New research has revealed that despite an evolving clinical understanding of glaucoma, many ophthalmologists continue to rely on the historical “normal” intraocular pressure (IOP) threshold of 22 mm Hg as a primary driver for treatment decisions.
The study, published in JAMA Ophthalmology this month, and titled ‘Influence of Intraocular Pressure on Clinical Decision-Making in Glaucoma Management’, analysed more than 1.86 million clinic encounters across seven US academic eye centres.
The data indicated that while clinicians generally treat IOP as a continuous risk factor, there was a noticeable increase in intervention at a specific point.
According to the findings led by Dr Ashley Polski of the John A. Moran Eye Center at the University of Utah:
- Clinicians were significantly more likely to initiate or increase therapy when a patient’s IOP reached 22 mm Hg.
- At this level, the odds of starting treatment increased by 23% (OR 1.23) compared with lower pressures.
- Treatment odds were lower for pressures of 19, 20, and 21 mm Hg.
The historical “normal” range of 10 to 21 mm Hg was established decades ago based on population averages. However, the study pointed out that current understanding acknowledges that glaucoma can occur with “normal” pressures, and some patients with “high” pressures may not develop damage.
The authors suggested that relying on this binary threshold might serve as a “decisional shortcut” to manage the complexity of clinical data.
The researchers proposed that these findings highlight the need for improved clinical decision support systems. Such tools could help clinicians move away from historical thresholds and focus on individualised “target” pressures based on various factors like optic nerve health, visual field testing, and family history.
The study concluded that clinicians should be aware of how cognitive limitations can lead to a reliance on “decisional shortcuts” that might bias decision-making.
“The future of glaucoma care is moving beyond fixed pressure cutoffs toward more individualised, risk-based treatment decisions that better reflect our understanding of the disease,” DrPolski said.
Dr Brian Stagg, a glaucoma specialist and public health researcher with Moran’s Alan S. Crandall Center for Glaucoma Innovation, said the findings pointed to a need for improved decision-support tools in clinic that can help the field go beyond heavy reliance on a threshold number.
“Improved decision-support tools can aggregate patient data to help physicians better use continuous eye pressure and other factors to inform treatment, rather than relying on a single cutoff number,” he said.
