Publications by authors named "Graham Trope"
Purpose: To evaluate long-term retention, compliance, and performance of glaucoma patients using a virtual reality portable perimeter to monitor visual fields (VFs) at home.
Design: Prospective, longitudinal, cohort study.
Subjects: Twenty-five glaucoma patients with stable and reliable VFs (average age 67.
Article Synopsis
- - The study aimed to estimate the prevalence of glaucoma in Canada using self-reports and various tests like Frequency Doubling Technology Perimetry (FDT), optic nerve measurements, and intraocular pressure data.
- - Among 2,600-4,100 participants aged 40-79, the findings showed glaucoma prevalence rates ranging from 0.7% to 10.3%, with 16.3% classified as "glaucoma suspects."
- - Notably, 37.5% of those with definite glaucoma didn't know they had the condition, highlighting the importance of awareness and testing.
Objective: To obtain prescription eyewear in Ontario, eye exams must be performed by optometrists or ophthalmologists (eye care providers [ECPs]). In 2004, government-insured routine eye exams were delisted for Ontarians aged 20-64 leaving eye exam coverage only for those aged ≤19 and 65+. We assessed whether having eyewear insurance impacts Ontarians' utilization of ECPs.
View Article and Find Full Text PDFArticle Synopsis
- Perimetry and optical coherence tomography (OCT) are important for monitoring glaucoma, but combining their data is difficult due to differing formats.
- To address this, researchers created an autoencoder data fusion (AEDF) model that effectively merges data from both methods, enhancing detection of visual field (VF) progression while preserving key OCT features.
- In a study with 2,504 tests from 140 patients, the AEDF outperformed standard methods and a Bayesian model, achieving a higher F1 score (0.60) for VF progression detection within the first two years of follow-up.
Article Synopsis
- Visual impairment is a significant issue related to diabetes in Canada, prompting a study to analyze trends among individuals with and without the condition from 1994 to 2014.* -
- Data from national surveys indicated that prevalence of visual impairment decreased for both diabetics (from 7.37% to 3.03%) and non-diabetics (from 3.72% to 1.69%) over the years, showing improvements in eye health.* -
- Despite stronger initial prevalence rates in diabetics, both groups experienced similar reductions in visual impairment, suggesting successful collaborative efforts across various sectors in Canada.*
A Data-Driven Model for Simulating Longitudinal Visual Field Tests in Glaucoma.
Transl Vis Sci Technol
June 2023
Purpose: To develop a simulation model for glaucomatous longitudinal visual field (VF) tests with controlled progression rates.
Methods: Longitudinal VF tests of 1008 eyes from 755 patients with glaucoma were used to learn the statistical characteristics of VF progression. The learned statistics and known anatomic correlations between VF test points were used to automatically generate progression patterns for baseline fields of patients with glaucoma.
Purpose: Glaucoma is a progressive optic neuropathy that damages retinal ganglion cells and a neurodegenerative disease as it affects neural structures throughout the brain. In this study, we examined binocular rivalry responses in patients with early glaucoma in order to probe the function of stimulus-specific cortical areas involved in face perception.
Methods: Participants included 14 individuals (10 females, mean age 65 ± 7 years) with early pre-perimetric glaucoma and 14 age-matched healthy controls (7 females, mean age 59 ± 11 years).
Purpose: To evaluate the effect of prophylactic aqueous suppressants immediately post-Ahmed glaucoma valve (AGV) surgery on the rate of hypertensive phase and success.
Methods: Retrospective case-control study of 80 eyes with refractory glaucoma undergoing AGV surgery. Forty eyes in the intervention group (preoperative aqueous suppressants continued postoperatively) and 40 in the control group (all glaucoma drops stopped after surgery and reintroduced as required) were included in this study.
Prcis: This study examined the integrity of binocular summation function in patients with mild glaucoma. We found that binocular summation of visual acuity is preserved in these patients, despite their reduced monocular inputs.
Purpose: Binocular summation represents superiority of binocular to monocular performance.
Purpose: This study tested perceptual grouping during binocular rivalry to probe the strength of neural connectivity of the visual cortex involved in early visual processing in patients with mild glaucoma.
Methods: Seventeen patients with mild glaucoma with no significant visual field defects and 14 healthy controls participated. Rivalry stimuli were 1.
Cataract prevalence following a nationwide policy to shorten wait time for cataract surgery.
Med Hypothesis Discov Innov Ophthalmol
August 2021
Background: Cataract is an age-related eye disease. Visual impairment from cataract can be restored by cataract surgery. In 2004 the Canadian federal government invested in a multibillion dollar wait time strategy to shorten the wait time for cataract surgery, a government-insured health service in all Canadian jurisdictions.
View Article and Find Full Text PDFObjective: In 2004, government-funded routine eye exams were discontinued for individuals aged 20-64 years in Ontario. We assessed whether this policy change reduced the rate of new glaucoma diagnoses.
Design: Cohort-based time-series analysis.
Introduction: Eye care in many countries is provided by optometrists, ophthalmologists, primary care providers (PCPs, including family physicians and pediatricians) and emergency department (ED) physicians. In the province of Prince Edward Island (PEI), Canada, optometric services are not government-insured, while services provided by other eye care providers are government-insured. Clinics of optometrists, PCPs and ED physicians are widely distributed across the island.
View Article and Find Full Text PDFPurpose: To summarize COVID-19 research endeavors by ophthalmologists/researchers in terms of publication numbers, journals and author countries, and to detail key findings.
Methods: The LitCovid database was systematically reviewed for ophthalmology-focused COVID-19 articles. The quality of the evidence was assessed for articles investigating conjunctivitis in COVID-19 patients.
Objective: To determine the proportion of glaucoma patients in Ontario aged 25-64 who lack insurance coverage for glaucoma medications and to assess the frequency of cost-related nonadherence to glaucoma medications.
Design: Cross-sectional study.
Participants: Glaucoma patients on medication from 2 glaucoma clinics in Toronto, Ontario.
Purpose: To evaluate the effect of changes in position in the trans-lamina cribrosa pressure difference (TLCPD) by simultaneously measuring and comparing intracranial pressure (ICP) with intraocular pressure (IOP) in seated and supine positions.
Design: Prospective cohort study.
Participants: Patients admitted to the neurosurgery unit at Toronto Western Hospital with an external ventricular drain placed for ICP monitoring.
Objective: To determine the proportion of indexed ophthalmology journals with article processing charges (APCs) and potential factors associated with APCs.
Design: Cross-sectional study.
Participants: Web of Science-indexed Ophthalmology journals in 2019.
Background: In 2004, Ontario delisted routine eye examinations for people aged 20-64 years, potentially encouraging patients seeking eye care to visit government-insured primary care providers (PCPs) rather than optometrists whose services had been deinsured. We investigated if utilization of PCP services for nonrefractive eye conditions increased after 2004 among Ontarians who were affected by the delisting.
Methods: We conducted a comparative analysis of the utilization of PCP services for nonrefractive eye conditions in Ontario using administrative data from 2000 to 2014.
Objective: To present outcomes of Descemet membrane endothelial keratoplasty (DMEK) in eyes with prior trabeculectomy or a glaucoma drainage device (GDD).
Methods: A retrospective case series, including patients that had previously undergone trabeculectomy and/or GDD implantation, who later underwent DMEK between 2013 and 2016 at Toronto Western Hospital and the Kensington Eye Institute. Outcome measures: best spectacle-corrected visual acuity (BSCVA), endothelial cell (EC) density, intraoperative and postoperative complications.
Objectives: To report on the 2003-2013 trends in sociodemographics, financial support, and use of vision care benefits by visually impaired (VI) individuals in the Ontario Disability Support Program (ODSP).
Design: Retrospective analysis.
Participants: ODSP recipients with a VI diagnosis from 2003 to 2013.
Glaucoma is considered a progressive optic neuropathy because of the damage and death of the retinal ganglion cells. It is also a neurodegenerative disease because it affects neural structures in the visual system and beyond, including the corpus callosum-the largest white matter structure involved in inter-hemispheric transfer of information. In this study we probed the dysfunction of the inter-hemispheric processing in patients with mild glaucoma using the phenomenon of binocular rivalry.
View Article and Find Full Text PDFArticle Synopsis
- * A study compared 20 patients with mild open-angle glaucoma to 25 age-matched controls, evaluating the efficiency of inter-hemispheric transfer through binocular rivalry.
- * Results showed that while control participants had more failure in inter-hemispheric wave propagation, glaucoma patients had equally high failure rates and longer wave propagation times, indicating changes in visual processing despite normal functional test results.