Canadian legal cases in ophthalmology: a closer look at 40 years' worth of data.

OBJECTIVE: To assess the characteristics of malpractice lawsuits against Canadian ophthalmologists and the predisposing factors leading to claims. DESIGN: Retrospective case series. METHODS: A systematic search of the 2 largest Canadian online legal databases, LexisNexis Canada and Westlaw Canada, was performed to collect cases against ophthalmologists in Canadian courts from 1977 to 2021. RESULTS: This study comprised 68 legal cases, including 52 lawsuits, 14 cases appealed once, and 2 cases appealed twice. Most cases concerned surgical procedures (46.2%), followed by misdiagnoses or lack thereof (32.7%) and nonsurgical procedures (21.2%). Half the cases (n = 26) were immediately dismissed by the judge in favour of the ophthalmologist, though among the remaining half that proceeded to trial the majority (88.5%) were won by the patients. All appeals by patients were dismissed by the judge. The median monetary value of damages awarded was $308,202. CONCLUSIONS: This study is the first to report on ophthalmology-involved medical litigation cases in Canada. Most cases were ruled in favour of the ophthalmologist, but most of those that were not immediately dismissed by the judge were ruled in favour of the plaintiff. Notably, a plurality of these cases argued for a lack of informed consent, and every case in which a lack was successfully pleaded was ruled in favour of the plaintiff, highlighting the importance of appropriate informed consent. The findings of this study give Canadian ophthalmologists insight into areas of practice that commonly lead to litigation and can aid in improving clinical practice and risk management.

EXTENSIVE ORBITAL AND PARAPHARYNGEAL EMPHYSEMA REQUIRING URGENT CANTHOTOMY AND CANTHOLYSIS AFTER PARS PLANA VITRECTOMY.

PURPOSE: The authors report the emergent management of a case of orbital and parapharyngeal emphysema causing orbital compartment syndrome and signs of peripheral neuropathy days after pars plana vitrectomy. METHODS: Case report. RESULTS: A 20-year-old woman underwent 3-port 23-gauge pars plana vitrectomy in the right eye for total retinal detachment under general anesthesia. All sclerotomies were secured with 7-0 polyglactin 910 (Vicryl; Ethicon) sutures before instillation of 15% C3F8 gas. On the third postoperative day, the patient presented with a 3-mm proptosis, near-total ophthalmoplegia, jaw protrusion, head deviation, tongue protrusion, and facial twitching. Computed tomography showed extensive subcutaneous gas in the right orbit and bilateral parapharyngeal spaces, and a tethered right optic nerve with globe tenting. A decision was made to perform urgent lateral canthotomy and cantholysis. Three hours after canthotomy and cantholysis, her neurologic signs had resolved except for intermittent tongue protrusion, which resolved thereafter. At postoperative Week 7, the patient's vision was 20/70 and her intraocular pressure was 13 mmHg. CONCLUSION: To the authors' knowledge, this is the only report of a modern small-gauge vitrectomy procedure being complicated by orbital compartment syndrome and extensive emphysema causing peripheral neuropathy, and successfully treated with urgent canthotomy and cantholysis.

Imaging Biomarkers and Their Impact on Therapeutic Decision-Making in the Management of Neovascular Age-Related Macular Degeneration.

These recommendations, produced by a group of Canadian retina experts, have been developed to assist both retina specialists and general ophthalmologists in the management of vision-threatening neovascular age-related macular degeneration (nAMD). The recommendations are based on published evidence as well as collective experience and expertise in routine clinical practice. We provide an update on practice principles for optimal patient care, focusing on identified imaging biomarkers, in particular retinal fluid, as well as current and emerging therapeutic approaches. Algorithms for delivering high-quality care and improving long-term patient outcomes are provided, with an emphasis on timely and appropriate treatment to preserve and maintain vision. In the context of nAMD, increasing macular fluid or leakage on fluorescein angiography (FA) may indicate disease activity regardless of its location. Early elimination of intraretinal fluid (IRF) is of particular relevance as it is a prognostic indicator of worse visual outcomes. Robust referral pathways for second opinion and peer-to-peer consultations must be in place for cases not responding to intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy.

EPSTEIN-BARR VIRUS ACUTE RETINAL NECROSIS IN AN IMMUNOCOMPETENT HOST.

PURPOSE: To describe a case of Epstein-Barr virus (EBV)-associated acute retinal necrosis (ARN) in an immunocompetent patient and to summarize the clinical features of published molecularly confirmed EBV-ARN cases. METHODS: Case report and literature review. RESULTS: An 83-year-old immunocompetent woman with unilateral ARN presented with visual acuity of light perception. Oral valacyclovir was started. One week later, vitrectomy was conducted for worsening inflammation. Intraoperatively, a severe confluent necrotizing retinitis and occlusive vasculitis involving all four quadrants of posterior and peripheral retina were noted. Vitreous polymerase chain reaction was exclusively positive for EBV. Other autoimmune, infective, and hematological work-up was negative. The retinitis resolved 3 months later, but with significant macular and generalized retinal atrophy, visual acuity remained light perception. From the literature, there are four EBV-ARN cases (six eyes) diagnosed based on polymerase chain reaction or fluorescence in-situ hybridization of vitreous or retinal samples. All patients were immunocompromised or on immunosuppressive treatment. Presenting visual acuity was light perception or worse in 3/6 eyes. Three patients received systemic acyclovir-based therapy. Vitrectomy was performed in 4/6 eyes between 4 and 8 weeks from disease onset. All cases had involvement of the posterior and peripheral retina. Retinal detachment occurred in 2/6 eyes, and final visual acuity was no light perception in 3/6 eyes. CONCLUSION: This case expands the clinical spectrum of EBV-ARN to include infection in immunocompetent hosts. Epstein-Barr virus-ARN seems to be characterized by a global peripheral and posterior fulminant retinitis, with adverse visual acuity outcomes despite systemic acyclovir-based therapy. The benefits of adjunctive intravitreal foscarnet, systemic steroids, and early vitrectomy may warrant further investigation.

Impact of surgical case order on epiretinal membrane peeling surgery.

OBJECTIVE: To determine whether surgical warm-up affects epiretinal membrane (ERM) peeling complication rates and surgical case times. SETTING: Jewish General Hospital, Montreal, QC, Canada. DESIGN: Retrospective case-control study. METHODS: We assessed consecutive patients who underwent pars plana vitrectomy for ERM peel (macular pucker) by one surgeon at the Jewish General Hospital from January 2006 until March 2016. Cases evaluated were sequential ERM peels performed as the first 2 surgeries of the day. The first case of the day was considered the "warm-up" and the second case was the "post-warm-up." Baseline demographics, pre-operative characteristics, perioperative and postoperative best-corrected visual acuity (BCVA) at 2 months and 6 months, as well as postoperative complications are described. Results were analyzed using the χ2 test, t test, and Fischer's exact test. Regression models were used to identify any predictors of postoperative BCVA. RESULTS: The study reviewed 108 patients. The warm-up group was compared with the post-warm-up group, and there was no significant difference between the mean pre-operative BCVA and the post-operative BCVA at 2 and 6 months. ERM peeling surgery complication rates were not statistically different between the warm-up cases and the post-warm-up cases. There was a tendency for performing complex surgeries that needed phaco procedures in post-warm-up cases (13% vs 2%, p = 0.03). Analysis of simple ERM peeling procedures (with no concomitant phaco procedures) showed no statistically significant tendencies for any of the groups to go beyond the 60 minutes allocated for the surgery (25.4% vs 20.0%, p = 0.27). CONCLUSION: Warming-up does not influence the rate of postoperative complications or the postoperative BCVA in patients undergoing ERM peels. The strongest predictor of post-operative BCVA was pre-operative BCVA.

Disorganization of Retinal Inner Layers and Ellipsoid Zone Disruption Predict Visual Outcomes in Central Retinal Vein Occlusion.

PURPOSE: To assess the associations and predictive value of spectral-domain (SD) OCT inner and outer retinal structural parameters and visual acuity (VA) outcomes in macular edema (ME) secondary to central retinal vein occlusion (CRVO). DESIGN: Retrospective, longitudinal cohort study. PARTICIPANTS: Eighty-four patients with ME secondary to CRVO receiving pro re nata anti-vascular endothelial growth factor (VEGF) therapy at 3 tertiary-level retina referral centers. METHODS: In all participants, VA, demographic and clinical parameters, and SD OCT images from baseline, 3 months, and 12 months were reviewed. Spectral-domain OCT-based morphologic features in the 1500-µm foveal zone were analyzed by masked graders for disorganization of the retinal inner layers (DRIL), ellipsoid zone (EZ) and external limiting membrane disruption, cone outer segment tip (COST) visibility, cysts, subretinal and intraretinal fluid, and epiretinal membranes. MAIN OUTCOME MEASURES: Spectral-domain OCT-based retinal structural parameters and VA outcomes. RESULTS: In multivariate analyses adjusting for baseline VA, worsening VA over 1 year was associated with 1-year increases in DRIL (point estimate, 0.06 per 100 µm; P < 0.001) and EZ disruption (0.07 per 100 µm; P = 0.023), but decreased COST visibility (-0.09 per 100 µm; P = 0.018). A 3-month increase in DRIL (0.05 per 100 µm; P = 0.003) and EZ disruption (0.10 per 100 µm; P < 0.001) were the only factors predicting VA worsening over 1 year, after controlling for baseline VA. A multivariate model including 3-month evolution in DRIL, EZ disruption, and VA accounted for 86.3% of variability in 1-year VA change. Absolute differences between predicted and actual 1-year VA were within 2 lines in 80.9%. When DRIL increased by 250 µm or more over 3 months, no eyes showed VA improvement of 1 line or more in 1 year. When EZ disruption decreased by 250 µm or more over 3 months, no eyes worsened by 1 line or more over 1 year. CONCLUSIONS: Early recovery over 3 months in both DRIL and EZ parameters are key drivers of 1-year VA outcomes. Predictive models incorporating 3-month changes in DRIL and EZ disruption support their usefulness as potential robust determinants of future VA.

Ocriplasmin versus vitrectomy for the treatment of macular holes.

OBJECTIVE: To compare the anatomical and visual outcomes of patients with bilateral macular holes (MH) who have been treated with pars plana vitrectomy in one eye and intravitreal ocriplasmin in the fellow eye. DESIGN: Multicentre, retrospective case series. PARTICIPANTS: Twenty-two eyes of 11 patients with bilateral MH treated with vitrectomy in one eye and ocriplasmin in the other were included. Patients were followed-up by 5 vitreoretinal surgeons from 3 retinal practices in Canada. METHODS: All charts were reviewed for data collection, and optical coherence tomography (OCT) scans pre- and posttreatment were evaluated. RESULTS: MH closed primarily in 36.4% (n = 4) of the ocriplasmin-treated eyes and in 90.9% (n = 10) of the vitrectomy-treated eyes (p = 0.031). The 4 successfully treated ocriplasmin MH were preceded by a vitreomacular traction (VMT) release. Three additional ocriplasmin-treated eyes achieved a VMT release without MH closure. All persistent MH (100%) closed with subsequent vitrectomy, with no significant difference in final best-corrected visual acuity (BCVA) between those who achieved MH closure with primary or secondary interventions (p = 0.073). Final BCVA improved from logMAR 0.85 ± 0.34 to 0.37 ± 0.22 (p = 0.005) in the vitrectomy eyes and from 0.56 ± 0.28 to 0.28 ± 0.16 (p = 0.009) in the ocriplasmin eyes, with no significant difference in final BCVA between treatments (p = 0.306). Postoperative ellipsoid zone disruption persisted more frequently in vitrectomy-treated eyes. CONCLUSION: Both procedures were associated with improved visual outcomes, but eyes initially treated with vitrectomy had a higher primary MH closure rate. On OCT, patients had more outer structural changes in vitrectomy eyes than in ocriplasmin eyes.

Long-term outcomes of sutureless 25-G+ pars-plana vitrectomy for the management of diabetic tractional retinal detachment.

PURPOSE: To evaluate the short- and long-term surgical and clinical outcomes in eyes with diabetic tractional retinal detachment (TRD) undergoing 25-G+ pars-plana vitrectomy (PPV). METHODS: A total of 238 patients were reviewed for inclusion in this study. A retrospective cohort study of 109 eyes of 73 patients operated on for diabetic TRD were included. All eyes received intraocular tamponade of air, sulfur hexafluoride, octofluropropane or silicone oil. All patients were followed up for a minimum period of one year. RESULTS: The mean age of all patients at surgery was 53.9 years ± 9.2, while the mean duration of diabetes was 18.7 ± 10.4 years. The mean length of follow-up was 923 ± 87 days after surgery (range, 432-1792 days). Thirty-two cases (29.3 %) had an associated rhegmatogenous component. Mean BCVA improved from logarithm minimum angle of resolution (logMAR) 1.17 (20/300) to 0.812 (20/130) (p < 0.05). All eyes underwent intraoperative laser photocoagulation. Primary, single-surgery anatomic reattachment was achieved in 99 eyes (91 %). Final anatomic attachment was achieved in 107 eyes (98 %). There was no statistically significant difference in primary or secondary re-attachment rate in terms of type of tamponade agent used. There were five cases of post-operative hypotony (≤5 mmHg) on postoperative day 1, while 11 eyes had IOP ≥ 30 mmHg. There were no cases of endophthalmitis in our cohort. CONCLUSIONS: 25G+ PPV provides for safe and effective repair of diabetic TRDs. Patients experienced positive functional and anatomic outcomes, with no significant intraoperative complications and minimal postoperative sequelae.

Usefulness of Discarded Vitreous Samples from Routine Vitrectomy.

Purpose. To describe the histopathological features of vitreous samples obtained after vitrectomy surgery from diabetic and nondiabetic patients. Methods. Vitreous specimens from 137 patients who underwent vitrectomy for different clinical conditions were analysed. All samples were centrifuged and each resulting pellet was fixed and processed as part of routine paraffin section histopathology. The histopathological features were categorized in a semiquantitative fashion. The samples from diabetic and nondiabetic patients were compared. Results. The 125 included patients (58 diabetic, 60% males) were aged 64.2 ± 13.9 years. The presence of hemorrhage, inflammatory cells, and histiocytes was significantly higher in the diabetic group (P < 0.001, P = 0.028, and P = 0.016, resp.), showing more vessels (P < 0.001) and ghost vessels (P = 0.049). The presence of inflammatory cells was the feature with the highest sensitivity for detecting diabetes mellitus (98%) and also the highest negative predictive value (89%). In the multivariate analysis, three variables emerged as independent significant predictors of diabetes in vitrectomy samples: hemorrhage, endothelial-lined vessels, and age (P < 0.001, P < 0.001, and P = 0.019, resp.). Conclusions. Different histopathological features can be found in vitreous samples from diabetic patients. Analysis of vitrectomy samples may serve as a tool for diabetes management.

Spatial judgments in patients with retinitis pigmentosa.

Previous investigations into cortical plasticity in the presence of ocular disease have focused on central retinal damage. Perceptually, patients often report distortions of visual space which can be partially explained by perceptual filling-in. The mechanisms involved could also apply to peripheral field loss. Spatial interval discrimination was tested in 28 retinitis pigmentosa (RP) patients and a control group. When stimuli were presented to both hemispheres, bias did not differ whereas threshold was poorer in RP patients. When presenting the task to only one hemifield, bias was related to field asymmetry, but only in the left visual field, r(2)=.59. Brain laterality may be an important factor when examining changes in cortical function in response to peripheral system damage.

Management of optic disk pit-associated macular detachment with tisseel fibrin sealant.

BACKGROUND: Optic disk pit-associated macular detachment is a challenging condition to treat. Many surgical methods have been used to treat this condition with varying degrees of success. METHODS: We managed optic disk pit-associated macular detachment in three cases with pars plana vitrectomy, fluid-air exchange, drainage of subretinal fluid through the optic disk pit, application of Tisseel fibrin sealant (Baxter Healthcare Corporation, CA) to the optic disk pit, C3F8 gas injection, and postoperative prone positioning. RESULTS: All three patients maintained flat maculae and had improved vision. Patient 3 had postoperative macular hole formation. This was managed successfully with pars plana vitrectomy, internal limiting membrane peeling, fluid-air exchange, and C3F8 gas injection. CONCLUSION: Our case series suggest that Tisseel fibrin sealant in conjunction with pars plana vitrectomy can be used successfully for management of optic pit disk-associated macular detachments.

Hierarchical linear modeling of visual acuity change over time: rate of functional recovery after macular hole surgery.

PURPOSE: To examine acuity recovery rate after Macular Hole (MH) surgery, using Hierarchical Linear Modeling (HLM) with linear and curvilinear regression analysis. METHODS: Preoperative MH diameter (OCT) and acuity (ETDRS) were recorded in 20 eyes. Acuities were tested during follow-up (6 to 23 months), with three to eight measurements per eye. The resulting 95 acuities were analyzed using HLM. Variability at the level of the person was explained by change over time, using a natural logarithm conversion. Across patients, MH diameter was used to predict slopes and intercepts at the level of the individual. RESULTS: MH diameter was able to account for significant amounts of variability in preoperative acuity (intercept) and significantly influenced rate of functional recovery (slope). A nonlinear approach to the data accounted for the largest amount of variance. CONCLUSIONS: Participants with larger MHs recovered relatively more acuity sooner while eyes with smaller MHs had better absolute acuity outcome. HLM provides important insight into the recovery process after MH surgery and is more flexible with follow-up data. In the context of MH treatment, most recuperation occurred during the initial 6 months.

Preoperative B-scan ultrasonography of the vitreoretinal interface in phakic patients undergoing rhegmatogenous retinal detachment repair and its prognostic significance.

PURPOSE: To perform ultrasonographic evaluation of the preoperative status of the posterior vitreoretinal interface in phakic patients undergoing surgery for retinal detachment (RD) with flap tear(s) and to investigate its relationship with postoperative anatomic and visual acuity outcomes. METHODS: A prospective, consecutive case series including 50 phakic eyes of 49 patients with retinal detachment and flap tear(s) undergoing retinal detachment surgery by a single vitreoretinal surgeon, who was unaware of the patient's preoperative B-scan ultrasonographic findings. Main outcome measures were comparisons between patients with partial versus complete posterior vitreous detachment (PVD) of primary retinal reattachment rates (retinal reattachment with a single surgical procedure), rates of retinal reattachment at month 12, and visual acuity outcomes at month 12. RESULTS: Partial PVD was observed in 22 (44%) eyes and complete PVD in 28 (56%) eyes. Eighteen eyes underwent pneumatic retinopexy, 15 underwent scleral buckling, and 17 underwent pars plana vitrectomy. Retinal reattachment with a single surgical procedure was achieved in 76% (38/50) of eyes, including 54.5% (12/22) of eyes with partial PVD at baseline and 92.9% (26/28) of eyes with complete PVD at baseline (P < 0.01). Stratification by type of surgical intervention demonstrated a significantly higher rate of primary anatomic success for pneumatic retinopexy among patients with complete PVD compared to partial PVD (P = 0.02). Retinal reattachment at month 12 was achieved in 100% (50/50) of eyes. At last follow-up, the mean (+/-SD) number of interventions was 1.70 (+/-1.10) for patients with partial PVD at baseline and 1.10 (+/-0.30) for patients with complete PVD (P < 0.01). There was no significant difference among the groups in mean change in visual acuity from baseline to month 12, nor in the distribution of visual acuities at month 12. CONCLUSIONS: In phakic patients with retinal detachment and flap tear(s), a higher primary anatomic success rate may be associated with the presence of a complete PVD compared to a partial PVD. Subgroup analysis suggests that the presence of partial PVD at baseline might influence negatively the primary anatomic success rate, particularly for eyes undergoing pneumatic retinopexy.

Differences between recognition and resolution acuity in patients undergoing macular hole surgery.

PURPOSE: The present investigation compared recognition acuities (ETDRS chart) with resolution acuities (Landolt-C chart) in a sample of patients with idiopathic macular holes (MH). Traditionally, visual acuity in a clinical setting is measured with a letter chart. Yet, the ability to recognize a letter differs from a resolution task, such as detecting the direction of a gap in a ring. It was hypothesized that resolution acuity would be more impaired than recognition acuity in patients with MH, because component cues in letter optotypes are not available in Landolt-Cs. METHOD: Visual acuities of 23 patients with MH (age range, 52-82) were tested, using standard ETDRS and Landolt-C charts. Optical coherence tomography was used to confirm the diagnosis of MH. RESULTS: Acuities correlated strongly, before and after surgery (r = 0.92 and r = 0.95, respectively). However, paired t-tests determined that resolution acuity was significantly more impaired at both time points than was recognition acuity (P < 0.001). Using Bland-Altman plots, the limits of agreement between the two acuity types indicated that resolution acuity differed from recognition acuity by up to five lines before surgery and up to 3 lines after surgery. CONCLUSIONS: ETDRS and Landolt-C acuities differ in a clinically significant way in patients before and after MH surgery. Measuring recognition acuity by reading letters may lead to an overestimate of visual ability at the retinal level in patients with MH by including compensatory top-down cognitive processes that are unavailable for resolution tasks.

Macular hole: perceptual filling-in across central scotomas.

The present study examined perceptual distortions of a vertical line before and after macular hole (MH) surgery in 25 eyes of 24 patients. Participants' perceptual reports of distortions were classified as solid, bent right/left, thinned at the center, or broken. The majority of patients (72%) reported symmetrical distortions of the line pre-operatively. After surgery, participants with larger MHs were more likely to retain residual distortions. Of particular interest is the group reporting thinning of the line preoperatively, as the center should be perceptually missing. Examination of MH diameters in relation to the line perceptions indicated that the shape of the perceived line can be explained at the retinal level, while its continuity must be perceptually created at the cortical level.

Visual function assessment and metamorphopsia after macular hole surgery.

The purpose of this study was to develop a new resolution acuity measure for patients after macular hole surgery. Fifty eyes of 44 patients who had undergone successful treatment were tested. Visual acuity was measured with the Snellen, Early Treatment of Diabetic Retinopathy Study and Landolt-C charts. A Line Resolution Test was performed as part of their follow-up exam where a vertical line was presented. Participants were categorized by their perception of the line as solid, bent or broken. The line could be distorted into a sine-wave pattern in order to determine the participants' detection threshold for the distortion. Chart acuities did not differ among the three groups, as categorized by their line perception. Only the distortion measure was sensitive enough to differentiate the solid- from the broken-line group. The distortion measure assesses resolution power of the macula in smaller increments than acuity charts. This hyperacuity approach is more appropriate in the assessment of functional outcome after microsurgery.

Internal limiting membrane: ultrastructural relationships, with clinical implications for macular hole healing.

BACKGROUND: Recent data on macular hole formation have changed our understanding of the mechanisms involved. However, the mechanisms of macular hole closure, despite the introduction of internal limiting membrane (ILM) removal, are not fully understood. We reviewed the charts of patients who underwent surgery for macular hole with and without intentional removal of ILM and reviewed the basic science literature on the components and relationships of the ILM-glial cell interface to help interpret our surgical data. METHODS: We reviewed the records of 205 eyes with a clinical diagnosis of macular hole at a university centre in Montreal between 1998 and 2002. Of these, 117 eyes of 108 patients were included. Vitrectomy with intentional ILM removal was done under indocyanine green (ICG) staining. Macular hole stage and rates of hole closure, failure and reopening were recorded, comparing the eyes with intentional ILM peeling versus no ILM peeling. Anatomic success was defined as a flat/closed configuration. A basic science literature review was done through the PubMed search engine with the key words "internal limiting membrane," "internal limiting lamina," "macular hole," "retinal glial cells" and "retinal Müller cells." RESULTS: Eighty-four eyes had ICG-guided ILM removal (26 stage 2 macular holes, 45 stage 3 holes and 13 stage 4 holes), and 33 eyes had no ILM removal (10 stage 2 holes and 23 stage 3 holes). Of the 117 eyes 110 (94.0%) were successfully closed. Four (3.6%) of the closed holes reopened (none had ILM peeling), and 7 (6.0%) of the 117 eyes had primary failure. Ten of the 11 eyes that had primary failure or hole reopening were reoperated, and 8 were successfully closed after the second procedure. One patient refused reoperation. Including second procedures, the final anatomic closure rate was 97.4% (114/117). INTERPRETATION: Intentional ILM peeling is not mandatory for all macular holes to close but does play a role in preventing reopening. Removal of ILM increases the rate of flat/closed hole configuration on reoperation without the need for biologic adjuvants. Review of the basic science evidence helped clarify the possible role of ILM removal.