Glaucoma Examination in the Amish of Holmes County, Ohio

Abstract

Purpose : Despite extensive efforts to understand the genetic and environmental risk factors for glaucoma, we still do not have a full clinically useful profile for any of the major types of glaucoma. We have previously established a significant presence of glaucoma in the Amish in Holmes County OH. Our goal was to determine the prevalent type(s) of glaucoma present in this population and begin assessing for unique genetic and environmental risk factors. The Amish in Holmes County, Ohio, are a unique population that provides a truly unmatched opportunity to study complex diseases on a more homogeneous genetic and environmental background.

Methods : Amish subjects who were identified through an existing research infrastructure as likely having glaucoma were screened by a glaucoma specialist via a comprehensive ophthalmic examination. Glaucoma type and severity were determined. Extensive familial structure and relatedness data was reviewed. Lifestyle questionnaires and interviews were used to assess environmental exposures and habits. Blood drawn from subjects will be utilized for comprehensive genetic analysis.

Results : 19 of the Amish subjects identified as likely having glaucoma as above have thus far been screened for glaucoma. 16/19 were determined to have primary open angle glaucoma (POAG), ranging in severity from suspect to severe. Lifestyle assessment has confirmed a more homogeneous and reduced exposure to typical western society risk factors such as to alcohol and smoking. An additional 100+ subject with likely glaucoma in this population will be recruited, many of whom show familial clustering.

Conclusions : We determined that heritable glaucoma is present in the Amish of Holmes County, Ohio and is predominately POAG. Improved, consistent phenotyping and comprehensive genetic/environmental interaction studies are key to identifying and understanding the complex interplay between glaucoma risk factors. Accessing an extensive and largely related Amish population to understand risk factors of heritable adult-onset glaucoma has not previously been reported, and offers the opportunity to identify novel genetic and environmental risk factors. The Amish are ideal for these studies due to a relatively homogeneous genetic background and a less diverse and shared environmental exposure profile. Characterizing glaucoma in this group offers the potential for a great deal of insight into this high-impact complex disease.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.