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Purpose: Histological evidence indicates that the earliest structural changes to the optic nerve head (ONH) in glaucoma occur in the lamina cribrosa (LC) and its interface with the sclera. However, clinical imaging of these structures remains challenging. We compared the visibility of deep ONH structures with newer iterations of spectral-domain (SD) and swept-source (SS) optical coherence tomography (OCT)., Methods: Twelve patients with open-angle glaucoma were imaged with SD-OCT with 24 radial B-scans centred on Bruch's membrane opening (BMO) and SS-OCT with a horizontal and vertical raster scan pattern containing five lines each, centred on the ONH. Single best-matched horizontal and vertical scans from the two modalities were selected and exported. Three independent observers masked to modality determined if BMO, posterior choroid surface, anterior scleral canal opening and anterior and posterior LC insertions into the sclera were detectable in the matched B-scan images. We determined the interobserver agreement and concordance in detecting each structure with the two OCT imaging modalities., Results: There was a high interobserver agreement with both SS-OCT and SD-OCT (inter-item correlations: 0.81-0.93 and 0.77-0.82, respectively). There was a consistent tendency for higher overall detection rates with SS-OCT, however, the differences failed to reach statistical significance. With respect to individual structures, only the posterior LC insertion in the nasal quadrant was statistically different, with a detection rate of 13 and 6 (pooled out of a total of 36 across the three observers) with SS-OCT and SD-OCT, respectively (p=0.04)., Conclusion: Overall, both SS-OCT and SD-OCT showed statistically equivalent visualisation of ONH structures, however, SS-OCT tended to have higher visualisation rates., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Ocular surface squamous neoplasia (OSSN) is the most common non-pigmented ocular surface malignancy. It is classified as invasive OSNN (IOSSN) when the underlying stroma are infiltrated by dysplastic squamous epithelial cells through the basement membrane. Here, we present the descriptive epidemiology and geographical distribution of IOSSN in Canada., Methods: We determined the incidence and geographical distribution of IOSSN cases diagnosed between 1992 and 2010 using two independent population-based cancer registries: the Canadian Cancer Registry and Le Registre Québécois du Cancer., Results: The mean annual age-standardised incidence rate (WHO 2000-2025) of IOSSN for 1992-2010 was 0.45 cases per million individuals per year with an average annual percent increase in incidence of 4.5%. IOSSN localisation to the conjunctiva was documented in at least 57% of the reported cases. IOSSN exhibited a male predilection ratio of 3.3:1.0 with a mean age at diagnosis of 69 years. Incidence rates of IOSSN across Canadian provinces and cities showed no significant differences from the crude national average., Conclusions: Our results, particularly concerning IOSSN patient age and male predilection, corroborate with data reported from the USA. Additional studies are needed to determine whether the observed increase in incidence rate over the study period (1992-2010) is significant., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Ophthalmic lymphoma (OL) is the most common orbital tumour, particularly in older individuals. Little is known about the epidemiology and geographic distribution of OL in Canada. Descriptive demographic statistics are an important first step in understanding OL burden and are necessary to inform comprehensive national cancer prevention programmes., Methods: We determined patterns of incidence and geographical distribution of the three major subtypes of OL: extranodal marginal zone B cell lymphoma, follicular lymphoma (FL) and diffuse large B cell lymphoma. Here, we used cases that were diagnosed during 1992-2010 using two independent population-based cancer registries, the Canadian Cancer Registry and Le Registre Québécois du Cancer (LRQC)., Results: The OL mean annual age-standardised incidence rate for 1992-2010 was 0.65 cases per million people per year with an average annual increase in the incidence rate of 4.5% per year. The mean age of diagnosis was 65 years. OL incidence rate was the highest in the cities located along the heavily industrialised Strait of Georgia in British Columbia., Conclusions: Our data on patient age, sex and temporal trends showed similarities with data reported in the USA and Denmark. Additional studies are needed to determine whether the observed increase in OL incidence is genuine or spurious., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Melanoma is the most common primary malignancy of the eye in adults. While the epidemiology of uveal melanoma has recently been described in Canada, little is known about the epidemiology and geographic distribution of patients with conjunctival melanoma (CM) in Canada., Methods: We conducted a population-based study of CM incidence across all Canadian provinces and territories during 1992-2010 using two independent population-based registries., Results: 190 patients were diagnosed with CM in Canada from 1992 to 2010. 55.3 % of these patients were men. The mean annual incidence rate of CM in Canada was 0.32 cases per million individuals (0.35 and 0.29 cases per million individuals for men and women, respectively). The incidence rates for Canadian provinces demonstrated that the eastern provinces of Nova Scotia and New Brunswick had higher age-adjusted incidence rates than the national average, with rates of 0.52 and 0.47 cases per million individuals per year, respectively., Conclusions: This analysis demonstrates novel variations in CM incidence rates between different Canadian provinces. These results taken together with the data reported from the USA confirm the North-to-South geographic gradient of increasing CM incidence. This research highlights that the epidemiology of CM in North America is comparable to that of cutaneous malignant melanoma in contrast to the trends for uveal melanoma distribution., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: In the developed countries, uveal melanoma is the most common primary intraocular malignancy in adults. Little is known about the epidemiological and geographical distribution of uveal melanoma in Canada., Methods: To determine the incidence patterns and geographical distribution of uveal melanoma cases in Canada, we conducted the first comprehensive, population-based national study of this malignancy across all Canadian provinces and territories during 1992-2010 years. We examined two independent population-based registries: the Canadian Cancer Registry and Le Registre Québécois du Cancer using corresponding International Classification of Diseases for Oncology-3rd edition codes for all histological subtypes of uveal melanoma., Results: We report that 2215 patients were diagnosed with uveal melanoma, of which 52.1% were males. The average -annual incidence rate of uveal melanoma in Canada was 3.75 cases per million individuals per year (95% CI 3.60 to 3.91). Overall, we report a steady increase in uveal melanoma incidence with an annual increase of 0.074 cases per million individuals per year. Significant differences in the incidence rates of uveal melanoma between Canadian provinces and territories were noted, where the highest crude incidence was in British Columbia and Saskatchewan with rates of 6.38 and 5.47 cases per million individuals per year, respectively., Conclusions: This work, for the first time, defines the disease burden of uveal melanoma in Canada and highlights important longitudinal, geographical and spatial differences in the distribution of uveal melanoma in Canada., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)