Peak IOP a better predictor of visual field progression than mean pressure or fluctuation

Arch Ophthalmol. 2011;129(5):562-568.

IOP-dependent and IOP-independent risk factors affect visual field progression in patients treated for glaucoma, with peak IOP showing a stronger correlation than mean IOP or pressure fluctuation, a study found.

Using a cohort of the Glaucoma Progression Study, the retrospective trial evaluated data from 587 eyes of 587 patients and used automated pointwise linear regression to assess visual field progression. Mean number of visual field tests was 11.1 over a mean period of 6.4 years.

Univariable analysis showed older age, baseline diagnosis of exfoliation syndrome, decreased central corneal thickness, a detected disc hemorrhage, presence of beta-zone parapapillary atrophy, and IOP parameters including mean, peak and pressure fluctuation to be associated with an increased risk for visual field progression.

A multivariable model showed peak IOP, decreased central corneal thickness, disc hemorrhage and presence of beta-zone parapapillary atrophy to be associated with progression.

Among IOP parameters, mean and peak IOP showed the strongest correlation, suggesting that higher mean IOP during follow-up may be associated with higher peaks, the study authors wrote.

"One advantage of using peak IOP in clinical practice is its ease of assessment because of its intrinsic relationship to target IOP," they wrote. "Peak IOP can be reassessed at each visit, whereas mean IOP determination requires longitudinal data collection and may be affected by the interval between visits."