Post-cataract Surgery IOP Spike Increases Glaucoma Risk

Patients who undergo cataract surgery may have potential IOP spikes, which could lead to POAG. Even though they might not have a history of glaucoma, higher IOP cases will have an increased risk to develop the condition. Photo: Michael Chaglasian, OD. Click image to enlarge. The Academy of Ophthalmology’s IRIS Registry is one of the world’s leading databases for comprehensive eye diseases, which makes it a practical resource for studies in need of a large record of information on glaucoma, cataract, dry eye disease and other conditions. In a recent study, researchers from the University of Washington used the registry to determine how much of an increase of developing primary open-angle glaucoma (POAG) would occur after changes to intraocular pressure (IOP) following cataract surgery.“Our study investigated the potential impact of postoperative IOP elevation in patients without a history of glaucoma, while previous studies have focused on patients with a history of glaucoma,” wrote the authors in their paper published in Ophthalmology Science. It’s well documented that patients with initial glaucoma diagnoses are more likely to have higher IOPs after cataract procedures. In order to avoid repetitive results, the researchers focused on different subjects with no history of glaucoma, suspected glaucoma or ocular hypertension. They identified 1,912,101 subjects within the registry who matched the criteria and had undergone cataract surgery.First, the researchers divided subjects’ data into two groups: normal IOP (≤21mm Hg) and high IOP (>21mm Hg). Normal IOP subjects made up the majority of the population (78.7%) and high IOP subjects represented a minority (21.3%). Then, subjects who developed POAG were identified. Within the follow-up period of 4,000 days (~11 years), 10,710 subjects developed POAG with a median time to diagnosis of 682 days.Following an assessment of the data, the researchers determined the probability of developing POAG and the demographics that coincide with the disease. The probability of developing POAG for high IOP subjects was 3.4%, which was greater than the probability reported by normal IOP subjects (1.7%). Male subjects from either Asian, Black, Native Hawaiian and Other Pacific Islander backgrounds were at the highest risk of diagnosis. Notably, Black patients were at the highest risk, with results three times higher than white individuals. Additionally, Hispanic or Latino ethnicity was associated with a higher risk as well. Furthermore, older individuals, particularly patients 80 years and older, were also at a higher risk.The researchers then did a more granular analysis to understand how IOP ranges affected the risk of POAG. They included multiple categories spanning from ≤12mm Hg to >25mm Hg. Using hazard ratios (HR), they were able to figure out which categories were truly at a higher risk of developing POAG. For context, an HR of 1.00 is baseline. Beyond 1.00 means that the risk is increasingly becoming worse. In this study, a growing trend in HR was reported as IOP increased by category. The highest resulted in an HR of 2.42, while the lowest resulted in an HR of 0.88.“High postoperative IOP following cataract surgery was associated with a nearly double risk of glaucoma development among patients without a prior history of glaucoma, glaucoma suspect or ocular hypertension diagnoses, independent of demographic factors,” concluded the authors. “Such patients should be monitored more closely following cataract surgery for the future development of glaucoma.”Click here for the journal source. Gim N, Jiang Y, Bagdasarova Y, et al. Elevated intraocular pressure immediately after cataract surgery and future risk of primary open-angle glaucoma in the IRIS Registry (Intelligent Research in Sight). Ophthalm Sci. June 11, 2025. [Epub ahead of print].