Ocular Hypertension Treatment Study (OHTS) Calculator

About the ocular hypertension treatment study

OHTS is a clinical decision making instrument that helps identify patients aged 30-80 years old, with ocular hypertension, who may benefit from therapy to lower intraocular pressure and reduce the risk of progression to glaucoma.

In the United States, 3 to 6 million people are at an increased risk of developing primary open-angle glaucoma (POAG) due to elevated intraocular pressure (IOP), or ocular hypertension.

This POAG risk prediction method is 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.

OHTS is not validated for use in patients under 30 or over 80 years of age. Another limitation is that it has little utility in later stages of glaucoma.

Patients with possible secondary causes of elevated intraocular pressure (IOP), such as pigment dispersion or pseudoexfoliation, should be excluded, along with those who have visual field loss due to non-glaucomatous conditions.

Scoring the OHTS

The final OHTS score is calculated by adding the individual points and is then directly correlated to a 5 year risk of developing primary open-angle glaucoma (POAG) and a treatment recommendation.

About the original study and further validation

The 2002 original study by Kass et al. consisted of a randomized controlled trial that evaluated 1,636 patients with ocular hypertension without glaucomatous field or optic nerve loss and found that lowering IOP was beneficial in preventing the progression to glaucoma.

The study also identified several clinical characteristics that predict onset of POAG. During the course of the study, there was little evidence of increased systemic or ocular risk associated with ocular hypotensive medication.

Topical ocular hypotensive medication proved effective in delaying or preventing the onset of primary open-angle glaucoma (POAG) in individuals with elevated intraocular pressure (IOP). While this does not suggest that all patients with borderline or elevated IOP should be treated, clinicians should consider starting treatment for those with ocular hypertension who are at moderate to high risk of developing POAG.

In 2007, the OHTS prediction model was validated using the placebo group from the EGPS study. A risk calculator, based on the combined OHTS-EGPS predictive model, provides highly accurate estimates of the 5-year risk of developing POAG.

This tool demonstrated that it could assist clinicians and patients in determining the appropriate frequency of tests and follow-up examinations, as well as the advisability of starting preventive treatment.

References

Original reference

Kass MA, Heuer DK, Higginbotham EJ, Johnson CA, Keltner JL, Miller JP, Parrish RK 2nd, Wilson MR, Gordon MO. The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma. Arch Ophthalmol. 2002; 120(6):701-13; discussion 829-30.

Validation

Ocular Hypertension Treatment Study Group; European Glaucoma Prevention Study Group; Gordon MO, Torri V, Miglior S, Beiser JA, Floriani I, Miller JP, Gao F, Adamsons I, Poli D, D'Agostino RB, Kass MA. Validated prediction model for the development of primary open-angle glaucoma in individuals with ocular hypertension. Ophthalmology. 2007; 114(1):10-9.

Other references

Gordon MO, Beiser JA, Brandt JD, Heuer DK, Higginbotham EJ, Johnson CA, Keltner JL, Miller JP, Parrish RK 2nd, Wilson MR, Kass MA. The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma. Arch Ophthalmol. 2002; 120(6):714-20; discussion 829-30.

Ocular Hypertension Treatment Study Group and the European Glaucoma Prevention Study Group. The accuracy and clinical application of predictive models for primary open-angle glaucoma in ocular hypertensive individuals. Ophthalmology. 2008; 115(11):2030-6.