Sensitivity and specificity of the uniform field electroretinogram in glaucoma detection in comparison to the pattern electroretinogram.

PURPOSE: To determine the ability of the photopic negative response (PhNR) of the uniform field electroretinogram (UF-ERG) to identify early glaucomatous changes in comparison to the checkerboard and bar stimuli of the pattern electroretinogram (PERG). METHODS: Forty-nine glaucoma patients were classified into two groups: glaucoma-suspect (23 eyes) and early to moderate glaucoma (30 eyes), based on their clinical examination and the results of standard automated perimetry. Thirty patients (30 eyes) with intraocular pressures (IOP) of 21 mmHg or less, with no history of reported high IOP, were included as controls. PERG and UF-ERG recordings were obtained on a Diagnosys D-341 Attaché-Envoy System. Visual field testing was done only for glaucoma-suspect and glaucoma patients. RESULTS: All three tests (PERG bar stimulus, PERG checkerboard stimulus and PhNR) displayed significantly prolonged peak times for glaucoma and glaucoma-suspect patients, with delays ranging from 7.8 to 14.8%, depending on the test. The PERG bar stimulus also showed a significantly lower N95 amplitude for both glaucoma groups (with reductions of 26.0% and 33.0% for glaucoma-suspect and glaucoma groups, respectively). The PERG checkerboard N95 amplitude component had high sensitivity for detecting glaucoma patients but a low specificity (97% and 37%, respectively; AUC = 0.61). Overall, the PhNR peak time showed the highest sensitivity and specificity (77% and 90%, respectively; AUC = 0.87). CONCLUSIONS: PERG bar stimuli and the PhNR of the UF-ERG can be used in the clinical setting to detect glaucoma-related changes in glaucoma-suspect and glaucoma patients. However, our data confirm that the PhNR peak time has the best combined sensitivity and specificity.

OUTCOMES OF VITRECTOMY IN TERSON SYNDROME: A Multicenter Canadian Perspective.

PURPOSE: To characterize the presentation of Terson syndrome, the occurrence of a vitreous hemorrhage in association with intracranial hemorrhage, and report on the outcomes of vitrectomy at two major centers in Canada. METHODS: Retrospective chart review of consecutive patients with Terson syndrome undergoing vitrectomy by retina specialists over the last 10 years. Primary outcome was the change in best-corrected visual acuity (BCVA) at 3 months from baseline. Secondary outcomes included the association between baseline BCVA and final BCVA, and the association between final BCVA and timing of surgery (early vs. later than 90 days). RESULTS: A total of 14 eyes of 11 patients were included. The mean time between observation of intraocular hemorrhage and vitrectomy was 160 days. Baseline preoperative BCVA was logarithm of the minimum angle of resolution 1.57 ± 1.03 (Snellen 20/740), which improved to logarithm of the minimum angle of resolution 0.53 ± 0.82 (Snellen 20/70) at the final postoperative follow-up, P = 0.01. Baseline BCVA was not significantly correlated with final BCVA, Spearman's rho = 0.016, P = 0.957. Final BCVA did not significantly differ between those who had surgery before 90 days compared with after 90 days, P = 0.087. CONCLUSION: Vitrectomy is safe and effective and should be considered for nonclearing vitreal bleeding due to Terson syndrome. Ocular hemorrhaging in Terson syndrome can be observed conservatively for spontaneous improvement without the risk of reduced visual potential. Ophthalmic evaluation should be considered promptly after intracranial hemorrhage.

Atypical responses to faces during binocular rivalry in early 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). 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. Results: 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. Conclusion: 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.

Trends in Canadian ophthalmology residency match outcomes.

BACKGROUND: To date, there exists no formal assessment of the competitiveness of the residency match for Canadian ophthalmology programs. The primary objective of this study was to use Canadian Resident Matching Service (CaRMS) data to describe trends in the number of positions, number of applicants and level of competition for the Canadian ophthalmology match. METHODS: The number of positions and the number of applicants for each ophthalmology program were received from CaRMS for each cycle of the match from 2006-2017. The level of competition was calculated by dividing total number of applicants by the total number of positions in any given year. RESULTS: The level of competition was consistently high with a median number of 2.0 applicants per anglophone Canadian Medical Graduate (CMG) position, 2.6 applicants per francophone CMG position and 32.5 applicants per International Medical Graduate (IMG) position. Over the study period, the level of competition decreased for francophone CMG and IMG positions and did not change for anglophone CMG positions. CONCLUSION: Consistently there are a greater number of applicants than positions for Canadian ophthalmology residency programs and therefore CMG applicants should be encouraged to apply to more than one discipline. The trends in the number of residency positions can be used to update supply projections for ophthalmologists and guide human resource planning.

CONTEXTE: À ce jour, il n'existe aucune évaluation officielle de la compétitivité du jumelage des résidents pour les programmes canadiens d'ophtalmologie. L'objectif principal de cette étude était d'utiliser les données du Service canadien de jumelage des résidents (CaRMS) pour décrire les tendances dans le nombre de postes, le nombre de candidats et le niveau de compétitivité pour le jumelage canadien en ophtalmologie. MÉTHODES: Le nombre de postes et le nombre de candidats pour chaque programme d'ophtalmologie ont été reçus du CaRMS pour chaque cycle du jumelage de 2006 à 2017. Le niveau de compétitivité a été calculé en divisant le nombre total de candidats par le nombre total de postes pour chaque année. RÉSULTATS: Le niveau de compétitivité était constamment élevé avec un nombre médian de 2,0 candidats par poste pour les diplômés canadiens en médecine (DCM) anglophones, 2,6 candidats par poste pour les DCM francophones et 32,5 candidats par poste pour les dipl00F4més internationaux en médecine (DIM). Au cours de la période de l'étude, le niveau de compétitivité a diminué pour les postes pour les DCM et DIM francophones et est demeuré inchangé pour les postes pour les DCM anglophones. CONCLUSIONS: On retrouve constamment un plus grand nombre de candidats que de postes pour les programmes canadiens de résidence en ophtalmologie et, par conséquent, les candidats DCM doivent être encouragés à postuler dans plus d'une discipline. Les tendances dans le nombre de postes de résidence peuvent être utilisées pour mettre à jour les prévisions de postes pour les ophtalmologistes et guider la planification des ressources humaines.

The Muranga Teleophthalmology Study: A Comparison of Virtual (Teleretina) Assessment with in-person Clinical Examination to Diagnose Diabetic Retinopathy and Age-related Macular Degeneration in Kenya.

PURPOSE: This study compares a web-based teleophthalmology assessment with a clinical slit lamp examination to screen for diabetic retinopathy (DR) and age-related macular degeneration (AMD) among diabetic patients in a rural East African district. METHODS: Six hundred and twelve eyes from 306 diabetic patients underwent both a clinical slit lamp examination and a teleretina (TR) assessment by an experienced ophthalmologist. Both assessments were compared for any DR and AMD using the early treatment diabetic retinopathy study and age-related eye disease study grading scales, respectively. RESULTS: Of the 612 TR assessment photos, 74 (12%) were deemed ungradable due to media opacities, poor patient cooperation, or unsatisfactory photographs. The ability to detect DR and AMD showed a fair agreement (kappa statistic 0.27 and 0.23, respectively) between the TR and clinical slit lamp examination. Relative to a clinical slit lamp evaluation, a positive TR diagnosis carried a 75.0% positive predictive value when diagnosing DR and a 27.3% positive predictive value when diagnosing AMD. A negative TR diagnosis carried a 97.2% negative predictive value for the diagnosis of DR and a 98.1% negative predictive value for the diagnosis of AMD. CONCLUSION: When comparing TR assessments to clinical slit lamp examinations to diagnose DR and AMD, there was a fair agreement. Although further validation is needed, the TR approach provides a promising method to diagnose DR and AMD, two major causes of ocular impairment worldwide.

Building a framework for global health learning: an analysis of global health concentrations in Canadian medical schools.

PURPOSE: This study set out to explore the current state of global health concentrations in Canadian medical schools and to solicit feedback on the barriers and challenges to implementing rigorous global health concentration programs. METHOD: A set of consensus guidelines for global health concentrations was drafted through consultation with student and faculty leaders across Canada between May 2011 and May 2012. Drawing on these guidelines, a formal survey was sent to prominent faculty at each of the 14 English-speaking Canadian medical schools. A thematic analysis of the results was then conducted. RESULTS: Overall, the guidelines were strongly endorsed. A majority of Canadian medical schools have programs in place to offer global health course work, extracurricular learning opportunities, local community service-learning, low-resource-setting clinical electives, predeparture training, and postreturn debriefing. Although student evaluation, global health mentorship, and knowledge translation projects were endorsed as important components, few schools had been successful in implementing them. Language training for global health remains contested. Other common critiques included a lack of time and resources, and difficulties in setting standards for student evaluation. CONCLUSIONS: The results suggest that these guidelines are appropriate and, at least for the major criteria, achievable. Although many Canadian schools offer individual components, the majority of schools have yet to develop formally structured concentration programs. By better articulating guidelines, a standardized framework can aid in the establishment and refinement of future programs.

The Muranga Teleophthalmology Study: Comparison of Virtual (Teleglaucoma) with in-Person Clinical Assessment to Diagnose Glaucoma.

PURPOSE: While the effectiveness of teleophthalmology is generally accepted, its ability to diagnose glaucomatous eye disease remains relatively unknown. This study aimed to compare a web-based teleophthalmology assessment with clinical slit lamp examination to screen for glaucoma among diabetics in a rural African district. MATERIALS AND METHODS: Three hundred and nine diabetic patients underwent both the clinical slit lamp examination by a comprehensive ophthalmologist and teleglaucoma (TG) assessment by a glaucoma subspecialist. Both assessments were compared for any focal glaucoma damage; for TG, the quality of photographs was assessed, and vertical cup-to-disk ratio (VCDR) was calculated in a semi-automated manner. In patients with VCDR > 0.7, the diagnostic precision of the Frequency Doubling Technology (FDT) C-20 screening program was assessed. RESULTS: Of 309 TG assessment photos, 74 (24%) were deemed unreadable due to media opacities, patient cooperation, and unsatisfactory photographic technique. While the identification of individual optic nerve factors showed either fair or moderate agreement, the ability to diagnose glaucoma based on the overall assessment showed moderate agreement (Kappa [κ] statistic 0.55% and 95% confidence interval [CI]: 0.48-0.62). The use of FDT to detect glaucoma in the presence of disc damage (VCDR > 0.7) showed substantial agreement (κ statistic of 0.84 and 95% CI 0.79-0.90). A positive TG diagnosis of glaucoma carried a 77.5% positive predictive value, and a negative TG diagnosis carried an 82.2% negative predicative value relative to the clinical slit lamp examination. CONCLUSION: There was moderate agreement between the ability to diagnose glaucoma using TG relative to clinical slit lamp examination. Poor quality photographs can severely limit the ability of TG assessment to diagnose optic nerve damage and glaucoma. Although further work and validation is needed, the TG approach provides a novel, and promising method to diagnose glaucoma, a major cause of ocular morbidity throughout the world.