This study's findings showed that target IOP difference can help predict VF worsening. Photo: Brian Fisher, OD, David Johnson, OD, and April Fisher, OD. Click photo to enlarge.

Intraocular pressure (IOP) is the only risk factor that can be directly treated to reduce the chances of glaucoma progression. New research from Johns Hopkins reports that failing to achieve target IOP may lead to more rapid visual field (VF) worsening, with eyes with moderate glaucoma facing the greatest risk. Faster VF worsening was noted in eyes with higher readings above the target IOP.

The study enrolled 2,852 eyes of 1,688 patients with glaucoma-related diagnoses who were treated in a tertiary care practice. All eyes had at least five reliable VF tests and five IOP measures on separate visits, along with at least one target IOP defined by a clinician on the first or second visit.

Across all eyes, a 1mm Hg increase in target difference resulted in a -0.018 dB/year effect on mean deviation slope. A mixed effects model used in the study showed that eyes with moderate disease that failed to achieve target IOP experienced the largest effects, with a 1mm Hg increase in target difference resulting in a worse MD slope of 0.119dB/year.

The effects of missing the target IOP on VF worsening were much more pronounced compared with the effect of absolute level of IOP on VF worsening, where a 1mm Hg increase in IOP had a -0.004dB/year effect on the mean deviation slope.

Importantly, the clinicians included in this study, on average, followed published guidelines that suggested target IOPs be set in the high teens for eyes with mild disease, the mid-teens for moderate disease and the low teens for advanced disease.

“Thus, one may be able to generalize these results to clinicians following similar evidence-based guidelines,” the researchers wrote in their paper.

Based on the study’s results, the authors recommend using target IOP difference as a predictor of VF worsening. Target IOP can also be customized to the degree of damage and even beyond, they add.