Probability of filtration surgery in patients with open-angle glaucoma.

OBJECTIVE: To investigate the probability of undergoing filtration surgery in either 1 or both eyes in patients in whom open-angle glaucoma was newly diagnosed. METHODS AND DESIGN: A retrospective community-based study of 295 residents of Olmsted County, Minnesota, in whom open-angle glaucoma was newly diagnosed between January 1, 1965, and December 31, 1980, was performed. Kaplan-Meier methods were used to estimate the cumulative probability of undergoing filtration surgery during a 20-year period. RESULTS: At 20 years of follow-up, the Kaplan-Meier cumulative probability of undergoing filtration surgery in at least 1 eye was estimated to be 23% (95% confidence interval, 16%-30%), and in both eyes the estimate was 12% (95% confidence interval, 6%-17%). Patients with optic nerve damage at the time of diagnosis were more likely to undergo surgery than patients with elevated intraocular pressure but no damage (1 eye, 39% vs 15%; both eyes, 27% vs 5%). CONCLUSION: This retrospective study of a white population newly diagnosed as having and treated for open-angle glaucoma indicates that while most patients did not undergo filtration surgery in the course of glaucoma therapy, at least one third of those with glaucomatous damage at the time of diagnosis underwent filtration surgery.

The probability of blindness from open-angle glaucoma.

OBJECTIVE: This study aimed to determine the probability of a patient developing legal blindness in either one or both eyes from newly diagnosed and treated open-angle glaucoma (OAG) after starting medical or surgical therapy or both. DESIGN: The study design was a retrospective, community-based descriptive study. PARTICIPANTS: Two hundred ninety-five residents of Olmsted County, Minnesota, newly diagnosed with, and treated for, OAG between 1965 and 1980 with a mean follow-up of 15 years (standard deviation +/- 8 years) participated. INTERVENTION: Kaplan-Meier cumulative probability of blindness was estimated for patients treated and followed for OAG. MAIN OUTCOME MEASURES: Legal blindness, defined as a corrected visual acuity of 20/200 or worse, and/or visual field constricted to 20 degrees or less in its widest diameter with the Goldmann 1114e test object or its equivalent on automated perimetry, secondary to glaucomatous loss, was measured. RESULTS: At 20-years' follow-up, the Kaplan-Meier cumulative probability of glaucoma-related blindness in at least one eye was estimated to be 27% (95% confidence interval, 20%-33%), and for both eyes, it was estimated to be 9% (95% confidence interval, 5%-14%). At the time of diagnosis, 15 patients were blind in at least 1 eye from OAG. CONCLUSION: A retrospective study of a white population determined that the risk of blindness from newly diagnosed and treated OAG may be considerable.

Cataract extraction rates in Olmsted County, Minnesota, 1980 through 1994.

OBJECTIVE: To analyze population-based trends in cataract extraction. DESIGN: Rochester Epidemiology Project databases; which capture virtually all health care services provided to residents of Olmsted County, Minnesota, were used to perform retrospective cohort analyses of rates of primary cataract extractions performed between 1980 and 1994. PARTICIPANTS: The population of Olmsted County, Minnesota. MAIN OUTCOME MEASURES: Incidence rates adjusted to the age and sex distribution of the 1990 US white population were analyzed using Poisson regression. RESULTS: The 4257 procedures performed on 3176 patients of all ages represented overall annual age-adjusted rates of 404 procedures per 100,000 females and 320 per 100,000 males. Annual age- and sex-adjusted rates for both sexes combined rose from 133 procedures per 100,000 in 1980 to a peak of 507 per 100,000 in 1992. The rates fell to 470 per 100,000 in 1994. Manual review of a random sample of records estimated case overascertainment at 0.9%. CONCLUSIONS: With the exception of 1988 and 1989, rates of cataract surgery in this geographically circumscribed population increased every year between 1980 and 1992. Data from 1993-1994 indicate that rates may have plateaued and possibly declined slightly. If sustained, these patterns could have major implications for future utilization of ophthalmologic resources.

Concordance of Medicare data and population-based clinical data on cataract surgery utilization in Olmsted County, Minnesota.

The authors assessed concordance of local Medicare health care utilization data on cataract surgery and estimates generated using the databases of the Rochester Epidemiology Project, which capture virtually all medical care received by residents of Olmsted County, Minnesota. The Rochester Project databases identified 1,353 primary cataract extractions performed in Olmsted County between October 1989 and December 1993 among county residents aged > or = 65 years. Medicare data identified 1,148 claims-84.8% of the number of procedures identified by the Rochester Project. Ratios of numbers of encounters (Medicare/Rochester Project) were 189/350 (0.540) for 1992 versus 959/1,003 (0.956) for the other years combined. Changes in Medicare data file transfer procedures may have produced the 1992 data shortfall. Medicare data should periodically be compared with source data to assess concordance.