Purpose
Choroidal neovascularization (CNV) is the most common vision-threatening complication associated with pathologic myopia (PM), also known as myopic CNV (mCNV). There is a lack of information on the epidemiology related to mCNV in the world and more so in Canada. This study aimed to determine the epidemiology and the demographic and treatment characteristics of Canadian mCNV patients.
Methods
Records from a longitudinal population-based database of more than 320,000 patients, collected from 75 physicians in Southwestern Ontario, Canada were analyzed between January 1, 2006 and December 31, 2011. Patient records were limited to subjects aged 18 years and older, and patients with at least one year of follow up. The clinical and demographics characteristics, comorbidity, medications, and resource use were reported in this study. A nested case-control study based on the final diagnosis of CNV secondary to PM was constructed within a PM cohort. In this study, 211 patients with mCNV were matched for demographic characteristics with 211 PM controls.
Results
The prevalence of CNV secondary to PM was estimated to be 0.084% in the general adult population with an annual incidence of 0.0061%. Amongst PM patients, 6.2% develop CNV. Ten percent (10%) of patients had both eyes affected with CNV. CNV was mostly subfoveal (87%) and was more common in women than men. At the time of CNV diagnosis, the mean Snellen score was 20/100 in the affected eye. The most common treatments were verteporfin and laser photocoagulation. Approximately 23% of mCNV patients had hypertension. The burden of resource use, including emergency visits, general practitioners clinic visits, ophthalmology visits, and hospitalizations is more important in mCNV patients than in PM patients (p<0.01).
Conclusions
In a Canadian real-world setting, the prevalence and the annual incidence of myopic CNV was 0.084% and 0.0061%, respectively. This is the first Canadian study investigating the epidemiology of myopic CNV and the results will help us better understand this debilitating disease.
Keywords: 453 choroid: neovascularization •
463 clinical (human) or epidemiologic studies: prevalence/incidence