Order of IOP measurement affects results

Intraocular pressure (IOP) is higher in the first eye that is measured, according to research published in Archives of Ophthalmology.

Dr Melike Pekmezci et al., Department of Ophthalmology, University of California, San Francisco, USA, conducted a study on 105 healthy participants who were randomized into 2 groups. Group 1 underwent 3 sets of 2 IOP measurements for each eye, starting with the right eye. The order of measurements was reversed for group 2. To determine the association of IOP measurement with the order measured a mixed-model, repeated-measures analysis of variance was used. This involved measurement between the first and second eyes, between the first and second visits, between the right and left eyes and with ocular squeezing.

Overall, measurements of IOP decline between first and second visits. IOP measurements were always higher in the initial eye measured, regardless of whether the right or left eye was measured first.

The results suggested that higher IOP measurements was linked to moderate and severe ocular squeezing. It is advised that multiple IOP measurements at multiple visits are crucial in the accurate diagnosis of glaucoma and ocular hypertension patients.