Prevalence of Glaucoma in Canada: Results from the Canadian Health Measures Survey between 2016 and 2019

Theme: Glaucoma
What: Glaucoma
Part of: Glaucoma III: Old is New / Glaucome III: Faire du neuf avec du vieux
When: 5/31/2024, 04:15 PM - 05:45 PM
Where: Room | Salle 801

Abstract

Purpose: To estimate the prevalence of glaucoma in Canada between 2016 and 2019 based on data derived from the Canadian Health Measures Survey utilizing Frequency Doubling Technology Perimetry (FDT), vertical cup-to-disc ratio (CDR), and intraocular pressure (IOP).

Study Design: Cross-sectional survey.

Methods: Data was examined from 2,612 randomly selected Canadians aged 40-79 taking part in the Canadian Health Measures Survey between 2016 and 2019. Following questions regarding a history of glaucoma, participants were invited to a mobile clinic for an ocular examination, including FDT, fundus photographs, and IOP. Participants who failed FDT and had a CDR≥0.7, with or without raised IOP, were considered to have examination-determined definite glaucoma. Those with FDT failed only, CDR≥0.7 only or IOP>21 mmHg only, or those with ‘normal’ values of FDT, CDR, and IOP but used glaucoma medications, were considered glaucoma suspects. Participants who passed FDT, had CDR<0.7, IOP≤21 mmHg, and did not use glaucoma medications were deemed as not having glaucoma.

Results: Based on self-reports, an estimate of 421,800 Canadians aged 40-79 had glaucoma, representing a prevalence of 2.5% (95% confidence interval [CI] 1.7%-3.3%). The prevalence was higher in Canadians aged 65-79 (5.0%) than those aged 40-64 (1.6%), in people with less than secondary school graduation (5.0%) than those with secondary school graduation (2.0%) or higher (2.3%), and in individuals who had visited an ophthalmologist/optometrist in the past 12 months (10.0%) versus those that did not (1.4%). Less than half (44.0%) of the self-reported glaucoma individuals used glaucoma medications.

Based on ocular examination, there were 71,000 Canadians with definite glaucoma and an additional 1.7 million Canadians labelled as glaucoma suspects. Corresponding prevalence was 0.7% (95% CI 0.3%-1.1%) and 16.3% (95% CI 13.2%-19.4%), respectively.

Of the glaucoma suspects, 44.3% had ocular hypertension (OHT, mean IOP 22.8 mmHg). Only 3% of OHT individuals used glaucoma medications. IOP≥28 mmHg was found in 2.4% of OHT individuals, with a mean of 31.0 mmHg. None of the individuals with IOP≥28 mmHg was on glaucoma medications.

Nearly 2/5 (37.5%, or 26,625) of Canadians with examination-determined definite glaucoma were unaware they had glaucoma.

Conclusions: Amongst Canadians aged 40-79, the prevalence of glaucoma was 2.5% based on self-reports and 0.7% based on clinical examination. Examination identified 1/6 Canadians as glaucoma suspects requiring further examination to clarify a glaucoma diagnosis. Few Canadians with OHT used glaucoma medications, including those with IOP≥28 mmHg. Nearly 2/5 Canadians with examination-determined definite glaucoma were unaware of their disease status.

Presenter(s)

Presenting Author: Qingqing Kinna Zhao*

Additional Author(s):

Ziad Butty*, Department of Ophthalmology and Vision Sciences, University of Toronto

Kiko Zi Yi Huang, Institute of Medical Science, University of Toronto

Graham E. Trope, Department of Ophthalmology and Vision Sciences, University of Toronto

Yvonne M. Buys, Department of Ophthalmology and Vision Sciences, University of Toronto

Ya-Ping Jin, Dalla Lana School of Public Health, Department of Ophthalmology and Vision Sciences, University of Toronto

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