Glaucoma patients need more aggressive IOP targets than those commonly used in practice, a large study finds. Investigators recently compared rates of progressive RNFL loss with three IOP targets: 18mm Hg as advocated by the AGIS study, but also stricter and looser cutoffs of 15mm Hg and 21mm Hg, respectively. The study focused on the real-world impacts of IOP control on rates of change of RNFL thickness.
The retrospective cohort study identified 85,835 IOP measurements with Goldmann applanation tonometry and 60,223 good-quality SD-OCT tests from 14,790 eyes of 7,844 patients in the Duke Glaucoma Registry. Eyes had a mean follow-up of 3.5±1.9 years. The average rate of change in RNFL thickness was -0.68±0.59μm/year.
Eyes were classified as slow, moderate and fast progressors if change was slower than -1μm/year, between -1 and -2μm/year and faster than -2μm/year, respectively. The researchers found that each incremental 1mm Hg gain in mean IOP was associated with a 0.05μm/year faster RNFL loss.
Looking at characteristics of fast progressors specifically, 41% had IOP below 21mm Hg in all visits during follow-up, whereas 20% were below 18mm Hg and 9% were under 15mm Hg. “These results suggest that a target IOP of 15mm Hg would make it much less likely to have fast progression, while a target of 21mm Hg would still be insufficient for a large number of eyes in preventing fast deterioration,” the team explained in their publication.
The researchers concluded that IOP was significantly associated with rates of progressive RNFL loss in a real-world, large clinical population. “By investigating the relationship between the frequency of visits with IOP below certain cutoff levels and the risk for fast progression, our findings may assist clinicians in establishing target pressures in clinical practices,” they noted in their paper.
Jammal AA, Thompson AC, Mariottoni EB, et al. Real-world impact of intraocular pressure control on rates of retinal nerve fiber layer loss in a large clinical population. Ophtahlmol. June 20, 2020. [Epub ahead of print].