Annual Visual Sciences & Ophthalmology Research Day

Purpose
To evaluate the long-term effectiveness of corneal collagen cross-linking (CXL) in stabilizing corneal topographic indices and visual outcomes in patients with corneal ectasia.

Methods
A retrospective chart review was conducted on 75 eyes of patients with corneal ectasia who underwent corneal cross-linking at a private ophthalmology clinic in Canada between 2018 and 2024. Timepoints included a pre-operative visit, and post-operative follow ups at 3 months, 1-year, and 2-years. Primary outcomes included autorefraction, visual acuity, and corneal topography indices. The secondary outcomes extracted were complication rates such as delayed epithelial healing, repeat CXL or corneal transplantation, and subepithelial fibrosis.

Results
At baseline, the mean spherical equivalent (SE) was –5.25 ± 4.71 D. At 1 year, SE improved modestly to –4.69 ± 3.23 D (p = 0.45), and at 2 years improved significantly to –1.20 ± 14.33 D (p = 0.024). No statistically significant changes were observed in refractive cylinder or Kmax, although Kmax trended toward flattening. Visual acuity, central corneal thickness and epithelial thickness measures remained stable across timepoints. Complication rates were low: delayed or limited epithelial healing occurred in 10% of eyes (n=8), while repeat CXL was performed in only 1% (n=1). No eyes underwent corneal transplantation following cross-linking during the study period.

Conclusions
CXL was highly effective in stabilizing corneal topography and refractive outcomes in patients with corneal ectasia in our cohort. While visual acuity and astigmatism remained stable, a significant improvement in spherical equivalent was observed at 2 years. Complication rates were low, supporting the safety and efficacy of CXL in routine clinical practice.

Effectiveness of Corneal Cross-Linking in Stabilizing Corneal Topography and Visual Outcomes in Corneal Ectasia

 

Purpose
As demand for cataract surgery grows, rural populations in geographically vast regions like Alberta face significant access barriers. This retrospective, observational quality improvement study examines cataract surgery access for rural Albertans through a sustainability lens to guide future policy and resource planning.

Methods
Patient location (city/town and postal code) was analyzed for individuals who underwent cataract surgery between June 1, 2024, and January 30, 2025, at the Holy Cross Surgical Center in Calgary (272 patients, 450 eyes) and the Chinook Regional Hospital in Lethbridge (296 patients, 517 eyes). Surgical complexity and premium intraocular lens (IOL) selection were recorded. CO₂ emissions from travel were estimated using the myclimate calculator, assuming personal petrol car use (8.6L/100km).

Results
Patients traveled significantly farther to Calgary (mean 84.1km round trip; n = 450 procedures) than to Lethbridge (mean 72.6km; n = 517; Mann-Whitney test, p<0.0001). Travel distance did not vary by surgical complexity. Patients traveling >200km to Calgary (n = 58) were more likely to select premium IOLs compared to local patients (n = 393; Fisher’s exact test, p = 0.03), suggesting potential economic disparity in access. Universal implementation of immediately sequential bilateral cataract surgery (ISBCS) could reduce CO₂ emissions by 43.2% (~16.7 tons/year); a 36.1% opt-in rate would still achieve a 16.5% reduction (~6.15 tons/year).

Conclusion
Expanding ISBCS could significantly reduce environmental impact while improving equitable access to cataract surgery for rural populations. Continued analysis will inform evidence-based strategies for sustainable, patient-centered surgical care in Southern Alberta.

 

Why Stop at One When You Can Do Both?

 

Purpose
Understanding how brain activity decodes into visual perception and behaviour is a fundamental challenge in vision science, requiring tools that precisely measure when neuronal circuits are most critical. We developed a new approach that, for the first time, reveals the millisecond-by-millisecond relationship between visual system activity and behaviour, uncovering the dynamics of visual processing and informing the development of next-generation visual prosthetics for visual restoration and augmentation.

Methods
We used a novel “white noise” optogenetic stimulation method, delivering brief (25 ms), ultra-weak (microwatt) and randomly timed light pulses to the primary visual cortex (V1) or superior colliculus (SC) in mice performing a visual detection task. By aligning these pulses with behavioural outcomes, we generated high-resolution neuronal-behavioural kernels (NBKs) that pinpoint when perturbations in visual system activity influence perception and decision-making. An innovative framework combining machine learning algorithms and a powerful statistical analysis (Bayesian Inference) dynamically detected critical time periods of neuronal activity related to visually-guided behaviour.

Results
Our approach uncovered distinct temporal windows when V1 and SC activity most strongly influenced visual detection performance. Our statistical framework successfully tracked these dynamic effects even with behavioural variability, providing a powerful and flexible tool for studying how visual circuits shape perception.

Conclusion
This first-of-its-kind method allows unprecedented insight into the rapid and complex dynamics of visual perception and decision-making. Beyond advancing vision science, our work sets the stage for informing the future neurotechnologies to restore and augment vision by identifying when and how neuronal signals drive visual perception.

Mapping the Temporal Dynamics of Visual Perception

Purpose
Uveal melanoma (UM) is a rare but deadly eye cancer with a 15-year mortality rate of 45%. Early detection is essential to improving outcomes, making timely referrals to specialists critical. The objective was to characterize the perspectives of various stakeholders involved in the referral process for suspected UM.

Methods
Using a cross-sectional mixed-method design, three stakeholders – ocular oncologists, primary eye care providers (optometrists and ophthalmologists), and patients from across North America – were surveyed and/or interviewed.

Results
Fifty-one stakeholders participated. Among 21 primary eye care providers, three felt “very confident” in differentiating between low- and high-risk lesions. Many were uncertain about where to send referrals and noted a shortage of ocular oncologists.
Eighteen ocular oncologists reported that 38% of UM cases are referred later than ideal, with 22% showing poor prognosis among initial evaluation. They also indicated that inadequate referral information led to difficulties triaging patients.
Twelve patients highlighted issues such as delayed diagnosis, and extensive travel and eye care costs.

Conclusions
The referral process for suspected uveal melanoma is complicated and obscure. The results of this study could help inform future interventions aimed at improving that process for all stakeholders.

 

Challenges and Stakeholder Perspectives in the Referral Process for Suspected Uveal Melanoma

 

Purpose
Genetic conditions such as Leber Congenital Amaurosis disrupt retinal development and cause permanent blindness. In the embryonic retina, neurogenesis is regulated by protein signaling, but ceases in postnatal mammals. The zebrafish retina produces neurons through life partially via Müller glia (MG). Zebrafish MG produce rod precursors; and after injury, reprogram to replace lost retinal cells. MG in the mammalian retina are not neurogenic. The signaling mechanisms that regulate the neurogenic capacity of MG in the zebrafish retina are misunderstood. Here, we investigate how the signaling protein Semaphorin3fa (Sema3fa) limits MG proliferation in the healthy and injured zebrafish retina

Methods
We use a light injury model to ablate larval zebrafish photoreceptors. We use fluorescent in situ hybridization to visualize gene expression, and RT-qPCR to quantify gene expression. We use a CRISPR/Cas9 generated loss of-of-function mutant for Sema3fa to assess its function and EdU to measure proliferation.

Results
In the larval zebrafish retina sema3fa is expressed in and around MG. Sema3fa receptors are expressed in select MG, indicating that specific MG can respond to Sema3fa. We see increased proliferation (EdU+ cells) in the resting and injured Sema3fa loss-of-function retina. Through RT-qPCR, we see increased expression of proliferative genes in healthy and injured mutants.

Conclusion
Our results suggest that Sema3fa inhibits MG proliferation in the zebrafish retina. The findings from this project will help identify ways to remove brakes in endogenous stem cell pathways in the human retina that need to be therapeutically re-awakened to replace cells lost in childhood retinal diseases.

Semaphorin3fa as a Proliferative Brake in the Zebrafish Retina

Background
The integration of diagnostic image analysis using artificial intelligence (AI) into clinical ophthalmology practices is advancing rapidly, promising significant improvements in diagnostic accuracy, workflow efficiency, and patient outcomes. However, the clinical implementation of these technologies varies considerably. The purpose of this study is to evaluate currently available AI-based ophthalmic software to inform practitioners about their potential for integration into routine clinical care.

Methods
This study employed a rapid review design. Searches were conducted using Crunchbase, Pitchbook, advanced Google search, and ChatGPT-based web searches. Technologies were included if they were commercially available; specifically applied to ophthalmology; and used diagnostic images. Relevant websites and supporting documentation were reviewed. The following information was systematically extracted: primary eye disorder, regulatory approval status, intended use, clinical value proposition, implementation requirements, and revenue model.

Results
Complete results of are summarized in table 1. Ten companies were identified, 90% of which were developed to identify diabetic retinopathy. Of these, 60% of which were approved by the Food & Drug Administration in the United States and 70% were approved by the Conformité Européenne representing approval within the European Union but only 30% of the companies were approved for diagnosis (vs decision support) – representing a higher threshold of clinical accuracy for regulatory approval.

Conclusion
This study demonstrates that AI-driven ophthalmic solutions are primarily focused on diabetic retinopathy. The majority of these have been approved for decision support, which may limit their value to ophthalmology clinics, where experience in diagnosing this condition is already prolific.

Evaluating AI Diagnostic Software for Ophthalmic Clinical Practice

Introduction
Proliferative vitreoretinopathy (PVR) is a leading cause of recurrent retinal detachment (RD) following surgical repair, driven by inflammatory and fibrotic processes on the retinal surface. Methotrexate (MTX), a folate antagonist with antiproliferative and anti-inflammatory properties, has emerged as a potential adjunctive therapy in PVR management. This study evaluates clinical outcomes, complications, and predictors of RD recurrence following intravitreal MTX in a Canadian cohort.Introduction: Proliferative vitreoretinopathy (PVR) is a leading cause of recurrent retinal detachment (RD) following surgical repair, driven by inflammatory and fibrotic processes on the retinal surface. Methotrexate (MTX), a folate antagonist with antiproliferative and anti-inflammatory properties, has emerged as a potential adjunctive therapy in PVR management. This study evaluates clinical outcomes, complications, and predictors of RD recurrence following intravitreal MTX in a Canadian cohort.

Methods
A retrospective chart review was conducted on 35 eyes from 35 patients who received intravitreal MTX (200-400μg/0.05-0.1mL weekly for up to 12 weeks) following pars plana vitrectomy for RD associated with, or at high risk of developing, PVR. Primary outcomes were best-corrected visual acuity (BCVA), RD recurrence, and complications. Secondary analyses assessed correlations between baseline clinical characteristics and final BCVA.

Results
Of the cohort, 22 patients (62.8%) had confirmed PVR-C, while 13 (37.1%) had milder forms of PVR and received MTX prophylactically. The median follow-up was 182 days. Recurrent RD occurred in 6 patients (17.1%). BCVA improved significantly from baseline at both 6 and 12 months (p<0.001).  Baseline BCVA moderately correlated with final BCVA (ρ=0.45, p=0.010). Anterior chamber inflammation also decreased significantly over time (p<0.001). The most common complications were elevated intraocular pressure (62.9%), transient hypotony (51.4%), epiretinal membrane formation (51.4%), and corneal abrasions (25.7%).

Conclusion

Intravitreal MTX appears to be a safe adjunctive therapy that may enhance visual outcomes and reduce RD recurrence in high-risk patients with or without established PVR. Further prospective studies are warranted to refine dosing protocols and confirm long-term efficacy.

 

Movement Impairments Do Not Preclude Visuomotor Adaptation After Stroke

 

Purpose
Attention efficiently allocates our limited cognitive resources by prioritizing specific sensory inputs for further processing to enhance performance and speed reaction times. These behavioural changes are coupled to concurrent changes in neurophysiological processes such as enhanced responses of visual neurons, reduced influence of distracting information, and increased arousal. While these processes covary, emerging literature shows that they arise from distinct neurobiological processes. Given this, parsing the diverse neural mechanisms that support attention is critical for developing new diagnostic tools and therapeutics for attention-related disorders, ultimately improving mental health outcomes.

Methods & Results
To address, we will analyze a rich dataset of 2,525 neurons recorded in visual area V4 of two macaque monkeys while they performed a challenging visual attention task. Attention was manipulated to engage either selective or distributed attentional mechanisms, allowing us to examine interactions between attentional states, arousal, neuronal spiking, and task performance. Machine learning techniques, including Tensor Decomposition, ISOMAP, and projections onto experimenter-defined subspaces, were employed to identify low-dimensional signatures linked to attentional states.

Conclusion
By parsing how shifting between selective and distributed attention impacts neurophysiological and behavioural correlates of attention in neuronal populations and linking these low-dimensional signatures to spiking activity in visual neurons, we aim to refine our understanding of fundamental cognitive functions.

Parsing the Electrophysiological Signatures of Attention

 

Purpose
Stroke survivors commonly engage in rehabilitation to reduce movement impairments. Visual feedback is often used by therapists to support the relearning of movements essential for daily activities. Our work has shown that strokes can disrupt the processes that support visuomotor learning in early recovery, but how these impairments evolve over the first six months remains unclear. Here, we examined impairments in visuomotor adaptation during the first six months of recovery.

Methods
Participants with first-time, unilateral stroke completed a robotic visuomotor adaptation task at four timepoints (<3-, 6-, 12-, 26-weeks post-stroke). A 30° rotation altered the relationship between the motion of the participant’s occluded arm and a hand feedback cursor displayed in their workspace. We measured the rate and amount each participant adapted to this disturbance. Normative thresholds from healthy controls, matched for overall age and sex, were used to identify impairments (performance <5th percentile).

Results
We assessed 133 controls and stroke survivors (n = 46, 24, 23, 17) across four post-stroke timepoints. At <3 weeks post-stroke, 50% of participants were impaired in visuomotor adaptation. The incidence of impairment decreased over time, with 76.5% of participants unimpaired by 26 weeks. Late adaptation impairments persisted in 17.6% of participants at 26 weeks.

Conclusion
Impairments in visuomotor adaptation are common early after stroke and persist in a subset of individuals through the first six months of recovery. Early identification of these deficits may help clinicians target impairments directly or select alternative approaches, such as explicit task instruction, to improve adaptive motor learning.

 

Impairments in Visuomotor Adaptation in the First Six Months of Stroke Recovery

 

Background
X-linked agammaglobulinemia (XLA) is a rare primary immunodeficiency characterized by absent B cells and severely reduced immunoglobulin levels. Corneal scarring is an uncommon but vision-threatening complication of recurrent conjunctivitis in XLA.

Clinical Case
An 11-year-old boy with genetically confirmed XLA, maintained on regular IVIG therapy (IgG trough levels >9 g/L), presented with a 9-month history of recurrent conjunctival injection and mucopurulent discharge. Conjunctival swabs isolated Haemophilus influenzae sensitive to amoxicillin on two separate occasions. Initial management with antihistamines and topical ointments provided temporary relief. Nasolacrimal duct probing was performed but failed to resolve symptoms. A prophylactic regimen of systemic amoxicillin (250 mg twice daily) was initiated, resulting in significant reduction of conjunctivitis episodes. After three years of stable control, prophylaxis was discontinued by the patient’s family due to concerns about long-term antibiotic use. This led to the recurrence of severe bilateral conjunctivitis with green discharge, photophobia, and ocular pain. Examination revealed bilateral corneal scarring with reduced visual acuity (20/25 right eye, 20/40 left eye). Resumption of amoxicillin improved symptoms, but corneal scarring and visual impairment persisted.

Conclusion
This case highlights that IVIG therapy, while effective for preventing systemic infections in XLA, may not protect against conjunctivitis because of underlying Bruton’s tyrosine kinase dysfunction or impaired ocular immune homeostasis. Sustained prophylactic antibiotics can prevent recurrent conjunctivitis and its complications, including the rare but vision-threatening development of corneal scarring. Given this risk, patients with XLA require regular ophthalmologic monitoring, early antibiotic intervention, and long-term treatment adherence within a multidisciplinary care framework.

 

Recurrent Haemophilus Influenzae Conjunctivitis and Corneal Scarring in a Child with X-Linked Agammaglobulinemia

 

It is well known that the retina serves as a light-sensing organ, but non-mammalian vertebrates have an additional photosensitive organ. These animals have the pineal complex (PC), a light-sensitive “third eye” situated on the top of their head, that senses environmental light cues and links them to neuroendocrine processes. There are many morphological and molecular similarities between retinal and pineal photoreceptors. For instance, pineal photoreceptors exhibit the same cellular structure as rod and cone photoreceptors in species such as lamprey, fish, and amphibians. Further, both retinal and pineal photoreceptors use opsins, Transducin, and interphotoreceptor retinoid-binding proteins for phototransduction. Finally, studies suggest a common neural lineage among retinal photoreceptors and pineal photoreceptors.

In this study, I determined the organization of cells within the pineal complex and how this organization emerges over development. I utilized the experimentally accessible Xenopus laevis model, which has a pineal complex that we find expresses multiple opsins. I studied photoreceptors that express Pinopsin and/or Melanopsin, two opsins that our lab has found play key roles in circadian regulation, the former via the pineal complex and the latter involving the eye.

We used fluorescent in situ hybridization, immunohistochemistry, and advanced imaging techniques to examine melanopsin and Pinopsin expression over larval development. We determined the cellular arrangement of photoreceptors, projection neurons, and melatonin-synthesizing cells at different developmental stages. This study sheds light on our understanding of how the cellular organization of the third eye of non-mammalian vertebrates develops. This analysis also helps us to better understand the structural and functional links between the retina and the pineal complex.

Non-Visual Photoreceptor Structure in the Forgotten Third Eye

Purpose
We report a rare pediatric ocular adnexal high grade B cell lymphoma on a background of ataxia telangiectasia; an inherited neurodegenerative disorder that increases the risk of developing Non-Hodgkins Lymphoma up to 25%.

Methods
Case Report

A 12 year old male was referred to our hospital with a 1-week history of rapidly progressive left orbital swelling. His medical history was notable for ataxia telangiectasia, with secondary immunodeficiency and microcephaly.  Best corrected visual acuity measured 20/100 OS and 20/30 OD with normal intraocular pressures OU. Ophthalmic exam revealed significant left proptosis, chemosis and minimal excursion of extraocular movements in all directions. The remainder of the exam was unremarkable. Orbital biopsy was performed via a transcaruncular approach.

Histopathology identified Burkitt’s lymphoma (BL) and high grade B-cell Lymphoma as differential possibilities (Figure 2), with additional characterization via FISH revealed 40% MYC gene rearrangement clinching the diagnosis of BL. The patient underwent 4 courses of IV and intrathecal chemotherapy (Cyclophosphamide, Vincristine, Methotrexate, Cytarabine). 6 months post-presentation he is doing well, with no evidence of metabolically active lesions on PET scan.

Conclusions
Non Hodgkin’s Lymphoma of the ocular adnexa is known to present at higher frequencies in immunocompromised patients, including ataxia telangiectasia. To the best of our knowledge, this is the first case of pediatric high-grade B cell NHL in the ocular adnexa presenting with a background of ataxia telangiectasia. This case also highlights the value of additional molecular genetic testing, which ultimately excluded the diagnosis of Burkitts lymphoma.

 

High-Grade B Cell Lymphoma in a Child with Ataxia Telangiectasia

 

Purpose
There are few studies that characterize the burden of eye cancer and trends over time. Aretrospective, descriptive epidemiological study of the Canadian population was performed to examine this.

Methods
Data on the incidence, prevalence, mortality, years lived with disability (YLDs), years of life lost(YLLs), and disability attributable life years (DALYs) for eye cancer (ICD-10 C69.0-69.8) in Canada from 1980to 2021 were derived from the Global Burden of Disease Study. Estimations were derived from cancerregistries and vital registrations. Joinpoint regression analysis was performed to evaluate the average annualpercentage change (AAPC) in each metric over time and statistically determine any inflection points. Tomeasure the economic impact of eye cancer, we estimated the value of 1 DALY at 1-3 times GDP per capita.

Results
Between 1990 and 2021, there was an absolute increase in incident cases (AAPC=1.38, CI[1.28,1,42]), prevalent cases (AAPC=1.18, CI[1.18, 1,30]), deaths (AAPC=1.24, CI[1.16, 1.30]), total YLLs(AAPC=0.61, CI[0.54, 0.68]), YLDs (AAPC=1.34, CI[1.28, 1.41], and DALYs (AAPC=0.78, CI[0.69, 0.86]) fromeye cancer. In 2021, 1673 DALYs were attributable to eye cancer, resulting in an economic burden of 88-264million USD. The average annual economic burden through this time period was 77-221 million USD.

All measures were age-adjusted and converted to rates per 100,000 people. Between 1990-2021, there was adecrease in the overall incidence (AAPC=-0.78, CI[-0.91, -0.69], prevalence (AAPC=-0.75, CI[-0.88, -0.63]),mortality (AAPC=-1.31, CI[-1.31, -1.38], YLLs (AAPC=-1.55 CI[-1.61, -1.49]), YLDs (AAPC=-0.80, CI[-0.90.-0.71]), and DALYs (AAPC=1.44, CI:[-1.53,-1.36]) (Figure 1) per capita. For all measures except YLLs, aninflection point indicated an increase in all measures from 2009-2019. A negative trend was observed from2019-2021, possibly associated with the COVID-19 pandemic.

Conclusion
As Canada’s population has grown, it has observed a growing burden of eye cancer across allmeasures under study. Per capita, Canada has seen an overall improvement in the burden of this disease.However, the results suggest that since 2009, there may be a growing burden of eye cancer, in opposition tothe prevailing trend.

 

Characterizing Trends in the Burden of Eye Cancer in Canada

 

Purpose
To critically appraise clinical evidence evaluating adjunctive usage of topical aqueous suppressants (β-blockers or carbonic anhydrase inhibitors) with intravitreal anti-VEGFs treatment for diabetic macular edema (DME), neovascular age-related macular degeneration (nAMD), and retinal vein occlusion (RVO), focusing on retinal thickness, visual acuity, treatment burden, and safety outcomes.

Methods
We performed a narrative literature review (2000–2025), identifying clinical trials, observational cohorts, and case series comparing anti-VEGF monotherapy versus anti-VEGF combined with topical aqueous suppressants. Findings were synthesized descriptively by disease group without formal meta-analysis.

Results
In DME (four small RCTs, ~100 eyes), three studies reported that adjunctive dorzolamide (± timolol) yielded 3-month CMT reductions 25–71 µm greater than anti-VEGF alone, with modest VA improvements; one contralateral-eye RCT reported no effect. In nAMD (four studies), a placebo-controlled RCT (n=52) demonstrated an additional –38 µm CST reduction at 3 months; a refractory-eye series reported similar thinning but stable acuity; and retrospective data suggested reduced injection burden 2 years with systemic β-blockers and non-significant trends toward greater CST thinning and VA gain. In RVO (two small trials, ~46 eyes), adjunct drops produced transient week-5 CRT thinning and modest CFT/CST reductions but no sustained anatomical, visual, or injection-interval benefit. Across studies, adjunctive therapy consistently lowered intraocular pressure and produced no serious adverse events.

Conclusions
Heterogeneous evidence suggests aqueous suppressants confer small, short-term anatomical benefits—particularly in DME and refractory nAMD/RVO—without consistent visual or durability improvements. Routine combined use is not recommended; well-powered prospective trials with standardized endpoints are needed to define their clinical utility.

Adjunctive Aqueous Suppressants in Anti-VEGF Therapy

 

Purpose
To evaluate associations between different intravitreal treatments and changes in choroidal thickness and visual acuity in patients with retinal vein occlusion (RVO).

Methods
We searched Cochrane Central, MEDLINE Ovid, and Embase Ovid for prospective and retrospective studies involving central or branch RVO treated with intravitreal anti-VEGF or corticosteroids. Primary outcomes were subfoveal choroidal thickness (SFCT) and best corrected visual acuity (BCVA) changes from baseline at 1, 3, 6, and 12 months. Two independent reviewers selected studies, extracted data, and assessed quality.

Results
Of 2,449 studies, 27 (1,587 eyes) met inclusion criteria. At 1 month, SFCT significantly decreased with bevacizumab (-25.80 µm, p<0.01) and dexamethasone (-17.59 µm, p=0.05), but not with ranibizumab, triamcinolone, or aflibercept. BCVA significantly improved at 1 month with dexamethasone (-0.20, p<0.01) and bevacizumab (-0.10, p=0.01). At 3 months, SFCT reduction persisted with bevacizumab (-32.27 µm, p=0.01) and dexamethasone (p=0.03), although BCVA improvements were not significant. At 6 months, only bevacizumab demonstrated continued SFCT reduction (-37.00 µm, p<0.01) and significant BCVA improvement. By 12 months, neither bevacizumab nor ranibizumab significantly affected SFCT.

Conclusions
In patients receiving intravitreal therapy for RVO, bevacizumab was associated with sustained SFCT reduction and periodic BCVA improvements up to 6 months, while dexamethasone showed shorter-term SFCT reductions. These findings may inform treatment selection and timing in clinical practice. Further studies are needed to clarify long-term effects.

 

Choroidal Thickness in Retinal Vein Occlusion Before and After Anti-VEGF and Steroid Injections

 

Purpose
Jurisdictions across North America have reported a recent epidemic of GAS infections, with rates increasing by up to 77% since 2022.1,2 We report a multicentre series of aggressive, periocular necrotizing fasciitis (NF), and the diverse techniques used to debride and reconstruct.Purpose: Jurisdictions across North America have reported a recent epidemic of GAS infections, with rates increasing by up to 77% since 2022.1,2 We report a multicentre series of aggressive, periocular necrotizing fasciitis (NF), and the diverse techniques used to debride and reconstruct.

Study Design: Case series.

Methods
Charts of patients with periocular necrotizing fasciitis between 2022-2025 were reviewed. Written consent for patient information to be collected was obtained. Approval was waived from the University of Calgary Conjoint Health Research Ethics Board.

Results
19 patients were identified. Ages ranged from 4-69 years (median 55.5 years), and 16 (84%) were male. 7 (37%) had concurrent substance use, 6 (32%) had diabetes, 2 (11%) were immunocompromised, and 4 (21%) were healthy. Distribution of NF included preseptal upper eyelid (100%), preseptal lower eyelid (9, 47%), posterior upper and lower eyelids in 2 cases, and orbital in 2 cases. 5 (26%) cases were bilateral. Regional or distant infected wounds (forehead, palate and nasopharynx, 5th finger) were associated in 3 cases, and extensive metastatic NF was observed in 1 delayed presentation (occiput, neck, leg, and scrotum). 5 cases were associated with fasciitis tracking down the neck via co-planar superficial temporal fascia. A conservative, skin-sparing debridement was attempted in 10 cases (53%). 100% of cases grew GAS, and 5 cases were polymicrobial (commonly with Staphylococcus aureus). Coronavirus-19 or influenza tested positive in 2 patients. Reconstructions included skin grafting in 7 cases (37%) and delayed primary closure in 5 cases (26%). 2 bare-bone defects were addressed using a temporalis turnover flap and biodegradable temporizing matrix prior to skin grafting. 1 case received a paramedian forehead flap. 1 case with full-thickness necrosis of the upper and lower eyelids received a periosteal flap and contralateral free tarsal graft to reconstruct posterior lamellar support, a forehead rotation flap, and bladder matrix to temporize. 1 case required enucleation for an ischemic, necrotic globe. Amniotic membrane was used in 1 case. 4 patients received negative pressure wound therapy to promote granulation before reconstruction, and 1 patient received hyperbaric oxygen. 3 patients received steroids after infection had cleared. Considering initial defects, outcomes were reasonable at median follow-up (4 months, range 0.5-12 months). Major complications included exposure keratopathy (n=1), skin graft failure (n=1), superonasal pedicle loss (n=1), and death in the 1 case with metastatic NF. Mild lagophthalmos was seen in 4 patients.

Conclusion
This series illustrates the diversity and complexity of NF presentations and the wide array of approaches used by different surgeons to debride and reconstruct. With GAS on the rise worldwide, providers should remain vigilant for periocular NF and treat it early and aggressively with tissue- and globe-sparing approaches.

 

Epidemic Group A Streptococcus: Periocular Necrotizing Fasciitis

 

Purpose
Congenital ptosis is a condition attributed to dysgenesis of the levator palpebrae superioris. Here, we report orbital asymmetry associated with congenital ptosis.

Study Design Prospective observational study.

Methods
19 consecutive patients with congenital ptosis were enrolled. Demographic data and associated ophthalmic and orbital conditions were documented. Exophthalmometry was performed by 2 independent observers, and average inter-eye differences were calculated. Measurements were obtained upright in clinic, or for younger children, under general anaesthetic at the time of ptosis surgery. Where cooperation permitted, axial length was measured using optical biometry. REB approval was obtained.

Results
19 patients were enrolled from November 2023 to April 2025. 11 patients (58%) were female. Average age was 6.7 ± 6.3 years (range 7 months to 23 years). The right eye was more ptotic in 10 cases (53%). 4 cases (22%) were bilateral. Associated conditions were observed in 9 patients (47%), and were all encountered on the more ptotic side. These included NLDO (n=3), superotemporal orbital dermoid cysts (n=3), and Marcus-Gunn jaw wink (n=3). Blepharoptosis-phimosis epicanthus inversus syndrome (n=1) was seen in 1 patient. Exophthalmometry consistently demonstrated relative enophthalmos on the more ptotic side (n=18, 95%), with an average of -1.23 ± 0.54 mm of inter-eye difference (p<0.001, t-test). Relative enophthalmos was independent of differences in axial length (R² = -0.02, p=0.41) or age (R² = 0.03, p=0.45) by multiple linear regression. For the more ptotic side, average difference in axial length was -0.14 ± 0.38 mm between eyes, which was not significant (p=0.29, t-test).

Conclusion
Congenital ptosis was reliably associated with relative enophthalmos independent of globe size, and a high incidence of other orbital conditions. In addition to another Calgary study demonstrating other tissues involved in this condition (e.g. Muller’s muscle),² and facial asymmetries previously reported in association with congenital ptosis,¹ these results suggest that deficits in orbital volume, or other processes in orbital embryogenesis, may also be implicated in this condition.

 

Orbital Asymmetry in Children with Congenital Ptosis

 

Purpose
Making quick and accurate saccades are crucial to the thousands of eye movements we make each day. Oculomotor deficits are prevalent post-stroke, yet clinical assessments of saccades are crude. Creating more sensitive and robust assessments for eye movements poststroke is important for improving rehabilitation outcomes. Here, we aimed to characterize and assess saccades to visual targets in stroke survivors in the subacute phase of stroke. Methods: We assessed saccades to visual targets in 52 stroke survivors (median 25 days post-stroke) and
109 control participants using a Kinarm robotic exoskeleton and an Eyelink 1000 eye tracker. In the visual saccade task, participants fixated on a central visual target and made saccades (10cm horizontally) to peripheral visual targets. We measured accuracy, latency, and peak velocity of the first saccade made after the central visual target turned off, as well as the accuracy of the closest saccade made to the peripheral target (corrective accuracy). Age-, sex-, and handednessadjusted z-scores were created for stroke participants using control data to generate normative models.

Results
Stroke survivors had impairments in visual saccade accuracy (38% impaired), latency (21%), and peak velocity (19%). Additionally, 48% of stroke survivors had abnormal corrective accuracy. However, only 15% of stroke survivors were diagnosed with eye movement problems during their hospital stay.

Conclusions
Many stroke survivors had impaired saccades to visual targets despite no clinical diagnosis of eye movement issues. Understanding the prevalence and characteristics of saccadic deficits post-stroke may help inform how we design and deliver stroke rehabilitation.

 

Precision Eye Tracking Reveals Saccadic Dysfunction Post-Stroke