German Study Provides Insight to Prevalence

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German Study Provides Insight to Prevalence

Originally published in August 2023 Update

The Gutenberg Health Study (GHS) is a long-term, population-based investigation following more than 12,000 adults living in the Rhine Valley. The study was developed at the Johannes Gutenberg-University of Mainz to learn more about age-related diseases and to promote healthy living. To that end, scientific papers using data from the GHS have been published in the areas of cardiovascular disease, brain activity, and cancer. Information about eye diseases like age-related macular degeneration and glaucoma have also been published using GHS data.

Beginning in 2007 residents living in Mainz and the surrounding rural area invited to participate were given a battery of medical and psychological tests, including a comprehensive eye exam with Scheimpflug imaging (tomography). 10,419 subjects between the age of 35 and 74 were enrolled. Follow-up testing was performed in 2012 and 2017 on study participants, now aged 45 to 84.

Reviewing corneal tomography data, researchers diagnosed keratoconus in 75 eyes (51 individuals). The prevalence of disease was found to be 1:204, ten times higher than the often-quoted statistic of 1 in 2,000. The 1:2,000 is based on a population study conducted in Wisconsin in the 1930s. At that time, keratoconus was diagnosed by observing clinical signs of disease, and many mild or subtle cases went undetected.

Most large-scale prevalence studies use registry data or insurance information rather than actual patient exams. The results of this study are also remarkable because the study enrolled a large cross-section of area residents.

One weakness in this study is that it is unknown how many subjects found to have keratoconus were previously aware of their disease. It might have been helpful to learn how many cases had been undiagnosed and untreated. Also, no information was collected on disease progression. However, since all study subjects were seniors, it is unlikely substantial disease progression took place.

This study adds to the reality that keratoconus is not a rare disease – the prevalence of keratoconus is much higher than is commonly believed. Screening for keratoconus should become part of a comprehensive eye exam.

Reference: MuchhigherprevalenceofkeratoconusthanannouncedresultsoftheGutenbergHealthStudy,Marx-GrossS,FiessA,MunzelT,etal, Graefes Arch Clin Exp Ophthalmol, June 14:1-4, 2023. Online ahead of print.