Determinants of post-mydriatic intraocular pressure in phakic eyes with prevalent angle closure diseases

This study aimed to identify acute angle closure (AAC) risk following pharmacologic mydriasis and the factors affecting post-mydriatic intraocular pressure (IOP) in a population with a high prevalence of angle closure disease.

In total, 460 individuals aged ≥ 72 years were enrolled in this cross-sectional community-based screening program. IOP was measured at baseline and 1 hour after mydriasis. Individuals with post-mydriatic IOP spike > 6 mmHg received indentation gonioscopy and IOP-lowering medication. Linear regression analysis was used to identify ocular parameters associated with post-mydriatic IOP elevation.

The mean age of participants was 77.8 ± 4.1 years, and 65.4% of them were men. In total, 21 eyes of 16 participants (3.48%) had post-mydriatic IOP spikes (range: 6-13.7 mmHg); among them, 15 eyes had an IOP of > 21 mmHg. None of the participants developed AAC. All eyes with IOP spikes were phakic, except for one with pseudophakic angle closure. Analysis of 381 participants with at least one phakic eye revealed that higher post-mydriatic IOP and IOP changes were associated with narrower angle grading, more extensive peripheral anterior synechiae, shallower central anterior chamber, and thicker lens. According to multiple linear regression analysis, post-mydriatic IOP was independently associated with baseline IOP and factors suggestive of crowded anterior chamber based on gonioscopic findings and central or peripheral anterior chamber depth evaluation in conjunction with lens thickness.

Post-mydriatic IOP should be measured in phakic eyes with a crowded anterior chamber. Post-mydriatic IOP spikes can be effectively blunted with intervention to prevent AAC.