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"Trope, Graham E"
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Reduced social participation among seniors with self-reported visual impairment and glaucoma
2019
Social participation benefits health. We assessed the relationship between self-reported visual impairment (VI) and glaucoma versus seniors' social participation.
Data from individuals aged ≥65 years responding to the Canadian Community Health Survey Healthy Aging 2008/2009 (n = 16,369) was analyzed. Participation in eight social activities by seniors with and without self-reported VI or glaucoma was compared.
Seniors with VI had significantly reduced participation (p<0.05) in sports/physical activities (18.0% vs. 33.6%), family/friendship activities outside the household (39.7% vs. 53.0%), service club/fraternal organization activities (11.4% vs. 18.4%), volunteer/charity work (13.4% vs. 24.9%), educational/cultural activities (16.2% vs. 24.5%), and other social recreational activities (21.6% vs. 31.0%) compared to those without VI. Differences in participation in church/religious activities (40.6% vs. 44.5%) and community/professional association activities (15.3% vs. 18.0%) were non-significant between seniors with and without VI. Seniors with glaucoma versus those without had significantly reduced participation (p<0.05) in family/friendship activities (46.6% vs. 52.9%), sports/physical activities (26.0% vs. 33.6%) and volunteer/charity work (20.4% vs. 24.9%). No participation in any social activity was significantly higher among seniors with VI versus those without (10.1% vs. 2.9%, p<0.05), but was similar among seniors with and without glaucoma (3.9% vs. 3.1%, p>0.05). After adjusting for the effects of age, sex, education, household income, ethnicity, job status and chronic diseases (adjusted odds ratio, aOR = 3.4 (95% confidence interval (CI) 2.0-5.8), seniors with VI but no glaucoma were more likely not to engage in any social activities compared to seniors without VI and no glaucoma. Seniors with glaucoma but without VI had a similar level of non-participation (aOR = 0.9, 95%% CI 0.5-1.7).
Significantly reduced social participation was found across six community activities among seniors with self-reported VI and in three activities among those with self-reported glaucoma. Policies and programs that help seniors with VI or glaucoma engage in social activities are needed.
Journal Article
Intra- and inter-hemispheric processing during binocular rivalry in mild glaucoma
by
Trope, Graham E.
,
Samet, Saba
,
González, Esther G.
in
Aged
,
Binocular vision
,
Biology and Life Sciences
2020
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. Patients with mild glaucoma and no measurable visual field defects and age-matched controls underwent a thorough visual assessment. Then they participated in a series of psychophysical tests designed to examine the binocular rivalry derived from intra- and inter-hemispheric processing. Static horizontal and vertical sinewave gratings were presented dichoptically using a double-mirror stereoscope in 3 locations: centrally, to probe inter-hemispheric processing, and peripherally to the left or to the right, to probe intra-hemispheric processing. Although the two groups were matched in functional measures, rivalry rate of the glaucoma group was significantly lower than that of the control group for the central location, but not for the peripheral location. These results were driven mainly by the patients with normal tension glaucoma whose average rivalry rate for the central location (from which information reaches the two hemispheres) was almost half (46% lower) that of the controls. These results indicate a dysfunction in inter-hemispheric transfer in mild glaucoma that can be detected behaviourally before any changes in standard functional measures.
Journal Article
Comparison of trabeculectomy versus Ex-PRESS: 3-year follow-up
2016
AimsTo compare the outcomes of Ex-PRESS versus trabeculectomy at 3 years.MethodsConsenting patients aged 18–85 years with medically uncontrolled open-angle glaucoma scheduled for trabeculectomy were included in this study. 63 subjects were randomised to undergo Ex-PRESS (32) or trabeculectomy (31). Follow-up data included intraocular pressure (IOP), glaucoma medications, visual acuity (VA), complications and additional interventions. Complete success was defined as IOP between 5 and 18 mm Hg and 20% reduction from baseline without glaucoma medications, while qualified success was with or without glaucoma medications.ResultsComplete success at 2 and 3 years was 43% vs 42% (p=0.78) and 35% vs 38% (p=0.92) in Ex-PRESS versus trabeculectomy, respectively. Qualified success at 2 and 3 years was 59% vs 76% (p=0.20) and 52% vs 61% (p=0.43) in Ex-PRESS versus trabeculectomy, respectively. Mean IOP at 2 and 3 years was 12.5±5.1 mm Hg vs 10.3±3.7 mm Hg (p=0.07) and 13.3±4.5 mm Hg vs 11.1±4.4 mm Hg (p=0.10) for Ex-PRESS versus trabeculectomy, respectively. At 3 years, 47.6% of Ex-PRESS and 50% of trabeculectomy patients were on glaucoma medications (p=1.00). No difference in VA was found after 3 years (logarithm of minimum angle of resolution 0.43±0.4 vs 0.72±0.8 for Ex-PRESS vs trabeculectomy, p=0.11). When excluding patients who underwent reoperation VA was better in the Ex-PRESS group at 1, 2 and 3 years. There were no complications after the first year in either group.ConclusionsWe found no difference in success rates, mean IOP or other secondary outcomes between Ex-PRESS and trabeculectomy after 3 years of follow-up.Trial registration numberNCT01263561; post results.
Journal Article
Atypical responses to faces during binocular rivalry in early glaucoma
by
Trope, Graham E.
,
Buys, Yvonne M.
,
Issashar Leibovitzh, Galia
in
Acuity
,
binocular rivalry
,
Binocular vision
2023
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.
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). The 2 groups were equivalent in visual acuity and stereo-acuity. Three binocular rivalry stimulus pairs were used: (1) real face/house, (2) synthetic face/noise patch, and (3) synthetic face/spiral. For each stimulus pair, the images were matched in size and contrast level; they were viewed dichotically, and presented centrally and eccentrically at 3 degrees in the right (RH) and in the left hemifield (LH), respectively. The outcome measures were rivalry rate (i.e., perceptual switches/min) and time of exclusive dominance of each stimulus.
For the face/house stimulus pair, rivalry rate of the glaucoma group (11 ± 6 switches/min) was significantly lower than that of the control group (15 ± 5 switches/min), but only in the LH location. The face dominated longer than the house in the LH for both groups. Likewise, for the synthetic face/noise patch stimulus pair, rivalry rate of the glaucoma group (11 ± 6 switches/min) was lower than that of the control group (16 ± 7 switches/min) in the LH, but the difference failed to reach significance. Interestingly, the mixed percept dominated less in glaucoma than in the control group. For the synthetic face/spiral stimulus pair, the glaucoma group had lower rivalry rate at all 3 stimulus locations.
This study reveals atypical responses to faces during binocular rivalry in patients with early glaucoma. The results may be suggestive of early neurodegeneration affecting stimulus-specific neural structures involved in face processing starting in the pre-perimetric phase of the disease.
Journal Article
Perceptual Grouping During Binocular Rivalry in Mild Glaucoma
by
Trope, Graham E
,
Buys, Yvonne M
,
Issashar Leibovitzh, Galia
in
Binocular vision
,
Brain research
,
COVID-19
2022
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 1.8 deg-diameter discs, containing horizontal or vertical sine-wave gratings, viewed dichoptically. To test grouping, 2 spatially separated identical stimuli were presented eccentrically to the same or different eyes and to the same or different hemifields. The outcome measures were time of exclusive dominance of the grouped percept (i.e., percept with synchronized orientations), rivalry rate, and epochs of exclusive dominance. Results: For both groups, grouping occurred primarily for the matching orientations in the same eye/same hemifield (MO SE/SH) and for the matching orientations in the same eye/different hemifield (MO SE/DH) conditions. Time dominance of the grouped percept of the glaucoma group was similar to that of the control group in all conditions. Rivalry rates in the MO SE/SH and MO SE/DH conditions were significantly larger in the control group than in the glaucoma group. The epochs of exclusive dominance of the grouped percept in the MO SE/SH condition were a median of 48ms longer for the control group, but a median of 116ms shorter for the glaucoma group when compared to those in the MO SE/DH condition. Conclusions: Patients with mild glaucoma show clear impairments in binocular rivalry while evidence for deficits in perceptual grouping could be inferred only indirectly. If these deficits truly exist, they may have implications for higher levels of visual processing such as object recognition and scene segmentation, but these predictions remain to be tested in future studies.
Journal Article
Using Fused Data from Perimetry and Optical Coherence Tomography to Improve the Detection of Visual Field Progression in Glaucoma
2024
Perimetry and optical coherence tomography (OCT) are both used to monitor glaucoma progression. However, combining these modalities can be a challenge due to differences in data types. To overcome this, we have developed an autoencoder data fusion (AEDF) model to learn compact encoding (AE-fused data) from both perimetry and OCT. The AEDF model, optimized specifically for visual field (VF) progression detection, incorporates an encoding loss to ensure the interpretation of the AE-fused data is similar to VF data while capturing key features from OCT measurements. For model training and evaluation, our study included 2504 longitudinal VF and OCT tests from 140 glaucoma patients. VF progression was determined from linear regression slopes of longitudinal mean deviations. Progression detection with AE-fused data was compared to VF-only data (standard clinical method) as well as data from a Bayesian linear regression (BLR) model. In the initial 2-year follow-up period, AE-fused data achieved a detection F1 score of 0.60 (95% CI: 0.57 to 0.62), significantly outperforming (p < 0.001) the clinical method (0.45, 95% CI: 0.43 to 0.47) and the BLR model (0.48, 95% CI: 0.45 to 0.51). The capacity of the AEDF model to generate clinically interpretable fused data that improves VF progression detection makes it a promising data integration tool in glaucoma management.
Journal Article
Comparison of United States and Canadian Glaucoma Medication Costs and Price Change from 2006 to 2013
by
Buys, Yvonne M.
,
Trope, Graham E.
,
Schlenker, Matthew B.
in
Beta blockers
,
Brand names
,
Cost control
2015
Objective. Compare glaucoma medication costs between the United States (USA) and Canada. Methods. We modelled glaucoma brand name and generic medication annual costs in the USA and Canada based on October 2013 Costco prices and previously reported bottle overfill rates, drops per mL, and wastage adjustment. We also calculated real wholesale price changes from 2006 to 2013 based on the Average Wholesale Price (USA) and the Ontario Drug Benefit Price (Canada). Results. US brand name medication costs were on average 4x more than Canadian medication costs (range: 1.9x–6.9x), averaging a cost difference of $859 annually. US generic costs were on average the same as Canadian costs, though variation exists. US brand name wholesale prices increased from 2006 to 2013 more than Canadian prices (US range: 29%–349%; Canadian range: 9%–16%). US generic wholesale prices increased modestly (US range: −23%–58%), and Canadian wholesale prices decreased (Canadian range: −38%–0%). Conclusions. US brand name glaucoma medications are more expensive than Canadian medications, though generic costs are similar (with some variation). The real prices of brand name medications increased more in the USA than in Canada. Generic price changes were more modest, with real prices actually decreasing in Canada.
Journal Article
The Effect of Government-Uninsured Optometric Services on the Use of Primary Care Providers
by
El-Defrawy, Sherif
,
Jeon, William
,
Trope, Graham E
in
Canada Health Act
,
Diabetes
,
emergency physicians
2021
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. Clinics of ophthalmologists however are concentrated in the capital city Charlottetown.
To investigate if more patients visited government-insured PCPs and EDs for eye care when local optometric services are government-uninsured and government-insured ophthalmologists are potentially distant.
From PEI physician billing database, we identified all patients with an ocular diagnosis from 2010-2012 using International Classification of Diseases, 9th Revision (ICD-9) codes. The utilization of government-insured PCPs and EDs in five geographical regions was assessed utilizing patients' residential postal code. Of the five regions, Prince was the region farthest from the capital Charlottetown.
Compared to utilization of government-insured PCPs for ocular diagnoses in Charlottetown (13.5% in 2010, 95% confidence interval [CI] 12.9-14.0%), the utilization in Prince (22.4% in 2010, 95% CI 21.7-23.1%) was nearly double (p<0.05). The utilization of ED physicians for ocular diagnoses was similarly double in Prince (8.8%, 95% CI 8.3-9.3%) versus Charlottetown (4.1%, 95% CI 3.8-4.5%). The utilization of ophthalmologists however was significantly lower in Prince (43%, 95% CI 41.4-42.9%) versus Charlottetown (56.3%, 95% CI 55.6-57.1%). Similar trends remained throughout 2010-2012.
When optometric services are government-uninsured and government-insured ophthalmologist services are geographically distant, ocular patients utilized PCPs and ED physicians more frequently. Due to different levels of training and available equipment for eye examinations among PCPs, ED physicians and optometrists, the quality of eye care and cost-effectiveness of increased use of PCPs and ED physicians for ocular management warrant further investigation.
Not applicable.
Journal Article
Twenty-four hour intraocular pressure monitoring with the SENSIMED Triggerfish contact lens: effect of body posture during sleep
2017
PurposeTo determine the difference in relative intraocular pressure (IOP) measured by the SENSIMED Triggerfish (TF) contact lens in flat compared with 30° head-up sleeping positions in patients with progressive primary open-angle glaucoma or normotensive glaucoma, based on recent or recurrent disc haemorrhage.DesignProspective, randomised, cross-over, open-label comparative study.MethodsIOP was monitored for 24 hours using TF on two separate sessions. Patients were randomly assigned to sleep flat one night and 30° head-up the other. Outputs in arbitrary units were obtained. Sleep and wake periods were defined as 22:00–6:00 and 8:00–22:00, respectively. Mean TF values during sleep and wake periods and wake–sleep and sleep–wake slopes were calculated for each session. TF output signals were compared between positions.ResultsTwelve subjects completed the study. Significant mean positive slopes were noted during the sleep period for both positions (p<0.01). No significant differences in the TF mean values were observed between positions (p=0.51). Six (54%) subjects had mean TF values significantly higher during the flat supine session, while four (36%) subjects had higher values during the head-up session. A significant increase in Goldmann IOP (p=0.001) and TF (p=0.02) measurements were observed after 24 hours of TF wear (‘drift phenomenon’).ConclusionsSleep position affects IOP as measured by TF in some patients with progressive glaucoma. The upward drift in TF output detected in >50% of the subjects requires further investigation to establish whether the increased output values over time are an artefact induced by the TF or a real change in IOP.Trial registration numberNCT01351779
Journal Article