Predictive value of tonometry with Tono-pen XL in primary care.

This is a descriptive study designed to assess the predictive value of intraocular pressure (IOP) measurement in GPs' offices in an urban healthcare site using Tono-pen XL. A total of 2044 patients, aged > or =40 years, were enrolled by consecutive sampling from patients visiting the GP. Those participants who had IOP > or =21 mmHg were referred to the ophthalmologist.