Endophthalmitis Prophylaxis for Cataract Surgery

Carbon Monoxide Releasing Molecule-3 Alleviates Oxidative Stress and Apoptosis in Selenite-Induced Cataract in Rats via Activating Nrf2/HO-1 Pathway

PURPOSE

This study investigated the protective effect of carbon monoxide releasing molecule-3 (CORM-3), the classical donor of carbon monoxide, on selenite-induced cataract in rats and explore its possible mechanism.

METHODS

Sprague-Dawley rat pups treated with sodium selenite (Na2SeO3) were chosen as the cataract model. Fifty rat pups were randomly divided into 5 groups: Control group, Na2SeO3 (3.46 mg/kg) group, low-dose CORM-3 (8 mg/kg/d) + Na2SeO3 group, high-dose CORM-3 (16 mg/kg/d) + Na2SeO3 group, and inactivated CORM-3 (iCORM-3) (8 mg/kg/d) + Na2SeO3 group. The protective effect of CORM-3 was tested by lens opacity scores, hematoxylin and eosin staining, TdT-mediated dUTP nick-end labeling assay, and enzyme-linked immunosorbent assay. Besides, quantitative real-time PCR and western blotting were used for mechanism validation.

RESULTS

Na2SeO3 induced nuclear cataract rapidly and stably, and the achievement ratio of Na2SeO3 group was 100%. CORM-3 alleviated lens opacity of selenite-induced cataract and attenuated the morphological changes of the rat lens. The levels of antioxidant enzymes GSH and SOD in rat lens were also increased by CORM-3 treatment. CORM-3 significantly reduced the ratio of apoptotic lens epithelial cells, besides, CORM-3 decreased the expression of Cleaved Caspase-3 and Bax induced by selenite and increased the expression of Bcl-2 in rat lens inhibited by selenite. Moreover, Nrf-2 and HO-1 were upregulated and Keap1 was downregulated after CORM-3 treatment. While iCORM-3 did not exert the same effect as CORM-3.

CONCLUSIONS

Exogenous CO released from CORM-3 alleviates oxidative stress and apoptosis in selenite-induced rat cataract via activating Nrf2/HO-1 pathway. CORM-3 may serve as a promising preventive and therapeutic strategy for cataract.

Ochrobactrum anthropi: A Rare Cause of Culture-Proven Acute Post-Operative Cluster Endophthalmitis

AIM

To report the clinical presentation and management outcomes of an outbreak of culture-proven post-operative endophthalmitis (POE) secondary to Ochrobactrum anthropi.

METHODS

This study was conducted at a tertiary-care eye hospital in South India.

RESULTS

Fifty-five patients underwent cataract surgery by six surgeons on three consecutive days in the same surgical facility in September 2020. Four patients developed POE after a mean interval of 12.0 ± 4.8 days and underwent immediate vitreous tap and intravitreal antibiotic injections (Vancomycin and Ceftazidime). All patients required a core vitrectomy (culture positive, n = 4/4). Two patients underwent an additional intraocular lens explantation, 2 and 4 months after presentation. All the four patients showed good anatomical and functional recoveries (mean follow-up, 5.75 ± 1.5 months). Two other patients had an exaggerated post-operative inflammation, which was successfully treated with topical medications.

CONCLUSIONS

O. anthropi is a rare cause of acute POE. Although the isolated organism was multi-drug resistant, the outcome was good in all the patients.

Ferulic Acid Protects Human Lens Epithelial Cells against Ionizing Radiation-Induced Oxidative Damage by Activating Nrf2/HO-1 Signal Pathway

Ionizing radiation- (IR-) induced oxidative stress has been recognized as an important mediator of apoptosis in lens epithelial cells (LECs) and also plays an important role in the pathogenesis of IR-induced cataract. Ferulic acid (FA), a phenolic phytochemical found in many traditional Chinese medicine, has potent radioprotective and antioxidative properties via activating nuclear factor erythroid 2-related factor 2 (Nrf2) signal pathway. The goals of this study were to determine the protective effect of FA against IR-induced oxidative damage on human lens epithelial cells (HLECs) and to elucidate the role of Nrf2 signal pathway. HLECs were subjected to 4 Gy X-ray radiation with or without pretreatment of FA. It was found that FA pretreatment protected HLECs against IR-induced cell apoptosis and reduced levels of ROS and MDA caused by radiation in a dose-dependent manner. IR-dependent attenuated activities of antioxidant enzymes (SOD, CAT, and GPx) and decreased ratio of reduced GSH/GSSG were increased by pretreatment of FA. FA inhibited IR-induced increase of Bax and cleaved caspase-3 and the decrease of Bcl-2 in a dose-dependent manner. Furthermore, FA provoked Nrf2 nuclear translocation and upregulated mRNA and protein expressions of HO-1 in a dose-dependent manner. These findings indicated that FA could effectively protect HLECs against IR-induced apoptosis by activating Nrf2 signal pathway to inhibit oxidative stress, which suggested that FA might have a therapeutic potential in the prevention and alleviation of IR-induced cataract.

The effect of postoperative oral antibiotic therapy on the incidence of postoperative endophthalmitis after phacoemulsification surgery in dogs: 368 eyes (1997-2010)

Purpose

To assess the effectiveness of postoperative administration of oral antibiotics at reducing the incidence of endophthalmitis following phacoemulsification cataract extraction in dogs.

Methods

Medical records of the University of Tennessee College of Veterinary Medicine were reviewed for cases having undergone phacoemulsification and divided according to whether or not they had received oral antibiotics postoperatively. Records were then evaluated for a diagnosis of endophthalmitis and incidence rates between the group receiving postoperative oral antibiotics and the group not receiving postoperative oral antibiotics were compared.

Results

A total of 215 patients (368 eyes) were identified by the search. One-hundred twelve patients (197 eyes) were treated with oral antibiotics postoperatively. One-hundred and three patients (171 eyes) were not treated with oral antibiotics postoperatively. Three cases of endophthalmitis were identified, with one in the antibiotic-treated group and two in the non-antibiotic treated group (P > 0.05, Fisher’s exact test).

Conclusions

The overall incidence of endophthalmitis at the University of Tennessee from 1997–2010 was 0.82%. The rate of post-phacoemulsification endophthalmitis was unaffected by the postoperative administration of oral antibiotics.

Predisposing Factors for Severe Complications after Cataract Surgery: A Nationwide Population-Based Study

We conducted a retrospective group study to evaluate the potential systemic risk factors for major postoperative complications of cataract surgery. Individuals diagnosed with (n = 2046) and without (n = 8184) serious complications after cataract surgery were matched 1:4 for age, sex, and index date obtained using Taiwan’s National Health Insurance Research Database. The outcome was defined as at least one new inpatient or outpatient diagnosis of systemic disease one year before the index date. The effect of demographic data on postoperative complications was also analyzed in the multivariable model. Data were analyzed using univariate and multivariate conditional logistic regression models to calculate odds ratios (ORs) and 95% confidence intervals of the risk of developing serious complications. After the entire study interval, the major postoperative complications of cataract surgery were associated with the following systemic diseases: hypertension (adjusted OR (aOR) = 2.329, p < 0.001), diabetes mellitus (aOR = 2.818, p < 0.001), hyperlipidemia (aOR = 1.702, p < 0.001), congestive heart failure (aOR = 2.891, p < 0.001), rheumatic disease (aOR = 1.965, p < 0.001), and kidney disease needing hemodialysis (aOR = 2.942, p < 0.001). Additionally, demographic data including old age, higher urbanization level, higher level of care, and more frequent inpatient department visits were associated with a higher rate of postoperative complications. In conclusion, metabolic syndrome, chronic heart failure, end-stage renal disease, rheumatic disease, older age, and frequent inpatient department visits are correlated with the development of severe postoperative complications of cataract surgery. Therefore, cataract surgery patients should be informed about a higher possibility of postoperative complications.

Effectiveness of 0.66% Povidone-Iodine Eye Drops on Ocular Surface Flora before Cataract Surgery: A Nationwide Microbiological Study

A multicenter, nonrandomized, prospective, controlled study was conducted to evaluate, as perioperative prophylactic treatment, the anti-infective effectiveness of 0.66% povidone-iodine eye drops (IODIM^®) against the bacterial flora of the conjunctival surface of patients who undergo cataract surgery. Eye drops containing 0.66% povidone-iodine were applied to the eye undergoing cataract surgery; the untreated contralateral eye was used as control. One hundred and twenty patients set to receive unilateral cataract surgery were enrolled in 5 Italian Ophthalmology Centers and pretreated for three days with 0.66% povidone-iodine eye drops. The contralateral eye, used as control, was left untreated. Conjunctival swabs of both eyes were collected at the baseline visit and after three days of treatment, just before the cataract surgery. A qualitative and quantitative microbiological analysis of bacterial presence was evaluated by means of bacterial culture, followed by identification. Methicillin resistance determination was also performed on staphylococci isolates. Bacterial load before and after treatment of the eye candidate for cataract surgery was evaluated and compared to the untreated eye. A reduction or no regrowth on the culture media of the bacterial load was observed in 100% of the study subjects. A great heterogenicity of bacterial species was found. The 0.66% povidone-iodine eye drops, used for three days prior to cataract surgery, were effective in reducing the conjunctival bacterial load. The 0.66% povidone-iodine eye drops (IODIM^®) might represent a valid perioperative prophylactic antiseptic adjuvant treatment to protect the ocular surface from microbial contamination in preparation of the surgical procedure.

Postoperative Endophthalmitis and Toxic Anterior Segment Syndrome Prophylaxis: 2020 Update

Improved surgical techniques have led to an increase in the number of outpatient ophthalmic procedures. In spite of decreased surgical times and overall improved outcomes, endophthalmitis remains one of the most severe complications of ophthalmic surgery. Although there are well known risk factors for postoperative endophthalmitis, some prophylaxis strategies remain controversial. A category of noninfectious postoperative inflammation, known as toxic anterior segment syndrome (TASS), is a rare but important complication of cataract surgery. While several worldwide outbreaks of TASS have occurred, it is challenging to identify an etiology in order to reduce the risk of further cases. Endophthalmitis and TASS cannot be prevented completely, but their rates may be decreased through risk reduction strategies supported by peer-reviewed evidence. This review highlights the current evidence in the prevention strategies for postoperative endophthalmitis and TASS.

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.

Antibiotic prophylaxis practice patterns for cataract surgery in India - Results from an online survey

Purpose:

The aim of this study is to assess the current antibiotic prophylaxis practice patterns for cataract surgery in India.

Methods:

This was a questionnaire-based E-survey carried out at a tertiary eye care center in India. An E-mail invitation to complete an online 20 point questionnaire survey was sent to all members of the All India Ophthalmological Society with valid E-mail addresses using a digital E-mail service. Duplicate entries were prevented.

Results:

Out of 1228 total respondents (8.2%) who completed the survey 38% reported using routine intracameral (IC) antibiotic prophylaxis. Another 7% place antibiotics in the irrigating solution. Of those using IC antibiotic prophylaxis, 91% adopted this practice within the past 2 years; 92% are using moxifloxacin with 56% using a commercially available moxifloxacin formulation. Those predominantly performing phacoemulsification (43% vs. 25% performing mostly manual small incision cataract surgery, P < 0.001) and more than 500 cataract surgeries annually (45% vs. 33%, P < 0.001) reported greater use of IC moxifloxacin. Self-reported endophthalmitis rates were statistically significantly greater in those not using IC antibiotics (0.045% vs. 0.036, P = 0.04). Although a majority of respondents believe that IC antibiotics are an important option (54%) and that it is important to have a commercially available solution (68%), many believe that other antibiotic prophylaxis methods are sufficient (31%).

Conclusion:

IC antibiotic prophylaxis for cataract surgery has sharply increased in India. In contrast to the West, intraocular moxifloxacin, which is commercially available in India, is preferred by the vast majority of users.

Antibiotic prophylaxis in cataract surgery - An evidence-based approach

Various protocols are being followed for endophthalmitis prophylaxis in cataract surgery, and this subject continues to be a matter of debate. We summarize the most recent evidence-based studies on this topic with additional stress on intracameral (IC) antibiotic prophylaxis. Here, we discuss several large, international clinical studies which discuss the efficacy, adoption, safety, cost, and newer trends in antibiotic prophylaxis. Majority of these studies report a significant reduction in endophthalmitis rates with IC antibiotic prophylaxis. Efficacy data have been reported for IC cefuroxime, vancomycin, and moxifloxacin. Surgeons are now looking for alternatives to vancomycin for IC prophylaxis because of its association with the rare but sight-threatening complication of hemorrhagic occlusive retinal vasculitis. A recent large clinical study shows convincing efficacy with IC moxifloxacin prophylaxis. Two large studies have also reported significant endophthalmitis reduction following use of IC antibiotic prophylaxis, in eyes with posterior capsule tear which are at highest risk for infection. Except for one randomized controlled trial, there is a lack of prospective data on this subject; however, considering the complexity of performing such studies, surgeons have to rely on the mounting evidence from other recent big data studies. Availability of approved intraocular antibiotic formulations will see a much higher adoption in the future.