Ocular Hypertension Treatment Study (OHTS) Calculator

OHTS 5-Year Glaucoma Risk

Age

years

Intraocular Pressure (IOP)

mmHg

Central Corneal Thickness (CCT)

µm

Vertical Cup/Disc Ratio

Pattern Standard Deviation (PSD)

Identifies patients that may benefit from therapy to lower intraocular pressure (IOP).

Why Use

Aids in shared decision making with patients regarding whether to initiate treatment for ocular hypertension based on the five-year risk of progression to open angle glaucoma.

When to Use

Use in an outpatient setting in patients 30-80 years old with ocular hypertension to assess need for initial treatment to reduce the likelihood of progression to glaucoma.

Formula

Addition of the selected points: Variable Points Age, years 30-44 0 45-54 1 55-64 2 65-74 3 ≥75 4 Mean intraocular pressure*, mmHg <22 0 22 to <24 1 24 to <26 2 26 to <28 3 ≥28 4 Mean central corneal thickness*, µm >600 0 576–600 1 551–575 2 526–550 3 ≤525 4 Mean vertical cup-to-disc ratio by contour <0.3 0 0.3 to <0.4 1 0.4 to <0.5 2 0.5 to <0.6 3 ≥0.6 4 Mean pattern standard deviation**, dB <1.8 0 1.8 to <2.0 1 2.0 to <2.4 2 2.4 to <2.8 3 ≥2.8 4 *Mean of three measurements per eye. **2 measurements per eye of: Humphrey full threshold 30-2, SITA Standard 30-2 or 24-2, or loss of variance from Octopus 32-2.

Pearls / Pitfalls

The original studies used patients with a baseline intraocular pressure (IOP) of 22 to 32 mmHg. Not validated in patients under 30 years of age or over 80 years of age. Primarily developed from studies looking at the early development of primary open angle glaucoma (POAG) and has little utility in later stages of glaucoma. Patients with potential secondary causes of elevated IOP including pigment dispersion or pseudoexfoliation should be excluded, as well as patients with non-glaucomatous reasons for visual field loss. There are other established risk factors for the development of POAG, and these should be taken into account separately.

Management

Initiation of IOP lowering therapy. Close monitoring with visual field and optic nerve head imaging every 3-12 months, depending on specific patient parameters.

Advice

Patients with a score between 0-6 can be observed every 6 months. Patients with a score between 7-12 should be counseled about the risks and benefits of starting treatment versus close observation. Patients with a score >12 should strongly consider initiating treatment.

More Information

Interpretation: OHTS Score 5 year risk of developing POAG Risk - Recommendation 0-6 ≤4.0% Low - Recommend observation every 6 months 7-8 10% Intermediate - Recommend counseling on risks/benefits of treatment versus close observation 9-10 15% 11-12 20% >12 ≥33% High - Recommend initiating treatment