Please visit the OHTS main website for the Risk Calculator.

Based on Results from the Ocular Hypertension Treatment Study (OHTS) and the European Glaucoma Prevention Study (EGPS), we present a method for estimating the 5-year risk that an individual with ocular hypertension will develop Primary Open Angle Glaucoma (POAG).

The method may be useful to clinicians and patients in deciding the frequency of tests and examinations and the potential benefit of starting treatment.

More information is available in the manuscript, “A Validated Prediction Model for the Development of Primary Open Angle Glaucoma in Individuals with Ocular Hypertension,” published in Ophthalmology 2007; 114(1):10-19.

Directions for use

The prediction models for POAG require the following information:

  • Age
  • Vertical cup/disc ratio by contour
  • IOP (3 measurements per eye measured using Goldmann applanation tonometry)
  • Central corneal thickness using an ultrasound pachymeter (3 measurements per eye)
  • Pattern standard deviation using any of the following (2 measurements per eye):
    1. Humphrey full threshold 30-2 or 24-2
    2.  SITA standard 30-2 or 24-2
    3. Loss variance from Octopus 32-2


Two methods can be used to estimate the 5-year risk of developing POAG: A continuous method based on actual data and a simplified point system. Please read the limitations and cautions listed below.

  • For the Continuous Method you will enter actual data for the patient age and eye measurements.
  • For the Point System you will select the range for the patient age and average of the multiple measurements.
  • Your results in using the two methods will be similar but not identical. Please view the examples for each method listed below.