Keratosept or its components. The cytotoxicity was assessed through the release of cytoplasmic enzyme lactate dehydrogenase (LDH) into the medium immediately after exposure to the drugs; the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to evaluate the metabolic cell activity. Our results show that Keratosept ophthalmic solution gave an average logarithmic (log) reduction of bacterial load of 2.14 ± 0.35 within 6 h of exposure (p-value < 0.05 versus control saline solution). On agar plates, all microbial strains, excluding P. Aeruginosa, showed an inhibition zone of growth around the Keratosept-soaked discs. Keratosept and its components after 5 and 10 min did not show any cytotoxic effect on cultured corneal and conjunctival cells, and only after 15 min a significant reduction of cell viability and an increase of cytotoxicity compared to control (vehicle) was seen; dexpanthenol 5% and polyvinyl alcohol accelerated the wounding of corneal cells in vitro. In conclusion, Keratosept showed good antimicrobial activity on the tested strains; the ophthalmic solution and its components were safe and non-toxic for the corneal and conjunctival epithelial cells for 5 and 10 min at the concentrations analyzed, and dexpanthenol 5% and polyvinyl alcohol promoted the wounding of corneal cells.

Evaluation of Retinal Function and Pathology After Intravitreal Injection of Povidone-Iodine and Polyvinyl Alcohol-Iodine in Rabbits

Purpose

This study compared intraocular toxicity of intravitreally injected povidone-iodine (PI) and polyvinyl alcohol-iodine (PAI) in rabbits.

Methods

In each rabbit, 0.1 mL of PI or PAI solution was injected intravitreally into one eye and saline was injected into the other. PI was tested at available iodine concentrations of 0.05%, 0.1%, 0.2%, and 0.5%, and PAI at 0.05%, 0.1%, and 0.2% (n = 6 each). Electroretinograms were recorded before injection and 1, 7, and 14 days after injection. Pathological examinations of eyeballs were performed on day 15.

Results

Mean b-/a-wave ratios of the electroretinograms did not change in eyes injected with 0.05%, 0.1%, or 0.2% PI (PI-0.05, PI-0.1, and PI-0.2, respectively) or in eyes injected with 0.05% or 0.1% PAI (PAI-0.05 and PAI-0.1, respectively) compared to saline-injected eyes, but was transiently impaired on day 1 in PAI-0.2 eyes. Histopathologically, no retinal abnormalities were observed in PI-0.05, PAI-0.05, or PAI-0.1 eyes. One PI-0.1 eye first showed localized inflammatory cell infiltration in the inferior retinal region. Two PI-0.2 eyes and one PAI-0.2 eye had retinal degeneration and inflammatory cell infiltration. In the PI-0.5 group, extensive inflammatory cell infiltration was observed in six eyes and inferior retinal detachment in five eyes.

Conclusions

PI and PAI have equivalent retinal toxicity profiles, and retinal toxicity first affects the inner retinal layer in the inferior region. The highest non-retinotoxic vitreous concentration is 0.0033% available iodine from intravitreal injection of PI or PAI containing 0.05% available iodine.

Translational Relevance

Low concentrations of PI or PAI can be used to wash the ocular surface during surgery or intravitreal injection to prevent endophthalmitis.

[Continuous anti-glaucoma drug therapy as a risk factor of dry eye]

A preservative is a mandatory component of the eye drops designed to prevent microbial contamination in an opened bottle. Most of the preservative agents are either detergents, or oxidants; the most widely used and well-studied preservative - benzalkonium chloride - is a detergent. Due to regular usage of glaucoma eye drops, cytotoxic impact of the preservatives on anterior eye surface is considered the principal cause of its pathology, which leads to a decrease in quality of life. The high cost of preservative-free pharmacological forms and the complicated process of developing new preservatives make the usage of eye drops with minimal required concentration of preservative agent and a moistening component a good compromise. The most commonly utilized moistening component is polyvinyl alcohol - synthetic polymeric hydrogel, which is also used in artificial tears and bioengineering.

Optimizing the antisepsis protocol: Effectiveness of 3 povidone-iodine 1.0% applications versus a single application of povidone-iodine 5.0

PURPOSE

To determine the minimum effective concentration of povidone-iodine that reduces the bacterial load by 3-log₁₀, the U.S. Food and Drug Administration requirement for antiseptic agents, and to study alternative dosing schedules of povidone-iodine to optimize its bactericidal effect.

SETTING

Microbiology Laboratory, Evanston Hospital, Evanston, Illinois, USA.

DESIGN

Experimental study.

METHODS

A standard 0.5 McFarland solution of Staphylococcus epidermidis was applied to blood agar plates. The plates were treated with a single application of povidone-iodine solutions from 10.0% to 0.1% to define the range of interest. Another set of plates received 3 applications of various povidone-iodine solutions. Microbial growth was evaluated after 24 hours. Standard deviations with 99.0% and 99.9% confidence intervals for each concentration were estimated and used to estimate the minimum concentration that reduced the colony counts by at least 3-log₁₀.

RESULTS

Povidone-iodine at 2.5% and higher concentrations was effective in eliminating S epidermidis with a single application. Three 30-second applications of povidone-iodine at concentrations of 0.7% and higher resulted in at least a 3-log₁₀ reduction of colonies.

CONCLUSIONS

Povidone-iodine 5.0% has been the standard of care for preoperative ocular antisepsis for 3 decades. Povidone-iodine 0.7% was as effective as a bactericidal agent when applied multiple times. This suggests povidone-iodine 1.0%, applied in three 30-second applications for preoperative surface disinfection might be as effective for preoperative antisepsis.

Preoperative topical liposomal ozone dispersion to reduce bacterial colonization in conjunctival sac and periocular skin: Preliminary study in dogs

Prophylaxis represents a keystone to reduce periocular skin and ocular conjunctiva bacterial load before surgical procedures. Despite many prophylactic agents are available the preferred perioperative ocular surface antimicrobial is still unknown. The purpose of this study was to assess the effectiveness of preoperative liposomal ozone dispersion in reducing bacterial colonization from the conjunctival sac and periocular skin in dogs, in comparison with povidone-iodine and fluoroquinolone. Twenty-two owned dogs consisting with 44 eyes in total scheduled for ophthalmic surgical procedure were enrolled for the study and divided in four groups receiving either ozone dispersion or povidone iodine in eyelid and conjunctiva, fluoroquinolone or placebo. A swab was taken before and after the antisepsis protocol evaluating total microbial count, coagulase positive and negative staphylococci. Statistical analysis revealed a significant decrease in colony forming units (CFU) for total microbial count, coagulase positive and negative staphylococci both for liposomal ozone dispersion and povidone iodine. No statistical differences were detected in median CFU for both one-day placebo and fluoroquinolone preoperative prophylactic topical therapy. The results of this preliminary study demonstrate that liposomal ozone-dispersion is as effective as povidone iodine to reduce preoperative bacterial load in ocular surface.

Polyvinyl alcohol-iodine induced corneal epithelial injury in vivo and its protection by topical rebamipide treatment

Periocular povidone-iodine (PI) and polyvinyl alcohol-iodine (PAI) have had a major role in the prevention of endophthalmitis. The purpose of this study was to investigate the corneal epithelial toxicity of PAI in a rabbit eye model using corneal resistance (CR) measurement, which is a good indicator of cell barrier function. Rabbit eyes were administered PAI solution at 4-, 6-, 8-, or 16-fold dilution with physiological saline solution (saline) or saline alone (control), to the conjunctival sac with/without wash-out with saline. Corneal epithelial injury assessed by fluorescein staining and the CR ratio was measured at 10 minutes (min) to 96 hours (h) after the initial administration. Histological observation was performed in the eyes following the PAI or control administrations. At 120 min after administration of PAI solution, the CR ratio was decreased and superficial punctate keratopathy (SPK) was significantly increased in each of the PAI-administered groups compared to the control. Recovery of CR and SPK after administration of 6- or 8-fold dilution of PAI was significantly delayed in eyes that were not subsequently washed with saline compared with eyes that were. Pre- or post-instillation of 2% rebamipide ophthalmic suspension significantly reduced PAI induced-SPK and -decrease of CR ratio. The CR method was able to accurately and quantitatively evaluate fine corneal epithelial injury. It is suggested that eyes should be washed with saline solution after administration of PAI solution or the instillation of rebamipide to prevent or reduce corneal epithelial injury.

Dry eye disease and oxidative stress

Dry eye, an age-related condition, is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance and tear film instability. Environmental factors are also often implicated in dry eye including exposure to pollutants, ultraviolet (UV) radiation and ozone as well as the chronic use of preserved eyedrops such as in the treatment of glaucoma. These factors increase oxidative stress and ocular surface inflammation. Here, we reviewed the cellular, animal and clinical studies that point to the role of oxidative stress in dry eye disease. The biomarkers used to indicate oxidative damage in ocular surface tissues include 8-hydroxy-2 deoxyguanosine (8-OHdG), 4-hydroxynonenal (HNE) and malondialdehyde (MDD). Antioxidative defences in the ocular surface occur in the form of tear proteins such as lactoferrin and S100A proteins, and enzymes such as superoxide dismutase (SOD), peroxidase, catalase and mitochondrial oxidative enzymes. An imbalance between the level of reactive oxygen species (ROS) and the action of protective enzymes will lead to oxidative damage, and possibly inflammation. A small number of interventional studies suggest that oxidative stress may be directly targeted in topical therapy of dry eye treatment. For example, in vitro studies suggest that L-carnitine and pterostilbene, a blueberry component may reduce oxidative stress, and in animal studies, alpha-lipoic acid (ALP) and selenoprotein P may be helpful. Examples of treatments used in clinical trials include vitamin B12 eyedrops and iodide iontophoresis. With recent emphasis on ageing medicine and preventive holistic health, as well as the role of environmental science, research on oxidative stress in the ocular surface is likely to have increasing impact in the coming years.

The effect of intravitreal injections on dry eye, and proposed management strategies

Intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agents has become a commonly used treatment method for a number of ophthalmic conditions, including age-related macular degeneration. Although anti-VEGF therapy has shown promising results for many patients, there are several aspects of its application that have not been thoroughly investigated. One of these is the development and/or escalation of concurrent dry eye syndrome. Many patients undergoing treatment are already predisposed to dry eye disease due to their age and overall ocular health. As dry eye can have a substantial impact on quality of life, it has become increasingly apparent that the clinical signs and symptoms should be closely monitored and aggressively managed. This will allow for the optimization of patient comfort and visual potential. Here, we discuss the reasons why dry eye may develop during the course of repeated ocular anti-VEGF therapy, highlighting the key concerns about current practices and proposing possible solutions to improve the outcome for the patients.

Ocular surface effects of repeated application of povidone iodine in patients receiving frequent intravitreal injections

BACKGROUND

The aim of this study was to investigate the patient reported symptoms and objective signs of tear film and ocular surface abnormalities experienced by patients undergoing repeated exposure to povidone iodine as a consequence of requiring frequent intravitreal injections for wet macular degeneration.

METHODS

This was a prospective study of consecutive patients who had received recent povidone 5% solution for sterile preparation of intravitreal injection less than 3 months prior to inclusion with a total of at least 3 intravitreal injections for macular degeneration. Each patient had one study eye which was undergoing regular intravitreal injection and a fellow eye which was not undergoing any injections. Each patient underwent evaluations of various tear film parameters on a single occasion for both eyes. The primary outcome was severity of dry eye symptoms as measured by the Schein dry eye questionnaire. The secondary outcomes were tear film osmolarity and corneal punctate staining using the Oxford Grading Scale.

RESULTS

A total of 90 patients were included in the study. 43.3% n = 39, were using ocular lubricating medication on a regular basis. A significantly greater proportion of study eyes had a Schein dry eye questionnaire score of 7 or higher; 12.2%, n = 11 amongst study eyes vs 4.4%, n = 4 amongst control, fellow eyes (p < 0.05). In terms of secondary outcomes, the study eyes had a slightly higher mean tear film osmolality compared to control, fellow eyes: 305.5 ± 1.7 in study eyes vs 302 ± 1.6 in control eyes although this difference was not statistically significant (p = 0.087). The study eyes had statistically significantly worse corneal staining as determined by the Oxford grading scale; 0.69 in study eyes vs 0.58 in control, fellow eyes (p = 0.02).

CONCLUSION

Our results confirm the detrimental impact of repeated application of povidone iodine for intravitreal injection procedures on symptoms of dry eyes as experienced and reported by patients.