The calculator tested in this study was able to reliably identify which patients had glaucoma. Photo: James Fanelli, OD. Click image to enlarge.

Glaucoma is a leading cause of preventable blindness globally, but nearly half of affected patients in the United States are undiagnosed. The risk of progressive and irreversible loss of vision is decreased with an early diagnosis, and better access to treatment is vital to improved visual outcomes. With this in mind, researchers recently suggested that a minimally invasive, low-cost calculator used to predict the risk of glaucoma and inform the course of follow-up care could help improve patient prognosis.

“To our knowledge, our report represents the first attempt to generate an affordable screening calculator to identify patients with glaucoma or those at high risk for glaucoma based on three risk factors without the need for a comprehensive ophthalmic exam, fundus exam and visual field testing,” they wrote in their paper.

The investigators retrospectively examined data from 104 eyes (54 with glaucoma and 50 controls) of patients who underwent a complete ocular examination, visual field testing and corneal pachymetry. They evaluated the discriminatory power of the Laroche glaucoma calculator, a novel tool that combines age, intraocular pressure (IOP) and central corneal thickness (CCT) into a composite metric. With a range of -3 to 18, a score of ≥6 on the calculator (sensitivity: 90.7%, specificity: 64.0%, correct classification: 77.9%) optimizes the accuracy of this tool.

Compared with IOP and CCT measurements alone, the Laroche glaucoma calculator was significantly better when it came to discriminating between glaucoma patients and healthy controls.

“This calculator is very promising for screening particularly in resource-poor areas and to provide cost-effective glaucoma screenings by trained nonphysician allied health professionals,” the team concluded in their paper. “Our prediction model demonstrated excellent discrimination in identifying patients with glaucoma with optic nerve damage and visual field loss, as well as those at high risk for glaucoma.”

The researchers noted that future studies are necessary to further validate this new glaucoma calculator.