Relative efficacy of intracameral moxifloxacin injection methods.

PURPOSE: To determine the amount of moxifloxacin remaining in the anterior chamber (AC), immediately after its injection using 3 current injection methods, assuming mixing and fluid exchange with the AC contents during injection of the drug, and to determine the most desirable injection method. SETTING: Department of Ophthalmology and Vision Sciences and Institute of Biomedical Engineering, University of Toronto, Toronto, Canada. DESIGN: Mathematical modeling. METHODS: Mathematical modeling using first-order mixing methods were used to assess mixing. RESULTS: The Kaiser method of injecting 0.5 mL × 100 µg/0.1 mL does not achieve the desired 500 µg level of moxifloxacin in the AC. The "straight from the bottle" method of injecting 0.1 mL × 500 µg/0.1 mL is fraught with potential error, yielding a relatively unreliable final amount in the AC. Injecting 0.5 to 0.6 mL × 150 µg/0.1 mL yields a result closest to the desired goal. CONCLUSIONS: Based on the calculation, the most accurate of current methods to deliver 500 µg moxifloxacin intracamerally is the method of 150 µg/0.1 mL × 0.5 to 0.6 mL.

Bilateral simultaneous postoperative endophthalmitis: review of cases reported over the past 50 years.

A detailed retrospective analysis and literature review were conducted for all previously published reports of bilateral simultaneous postoperative endophthalmitis (BSPOE) since 1970. There have been 7 (9, with 2 currently being reported elsewhere) cases of BSPOE after immediately sequential bilateral cataract surgery (ISBCS) reported over 50 years. Generally, in these cases, the surgical protocol recommended by the International Society of Bilateral Cataract Surgeons ( i SBCS) was breached or uncertain. Bacterial causes were Pseudomonas aeruginosa (3), Staphylococcus epidermidis (3), and Burkholderia cepacia complex (1). One case showed negative results for bacterial infection and 1 was not determined. Visual recovery was light perception, or worse, for Pseudomonas cases, generally good for Staphylococcus and Burkholderia cases, and mixed in cases of unknown etiology. Therefore, BSPOE is rare and causes vary. Strict adherence to the i SBCS General Principles of Excellence in ISBCS 2009 surgical protocol and care with operating room construction seem to considerably lessen the risk.

Multicenter Comparison of the Toronto Portable Perimeter with the Humphrey Field Analyzer: A Pilot Study.

PURPOSE: To evaluate the agreement between glaucomatous 24-2 visual field (VF) testing performed with the Toronto Portable Perimeter (TPP; VEM Medical Technologies) and the Humphrey Field Analyzer (HFA; Carl Zeiss Meditec). DESIGN: Multicenter prospective cohort analysis. PARTICIPANTS: Patients with suspected or confirmed glaucoma treated at Prism Eye Institute (Oakville, Canada), York Finch Eye Associates (North York, Canada), or the Ontario Mobile Medical Eye Care Unit (Cochrane, Canada) between March 2019 and March 2020. METHODS: Patients underwent consecutive VF tests on the same eye using the HFA Swedish Interactive Threshold Algorithm Standard 24-2 test and TPP Standard 24-2 test in randomized order. Bland-Altman analysis and paired t tests were used to compare VF results obtained by the TPP and the HFA. Participants completed a 5-question validated questionnaire after completing both testing methods. MAIN OUTCOME MEASURES: Mean difference and degree of agreement in mean deviation (MD), pattern standard deviation (PSD), visual field index (VFI), and test duration between VF modalities. RESULTS: One hundred fifty eyes from 91 patients were included in analysis. Average MD of the overall cohort using HFA and TPP VF testing was -4.32 ± 5.47 dB and -4.53 ± 5.22 dB, respectively (P = 0.74). Bland-Altman analysis showed good agreement between HFA and TPP tests. The mean differences (95% limits of agreement) between HFA and TPP for MD, PSD, VFI, and test duration were 0.21 dB (-4.25 to 4.67 dB), -0.13 dB (-3.72 to 3.47 dB), 0.66% (-10.94% to 12.26%), and 0.65 seconds (-97.51 to 98.81 seconds), respectively. No statistically significant mean difference was found between HFA and TPP tests for MD, PSD, VFI, or test duration. Mean deviation (R2 = 0.830) and VFI (R2 = 0.866) were correlated strongly with both modalities. Questionnaire results demonstrated that patients significantly preferred the TPP over the HFA for VF testing (P < 0.001). CONCLUSIONS: Mean deviation, PSD, and VFI outcomes measured by the TPP were statistically similar to corresponding parameters obtained with the HFA. Test time duration did not differ significantly between the TPP and HFA, and patients significantly preferred the TPP to the HFA examination experience. These pilot results suggest that the TPP may offer an accessible alternative to HFA VF testing.

Immediately sequential bilateral cataract surgery: an academic teaching center's experience.

PURPOSE: To evaluate the safety and outcomes of immediately sequential bilateral cataract surgery (ISBCS) at a Canadian academic teaching center. SETTING: Tertiary university teaching hospital of Laval University, Quebec City, Canada. DESIGN: Retrospective cohort study. METHODS: 2003 consecutive patients (4006 eyes) who underwent ISBCS under topical anesthesia from January 2019 to December 2019 were included. All charts were retrospectively reviewed. Outcome measures included intraoperative and postoperative complications, postoperative uncorrected distance (UCVA) and pinhole (PHVA) visual acuities, and autorefraction measurements. RESULTS: 4006 eyes from 1218 (60.8%) female and 785 (39.2%) male patients with a mean age of 74 ± 8 years had a mean preoperative visual acuity of 0.503 logMAR (Snellen 20/63). The mean axial length was 23.53 ± 1.37 mm. Most eyes had monofocal intraocular lenses (IOLs) implanted (n = 3738, 93.3%) followed by toric (n = 226, 5.6%), multifocal (n = 25, 0.6%), and multifocal toric (n = 17, 0.4%) IOLs. Intraoperative complications included 14 (0.3%) posterior capsule ruptures with 5 (0.1%) requiring sulcus IOL placement, and 7 (0.2%) partial zonulysis, with 3 requiring capsular tension rings (0.07%). There were no cases of endophthalmitis or toxic anterior segment syndrome. Mean 5-week postoperative UCVA was 0.223 (Snellen 20/33), PHVA was 0.153 (Snellen 20/28) with a mean spherical equivalent of -0.21 diopters. CONCLUSIONS: ISBCS performed following International Society of Bilateral Cataract Surgeons recommended guidelines is a safe procedure. This cohort of 4006 eyes had very few complications, with none attributable to the surgery being done bilaterally. The UCVA, PHVA, and refractive outcomes were good.

Incremental effect of topical and oral moxifloxacin administration with surgical intracameral prophylaxis.

OBJECTIVE: To determine how supplemental perioperative topical or oral moxifloxacin administration impacts anterior chamber (AC) antibiotic concentrations beyond those achieved by intracameral (IC) administration alone for postoperative endophthalmitis (POE) prophylaxis. DESIGN: Mathematical modeling. METHODS: The mathematical model developed by Arshinoff, Modabber, and Felfeli was adapted to calculate all reported data. A literature review of pharmacokinetic data for topical and oral moxifloxacin was used to inform the expansion of the model. RESULTS: Our previously constructed IC model yields a dose of moxifloxacin in the AC sufficient to confer bactericidal coverage against the most common POE pathogen, methicillin-sensitive Staphylococcus aureus (MSSA), for ∼40 hours postoperatively. Topical 0.5% moxifloxacin eye drops alone, administered every 4 or 6 hours, achieve an AC concentration just above or at the mutant prevention concentration (MPC) for MSSA, respectively, whereas 8-hour dosing produces levels generally below the MPC. Combining topical moxifloxacin with IC increases the AC concentration above IC alone only after 20 or more hours and maintains the AC concentration at, or just below, the MPC for MSSA for as long as the drops are continued. Combined perioperative oral moxifloxacin with IC increases AC levels over IC alone only after 16 hours and maintains the AC concentration above the MPC for MSSA for an additional 5 hours, owing to the systemic reservoir. CONCLUSIONS: The addition of topical or oral moxifloxacin supplemental to IC can extend the duration of bactericidal coverage for the most common, but not the most resistant POE-causing pathogens.

Rheological behavior of commercial artificial tear solutions.

PURPOSE: To measure the rheological behavior of artificial tears to gain insight into the potential role of rheology in predicting the efficacy of artificial tear solutions for the treatment of dry-eye disease (DED). SETTING: Research laboratories of I-MED Pharma, Canada, Rohn and Associates, Inc., New Jersey, and Hydan Technologies, New Jersey. DESIGN: Laboratory investigation. METHODS: Twenty commercially available artificial tear drops were purchased in Canada and the United Kingdom. Rheological measurements of viscosity and normal stress as a function of shear rate were performed at 25°C. RESULTS: For comparison of the rheological behavior, the various artificial tears were sorted into 3 groups: group A, which exhibit significant non-Newtonian shear-thinning behavior; group B, which exhibit moderate non-Newtonian shear-thinning behavior; and group C, which exhibit Newtonian behavior throughout the shear rate range. Results of normal stress difference, N1, as a function of shear rate were concordant with the rheological testing, indicated the viscoelastic nature of the samples in groups A and B, whereas members of group C did not exhibit any elasticity. CONCLUSIONS: The various artificial tear solutions were sorted into groups based on their Newtonian or non-Newtonian behaviors. The results suggest that non-Newtonian solutions should provide better comfort and longer-lasting symptomatic relief for DED. It remains to be confirmed clinically if there is a direct correlation between the rheological behavior of artificial tears and their ability to provide prolonged relief in DED, or if other factors are more important.

Role of rheology in tears and artificial tears.

The study of viscoelastic fluids as artificial tears dates back to the late 1970s. Healon, the first ophthalmic viscosurgical device, was approved in 1980, but studied extensively before then, exhibits very interesting shear-thinning properties that were found to be beneficial in both ophthalmic surgery and somewhat later as a tear replacement solution. Unlike the previous tear film replacements, which were mainly viscous in nature, viscoelastic solutions, particularly those based on hyaluronan, exhibited very interesting, potentially beneficial, rheological properties, especially when slightly altered to become elastoviscous. This review examines the rheological properties that are significant in artificial tear solutions. We define herein the necessary parameters that need to be further studied to design and formulate rheologically better artificial tears, which should provide enhanced efficacy compared with their predecessors.

Aqueous level abatement profiles of intracameral antibiotics: A comparative mathematical model of moxifloxacin, cefuroxime, and vancomycin with determination of relative efficacies.

PURPOSE: To create a model of the abatement profiles of the three most commonly employed endophthalmitis prophylaxis intracameral (IC) antibiotics-cefuroxime, vancomycin, and moxifloxacin-to enable comparison of their durations of efficacy against common endophthalmitis pathogens. SETTINGS: Humber River Hospital and The Eye Foundation of Canada, Toronto, Ontario, the University of Toronto, Ontario, and McGill University, Montreal, Quebec, Canada. DESIGN: Literature review, as well as review of our clinical experience with 4797 consecutive cases with IC vancomycin, followed by 9185 consecutive cases with IC moxifloxacin. METHODS: A detailed review of the prophylactic antibiotic literature was performed. Exponential decay models of the selected IC antibiotics were updated from previous work by the study authors with decay constants adjusted to agree with the available published objective data. RESULTS: The graphs generated by the study data demonstrate the relative duration of IC bactericidal activity of moxifloxacin, cefuroxime, and vancomycin. They suggest that at present, IC moxifloxacin, when administered in appropriate doses, is the most effective agent in preventing postoperative endophthalmitis. Unlike vancomycin and cefuroxime, bacterial resistance to moxifloxacin is dose-dependent, and it is overcome in the vast majority of cases with doses that can safely be achieved intracamerally. The graphs can serve as a useful tool to assess the expected efficacy of each antibiotic in reference to local pathogen resistances. CONCLUSION: The model shows IC moxifloxacin, cefuroxime, and vancomycin durations of bactericidal efficacy post-cataract surgery, which correlate well with the published objective data.

Refractive Laser-Assisted Cataract Surgery versus Conventional Manual Surgery: Comparing Efficacy and Safety in 3144 Eyes.

PURPOSE: To report on outcomes of the efficacy and safety in 1 of the largest series of eyes undergoing either conventional manual cataract surgery (MCS) or refractive femtosecond laser-assisted cataract surgery (ReLACS). DESIGN: Retrospective, consecutive, interventional comparative case series. METHODS: This study included 3144 consecutive eyes, of which 1580 were treated via MCS, and 1564 were treated via ReLACS at Uptown Surgical Centre in Vaughan, Ontario, Canada. Preoperative characteristics, best corrected visual acuity (BCVA), mean absolute spherical error (MAE), rates of intraoperative posterior capsular rupture, and postoperative complications were evaluated. RESULTS: Across all eyes, ReLACS was superior to MCS for reducing surgical time (MCS: 7.7 ± 0.1 min vs ReLACS: 6.8 ± 0.1 min, P < 0.001); was less commonly associated with postoperative cystoid macular edema (OR = 0.36, 95% CI: 0.14-0.91, P = 0.031) and more commonly reduced MAE (MCS: 0.60 ± 0.02 diopters (D) vs ReLACS: 0.54 ± 0.02 D, P = 0.02). There were no differences in rates of posterior capsular rupture (P = 0.918), overall postoperative complications (P = 0.088) or final BCVA (P = 0.881). When analyzing a subgroup of more difficult cases (n = 833), ReLACS was superior to MCS for: 1) being more likely to yield an improvement of more than 0.1 logarithm of the minimum angle of resolution BCVA (OR = 1.80, 95% CI: 1.15-2.74, P = 0.01); 2) reducing MAE (MCS: 0.73 ± 0.3 D vs ReLACS: 0.60 ± 0.27 D, P = 0.04); and 3) being more likely to yield an MAE within 0.5 D (OR = 1.61, 95% CI: 1.11-2.33, P = 0.012). CONCLUSIONS: Across all eyes, our results support that ReLACS and MCS yield similar outcomes. However, our results show trends toward a more pronounced benefit of ReLACS compared to MCS when treating more difficult eyes.

Endophthalmitis Prophylaxis in Cataract Surgery: Overview of Current Practice Patterns Around the World.

BACKGROUND: Acute-onset postoperative endophthalmitis after cataract surgery remains a rare but important cause of visual loss. There is no global consensus regarding the optimal strategies for prophylaxis of endophthalmitis and practices vary substantially around the world, especially with respect to the use of intracameral antibiotics. The European Society of Cataract & Refractive Surgeons in a randomized clinical trial (2007) reported an approximately 5-fold reduction in endophthalmitis rates associated with the use of intracameral cefuroxime. Despite this report, the use of intracameral antibiotics has not been universally adopted. METHODS: Various endophthalmitis prophylaxis patterns around the world (including the United States, Canada, Australia/New Zealand, Japan, China, India, Indonesia, South Africa, Argentina, Russia, Sweden and Mexico) are compared. Each contributing author was asked to provide similar information, including endophthalmitis rates based on published studies, current practice patterns, and in some cases original survey data. Various methods were used to obtain this information, including literature reviews, expert commentary, and some new survey data not previously published. RESULTS: Many different practice patterns were reported from around the world, specifically with respect to the use of intracameral antibiotics. CONCLUSION: There is no worldwide consensus regarding endophthalmitis prophylaxis with cataract surgery.