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.

Use Continuous Method (pdf)

Use Points System (pdf)

Limitations and cautions

  • The prediction methods presented here are derived from two studies (OHTS and EGPS) and should be useful to clinicians and patients. There is no guarantee that the predicted risk is accurate for individual patients.

  • The predictions are more likely to be accurate for patients who are similar to the participants studied in the OHTS and the EGPS, and if the testing protocols for your patients resemble those used in these studies.

  • These prediction models were derived from studies on the development of early POAG. It is not clear whether these models also predict progression of established disease or the development of visual disability.

  • The following types of participants and methods of measurement were utilized in the OHTS and the EGPS:

    • Age: Age between 30 and 80 years. A warning will be issued for ages greater than 80 or less than 30.
    • Untreated IOP: IOP range 20-32 mm Hg. This is based on three measurements per eye, both eyes, measured using Goldmann applanation tonometry. A warning will be issued for values outside 20-32 mm Hg.
    • Central Corneal Thickness (CCT): CCT 475-650 microns. Three measurements per eye, both eyes, measured using ultrasonic pachymetry. A warning will be issued for values outside 475-650 microns.
    • Vertical cup to disc ratio: One measurement per eye, both eyes. C/D ratio vertically by contour, not by color.
    • Pattern standard deviation/corrected loss variance: Two measurements per eye, both eyes, measured using either Humphrey or Octopus perimeters. Octopus Corrected Loss Variance measurements will be converted internally to Humphrey PSD equivalent.
The predictions derived using these methods are designed to aid but not to replace clinical judgment.

Copyright: Washington University 2006. Risk estimators accessible on this website are offered for use to direct users of this website only. Direct users may choose to use the estimators online or download the estimators to their own electronic devices for future personal use. Estimators may not be otherwise downloaded or redistributed without permission from the Vision Research Coordinating Center at Washington University.