Evaluating the Incidence of Arteritic Ischemic Optic Neuropathy and Other Causes of Vision Loss from Giant Cell Arteritis.

To determine the incidence of permanent visual loss from giant cell arteritis (GCA).,Retrospective, population-based cohort.,All residents of Olmsted County, Minnesota, diagnosed with GCA between January 1, 1950, and December 31, 2009.,All cases of GCA were identified using the Rochester Epidemiology Project (REP), which is a record-linkage system of medical records for all patient-physician encounters among Olmsted County, Minnesota, residents. The medical records were reviewed to identify and determine the cause of permanent vision loss among patients with GCA. Systemic symptoms of GCA and visual outcomes also were determined.,Incidence and outcomes of permanent vision loss from GCA.,Among the 245 new cases of GCA over the 60-year period, 20 patients (8.2%) had permanent vision loss due to GCA. The frequency of arteritic ischemic optic neuropathy (A-ION) was 6.9% (95% confidence interval [CI], 4.0-11.1) accounting for 85% of cases of permanent vision loss. The frequency of central retinal artery occlusion (CRAO) was 1.6% (95% CI, 0.4-4.2), and the frequency of cilioretinal artery occlusion was 0.4% (95% CI, 0.01-2.3). The population-based age- and sex-adjusted annual incidence of A-ION from GCA among persons aged ≥50 years was 1.3 (95% CI, 0.7-2.0) per 100 000 population. Some 20% of patients with permanent vision loss from GCA had vision loss without constitutional symptoms of GCA. Overall, there was no significant difference between presenting and final visual acuities.,These population-based data provide the most accurate incidence of permanent vision loss from GCA. This study confirms that visual outcomes from GCA-related vision loss are poor and that 20% of patients with permanent visual loss from GCA can present without systemic symptoms of GCA.