Surgical Outcomes among Focused versus Diversified Cataract Surgeons.

PURPOSE: Narrowly focused surgical practice has become increasingly common in ophthalmology and may have an effect on surgical outcomes. Previous research evaluating the influence of surgical focus on cataract surgical outcomes has been lacking. This study aimed to evaluate whether surgeons' exclusive surgical focus on cataract surgery influences the risk of cataract surgical adverse events. DESIGN: Population-based cohort study. PARTICIPANTS: All patients 66 years of age or older undergoing cataract surgery in Ontario, Canada, between January 1, 2002, and December 31, 2013. METHODS: Outcomes of isolated cataract surgery performed by exclusive cataract surgeons (no other types of surgery performed), moderately diversified cataract surgeons (1%-50% noncataract procedures), and highly diversified cataract surgeons (>50% noncataract procedures) were evaluated using linked healthcare databases and controlling for patient-, surgeon-, and institution-level covariates. Surgeon-level covariates included both surgeon experience and surgical volume. MAIN OUTCOME MEASURES: Composite outcome incorporating 4 adverse events: posterior capsule rupture, dropped lens fragments, retinal detachment, and suspected endophthalmitis. RESULTS: The study included 1 101 864 cataract operations. Patients had a median age of 76 years, and 60.2% were female. Patients treated by the 3 groups of surgeons were similar at baseline. Adverse events occurred in 0.73%, 0.78%, and 2.31% of cases performed by exclusive cataract surgeons, moderately diversified surgeons, and highly diversified surgeons, respectively. The risk of cataract surgical adverse events for patients operated on by moderately diversified surgeons was not different than for patients operated on by exclusive cataract surgeons (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.00-1.18). Patients operated on by highly diversified surgeons had a higher risk of adverse events than patients operated on by exclusive cataract surgeons (OR, 1.52; 95% CI, 1.09-2.14). This resulted in an absolute risk difference of 0.016 (95% CI, 0.012-0.020) and a number needed to harm of 64 (95% CI, 50-87). CONCLUSIONS: Exclusive surgical focus did not affect the safety of cataract surgery when compared with moderate levels of surgical diversification. The risk of cataract surgical adverse events was higher among surgeons whose practice was dedicated mainly to noncataract surgery.

Evolution in the Risk of Cataract Surgical Complications among Patients Exposed to Tamsulosin: A Population-Based Study.

PURPOSE: Tamsulosin is associated with intraoperative floppy iris syndrome (IFIS), an important risk factor for complications during cataract surgery. Significant efforts have been made to increase awareness of the risks associated with tamsulosin, and educational initiatives have fostered the uptake of technical adjustments to decrease adverse event rates among tamsulosin-exposed patients. However, the effectiveness of these efforts at the population level has not been studied. DESIGN: Population-based study to evaluate cataract surgical adverse event rates over time among patients exposed to tamsulosin and those not exposed to this drug. PARTICIPANTS: All male patients 66 years of age and older undergoing cataract surgery in Ontario, Canada, between January 1, 2003, and December 31, 2013, were included in the study. METHODS: Linked healthcare databases were used to study the evolution in the risk of cataract surgical adverse events over time among tamsulosin-exposed and non-tamsulosin-exposed patients adjusting for patient-, surgeon-, and institution-level covariates. The study timeframe incorporated periods before and after the first reports of tamsulosin-associated IFIS. MAIN OUTCOME MEASURES: Four important cataract surgical adverse events were evaluated: posterior capsule rupture, dropped lens fragments, retinal detachment, and suspected endophthalmitis. RESULTS: Among patients exposed to tamsulosin, the risk of surgical adverse events decreased over time (odds ratio, 0.95 per year; 95% confidence interval, 0.91-0.99 per year). This trend was observed across patient age strata. Among patients not recently exposed to tamsulosin, the risk of surgical adverse events also decreased over time (odds ratio, 0.96 per year; 95% confidence interval, 0.95-0.98 per year). CONCLUSIONS: The risk of cataract surgical complications among both tamsulosin-exposed and non-tamsulosin-exposed patients declined between 2003 and 2013. Tamsulosin remains an important risk factor for cataract surgical adverse events, and ongoing efforts will be needed to develop and disseminate surgical approaches that mitigate the risks posed by tamsulosin.

Cataract Surgery Quality and Capacity.

Cataract surgery is the most common operation performed in most developed countries, including Canada. Nuanced, evidence-driven policies are needed to ensure appropriate access to this sight-saving operation while maintaining the highest standards in quality of care. The Vision Health Services Research Program at Queen's University, in partnership with members of the Ontario Provincial Vision Task Force, has developed evidence to inform policies aimed at optimizing both access and quality across the eye care spectrum.

Safety and Tolerability of Acetazolamide in the Idiopathic Intracranial Hypertension Treatment Trial.

OBJECTIVE: To examine the tolerability and adverse events reported in the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT). METHODS: Randomized, double-masked, placebo-controlled clinical trial. Trial participants (n = 165) with mild visual loss concurrently receiving low-sodium weight-reduction diet plus the maximally tolerated dosage of acetazolamide (up to 4 g/d) or placebo for 6 months. MAIN OUTCOMES MEASURES: adverse events (AEs), assessment of clinical and laboratory findings at study visits. RESULTS: Thirty-eight of 86 participants randomized to the acetazolamide group (44.1%) tolerated the maximum allowed dosage of 4 g/d. The average time to achieve maximum study dosage in the acetazolamide group was 13 weeks (median 12 weeks; range 10-24 weeks). A total of 676 AEs (acetazolamide, n = 480; placebo, n = 196) and 9 serious AEs (acetazolamide, n = 6; placebo, n = 3) were reported. Notably, the percentages of participants reporting at least 1 AE in the nervous, gastrointestinal, metabolic, and renal organ systems were significantly higher in the acetazolamide group (P < 0.05). The odds of paresthesia (OR 9.82; 95% CI 3.87-27.82), dysgeusia (OR ∞; 95% CI 3.99-∞), vomiting and diarrhea (OR 4.11; 95% CI 1.04-23.41), nausea (OR 2.99; 95% CI 1.26-7.49) and fatigue (OR 16.48; 95% CI 2.39-702.40) were higher in the acetazolamide group than in the placebo group. CONCLUSION: Acetazolamide appears to have an acceptable safety profile at dosages up to 4 g/d in the treatment of idiopathic intracranial hypertension. The majority of participants in the Idiopathic Intracranial Hypertension Treatment Trial were able to tolerate acetazolamide above 1 g/d for 6 months.

Peripapillary choroidal neovascular membrane in a teenage boy: presenting feature of idiopathic intracranial hypertension and resolution with intravitreal bevacizumab.

Peripapillary choroidal neovascular membrane (ppCNVM) is an infrequent finding in patients with idiopathic intracranial hypertension (IIH). In the pediatric subgroup there is only a single previously reported case. We describe the use of intravitreal bevacizumab for ppCNVM in a teenage boy with IIH.

A method of evaluating helmet rotational acceleration protection using the Kingston Impact Simulator (KIS Unit).

OBJECTIVE: Helmet use is the primary form of head protection against traumatic brain injury. Although helmet designs have proven to be effective in reducing the incidence of skull fracture and major traumatic brain injury, there is little evidence that helmets protect against concussion. Linear and rotational accelerations are important mechanisms underlying concussion, yet current testing protocols do not account for rotational acceleration. Technical considerations have prevented a valid, accurate, and reproducible testing paradigm. Our objectives were to design a novel helmet-testing methodology that accurately and reliably measures rotational acceleration at injury-relevant impact forces, locations, and planes and to evaluate differences in rotational force protection in commercially available helmets. SETTING: Laboratory study. INTERVENTION: The Kingston Impact Simulator (KIS unit) was used to study 10 commercially available hockey helmets. The rotational acceleration force protection was measured in the horizontal, coronal, and sagittal planes at each of 12 predetermined impact locations. RESULTS: Mean peak unhelmeted and helmeted accelerations at all impact locations and planes ranged from 63 to 28.6 g and from 26.8 to 8.0 g, respectively. The percent reduction in rotational acceleration for all test helmets ranged from 6.4% to 84%. Statistically significant differences in rotational acceleration between manufacturers and within a helmet brand were identified. CONCLUSIONS: KIS is a novel testing methodology that identifies rotation force protection within and between hockey helmet models and manufacturers at different impact location and planes. This information may be useful in improving future helmet design and construction to provide maximal protection against the forces causing concussion.

Eye exercises for treatment of idiopathic cranial nerve VII paresis: pilot study.

BACKGROUND: To determine if fine-motor eye exercises can be used for treatment of unilateral, idiopathic cranial nerve VII paresis to improve rate of recovery. METHODS: In this prospective, randomized controlled trial, eligible patients were randomized to perform fine-motor eye exercises (n=18) or to do no exercise (n=9) for a period of four weeks. Orbicularis oculi muscle strength was measured in paretic and unaffected eyes at baseline, two weeks and four weeks using an Orbicularis Oculi Pressure Sensor. RESULTS: The average initial strength of the paretic orbicularis oculi muscle was 34±10 mm Hg compared to the unaffected muscle which was 103±17 mm Hg at baseline (n=27). By four weeks, patients who performed eye exercises improved more than those who did not (74.4 versus 47.4 mm Hg, p=0.029). While there was some loss to follow-up, 63.8% of patients performing exercises (7/11) achieved functional recovery at four weeks compared to 12.5% (1/8) of those who did not (p=0.059). Steroids and antivirals were found to have independent positive effects on improving functional outcome. CONCLUSIONS: Eye exercises have a potential role in the treatment of idiopathic cranial nerve VII paresis and warrant consideration in the management of these patients.

Exclusive cataract surgical focus among ophthalmologists: a population-based analysis.

OBJECTIVE: An important potential unintended consequence of the growth of surgical subspecialization is the narrowing of surgical practice among comprehensive ophthalmologists. We investigated trends in the narrowing of surgical practice and the exclusive provision of cataract surgery. DESIGN: Population-based, retrospective study. PARTICIPANTS: All ophthalmologists and all ophthalmologic surgical patients in Ontario from 1994 to 2016. METHODS: We linked several health care databases to evaluate the proportion of ophthalmologists who exclusively provided cataract surgery (and no other ophthalmologic surgery) and the proportion who provided other types of ophthalmologic surgical care. To further investigate surgical focus, we evaluated the proportion of surgical cases within each surgical area for each ophthalmologist. RESULTS: Between 1994 and 2016, the proportion of ophthalmologists who exclusively provided cataract surgery rose from 10.0% to 34.9% (p < 0.0001). In contrast, the proportions of ophthalmologists providing other types of subspecialized surgical care were stable over the study period. Cataract surgeons showed high degrees of focus with a median percentage of surgical cases approaching 100% in all years. Among exclusive cataract surgeons, the median annual cataract case volume increased from 138 (interquartile range: 87-214) to 529 (interquartile range: 346-643) between 1994 and 2009 (p < 0.0001) and then plateaued. CONCLUSIONS: Between 1994 and 2016, exclusive cataract surgical focus among ophthalmologists in Ontario rose dramatically from 1 in 10 to 1 in 3 surgeons. This evolution was similar among recent graduates and established ophthalmologists. Our data may have important implications for policies regarding surgeon human resources as well as residency and fellowship training programs.

Optimization of visual evoked potential (VEP) recording systems.

OBJECTIVE: To explore the influence of environmental conditions on pattern visual evoked potential (VEP) recordings. METHODS: Fourteen subjects with no known ocular pathology were recruited for the study. In an attempt to optimize the recording conditions, VEP recordings were performed in both the seated and recumbent positions. Comparisons were made between recordings using either LCD or CRT displays and recordings obtained in silence or with quiet background music. Paired recordings (in which only one variable was changed) were analyzed for changes in P100 latency, RMS noise, and variability. RESULTS: Baseline RMS noise demonstrated a significant decrease in the variability during the first 50msec accompanied by a 73% decrease in recording time for recumbent position when compared to the seated position (p<0.05). Visual evoked potentials recorded using LCD monitors demonstrated a significant increase in the P100 latency when compared to CRT recordings in the same subjects. The addition of background music did not affect the amount of RMS noise during the first 50msec of the recordings. CONCLUSION: This study demonstrates that the use of the recumbent position increases patient comfort and improves the signal to noise ratio. In contrast, the addition of background music to relax the patient did not improve the recording signal. Furthermore, the study illustrates the importance of avoiding low-contrast visual stimulation patterns obtained with LCD as they lead to higher latencies resulting in false positive recordings. These findings are important when establishing or modifying a pattern VEP recording protocol.

Association of Cataract Surgical Outcomes With Late Surgeon Career Stages: A Population-Based Cohort Study.

Importance: Evidence suggests that the quality of some aspects of care provided by physicians may decrease during their late career stage. However, to our knowledge, data regarding the association of advancing surgeon career phase with cataract surgical outcomes have been lacking. Objective: To investigate whether an increase in cataract surgical adverse events occurs during later surgeon career stages. Design, Setting, and Participants: This population-based study of 499 650 cataract operations performed in Ontario, Canada, between January 1, 2009, and December 31, 2013, investigated the association between late surgeon career stage and the risk of surgical adverse events. Linked health care databases were used to study cataract surgical complications while controlling for patient-, surgeon-, and institution-level covariates. All ophthalmologists who performed cataract surgery in Ontario within the study period were included in the analysis. Exposures: Isolated cataract surgery performed by surgeons at early, mid, and late career stages. Main Outcomes and Measures: Four serious adverse events were evaluated: dropped lens fragments, posterior capsule rupture, suspected endophthalmitis, and retinal detachment. Results: Of 416 502 participants, 244 670 (58.7%) were women, 90 429 (21.7%) were age 66 to 70 years, 111 530 (26.8%) were age 71 to 75 years, 90 809 (21.8%) were age 76 to 80 years, and 123 734 (29.7%) were 81 years or older. Late-career surgeons performed 143 108 of 499 650 cataract operations (28.6%) during the study period. Late surgeon career stage was not associated with an increased overall risk of surgical adverse events (odds ratio [OR] vs midcareer, 1.06; 95% CI, 0.85-1.32). In a sensitivity analysis with surgeon volume removed from the model, late career stage was still not associated with overall adverse surgical events (OR, 1.10; 95% CI, 0.88-1.38). Among individual complications, late surgeon career stage was associated with an increased risk of dropped lens fragment (OR, 2.30; 95% CI, 1.50-3.54) and suspected endophthalmitis (OR, 1.41; 95% CI, 1.01-1.98). These corresponded with small absolute risk differences of 0.11% (95% CI, 0.085%-0.130%) and 0.045% (95% CI, 0.028%-0.063%) for dropped lens fragment and suspected endophthalmitis, respectively. Conclusions and Relevance: These findings suggest that later-career surgeons are performing a substantial proportion of cataract operations with overall low surgical adverse event rates. Future studies might extend evaluations to the frequency of secondary surgical interventions as additional measures of surgical care quality.

Neural network and logistic regression diagnostic prediction models for giant cell arteritis: development and validation.

PURPOSE: To develop and validate neural network (NN) vs logistic regression (LR) diagnostic prediction models in patients with suspected giant cell arteritis (GCA). Design: Multicenter retrospective chart review. METHODS: An audit of consecutive patients undergoing temporal artery biopsy (TABx) for suspected GCA was conducted at 14 international medical centers. The outcome variable was biopsy-proven GCA. The predictor variables were age, gender, headache, clinical temporal artery abnormality, jaw claudication, vision loss, diplopia, erythrocyte sedimentation rate, C-reactive protein, and platelet level. The data were divided into three groups to train, validate, and test the models. The NN model with the lowest false-negative rate was chosen. Internal and external validations were performed. RESULTS: Of 1,833 patients who underwent TABx, there was complete information on 1,201 patients, 300 (25%) of whom had a positive TABx. On multivariable LR age, platelets, jaw claudication, vision loss, log C-reactive protein, log erythrocyte sedimentation rate, headache, and clinical temporal artery abnormality were statistically significant predictors of a positive TABx (P≤0.05). The area under the receiver operating characteristic curve/Hosmer-Lemeshow P for LR was 0.867 (95% CI, 0.794, 0.917)/0.119 vs NN 0.860 (95% CI, 0.786, 0.911)/0.805, with no statistically significant difference of the area under the curves (P=0.316). The misclassification rate/false-negative rate of LR was 20.6%/47.5% vs 18.1%/30.5% for NN. Missing data analysis did not change the results. CONCLUSION: Statistical models can aid in the triage of patients with suspected GCA. Misclassification remains a concern, but cutoff values for 95% and 99% sensitivities are provided (https://goo.gl/THCnuU).

Effect of prophylactic nonsteroidal antiinflammatory drugs on cystoid macular edema assessed using optical coherence tomography quantification of total macular volume after cataract surgery.

PURPOSE: To evaluate the efficacy of prophylactic administration of the topical nonsteroidal antiinflammatory drug (NSAID) ketorolac tromethamine 0.5% on acute (within 4 weeks of surgery) cystoid macular edema (CME) and total macular volume (TMV) in patients having phacoemulsification cataract surgery. SETTING: Department of Ophthalmology, Queen's University, Hotel Dieu Hospital, Kingston, Ontario, Canada. METHODS: This open-label nonmasked randomized (random number assignment) study comprised 106 eyes of 98 patients. Exclusion criteria included hypersensitivity to the NSAID drug class, aspirin/NSAID-induced asthma, and pregnancy in the third trimester. Ketorolac tromethamine 0.5% was administered starting 2 days before surgery and for 29 days after surgery for a total of 31 days. The outcome measure was macular swelling, which was quantified by the optical coherence tomography. RESULTS: At 1 month, there was a statistically significant difference in TMV between the control group (0.4420 mm3) and the ketorolac group (0.2392 mm3), with the ketorolac group having 45.8% less macular swelling (P = .009). Multiple linear regression with backward selection indicated a 44.3% (P = .013) and 46.1% (P = .030) reduction in macular swelling in the ketorolac group at 1 week and 1 month, respectively. CONCLUSION: Used prophylactically after cataract surgery, ketorolac 0.5% was efficacious in decreasing postoperative macular edema.

The effect of neutral density filters on testing in patients with strabismic amblyopia.

OBJECTIVE: To confirm if using a neutral density filter (NDF) affects eyes with strabismic amblyopia differently compared to fellow non-amblyopic eyes, and to determine if a similar effect could be observed when using a NDF during peripheral visual field testing. DESIGN: Prospective controlled case series. PARTICIPANTS: 19 subjects with strabismic amblyopia with visual acuities between 20/400 and 20/40 in their affected eyes were recruited to the study. Fellow non-amblyopic eyes served as the control group. METHODS: Visual acuity in both eyes was assessed using a projected Snellen eye chart with two NDFs (0.4 and 3.0 densities). Visual fields were assessed using a Humphrey perimeter using one NDF (0.4 density). Best corrected visual acuity and visual fields were also recorded. RESULTS: When using a 3.0 NDF, visual acuity was reduced in all eyes (p < 0.0001). When using a 0.4 NDF, visual acuity was significantly improved in eyes with strabismic amblyopia compared to unfiltered conditions (p = 0.0011). There was no significant effect by NDFs on visual field testing in eyes with strabismic amblyopia or fellow non-amblyopic eyes. CONCLUSIONS: Neutral density filters affect eyes with strabismic amblyopia differently than they do non-amblyopic eyes. A significant improvement in visual acuity of eyes with strabismic amblyopia was observed when using a 0.4 NDF compared to non-amblyopic eyes. Visual acuity was reduced in amblyopic as well as non-amblyopic eyes when viewing through a 3.0 NDF. No significant change in visual fields was observed when using a 0.4 NDF in amblyopic or non-amblyopic eyes.

Loss of Central Vision and Audiovisual Speech Perception.

Communication impairments pose a major threat to an individual's quality of life. However, the impact of visual impairments on communication is not well understood, despite the important role that vision plays in the perception of speech. Here we present 2 experiments examining the impact of discrete central scotomas on speech perception. In the first experiment, 4 patients with central vision loss due to unilateral macular holes identified utterances with conflicting auditory-visual information, while simultaneously having their eye movements recorded. Each eye was tested individually. Three participants showed similar speech perception with both the impaired eye and the unaffected eye. For 1 participant, speech perception was disrupted by the scotoma because the participant did not shift gaze to avoid obscuring the talker's mouth with the scotoma. In the second experiment, 12 undergraduate students with gaze-contingent artificial scotomas (10 visual degrees in diameter) identified sentences in background noise. These larger scotomas disrupted speech perception, but some participants overcame this by adopting a gaze strategy whereby they shifted gaze to prevent obscuring important regions of the face such as the mouth. Participants who did not spontaneously adopt an adaptive gaze strategy did not learn to do so over the course of 5 days; however, participants who began with adaptive gaze strategies became more consistent in their gaze location. These findings confirm that peripheral vision is sufficient for perception of most visual information in speech, and suggest that training in gaze strategy may be worthwhile for individuals with communication deficits due to visual impairments.