Asymmetric Intraocular Pressure Changes in Dominant and Contralateral Eyes: The Dark Room Prone Provocative Test

To evaluate changes in intraocular pressure (IOP) in dominant and contralateral eyes following the dark room prone provocative test (DRPPT) in the study subjects with shallow anterior chamber.

This was a prospective, single-center, non-randomized controlled trial of 43 subjects (86 eyes) with shallow anterior chamber. The dominant eye was identified using the card-hole method. The study subjects underwent the DRPPT for one hour. Pre- and post-DRPPT IOP was measured using an I-Care tonometer, and pupillary parameters, including amplitude of constriction, peak constriction velocity, and peak re-dilation velocity, were also measured using the RAPDx® dynamic pupillometer.

Significant increases in IOP were observed in both the dominant and contralateral eyes after DRPPT, compared to their respective pre-DRPPT IOP levels. (p < .01). Moreover, IOP variation before and after DRPPT was significantly greater in the dominant eye than in the contralateral eye (median 3.60 mmHg vs. 2.70 mmHg, p < .05). The dominant eyes exhibited a smaller amplitude of constriction (1.07 ± 0.35 mm vs 1.14 ± 0.34 mm, P < .05) and slower constriction velocity (3.71 ± 1.12 mm/s vs 3.78 ± 1.11 mm/s, P < .05) as compared to the contralateral eyes.

This study demonstrated that the dominant eye exhibited greater IOP changes after DRPPT than the contralateral eye. Additionally, it showed smaller pupil constriction and slower contraction, indicating a higher likelihood of pupil blockage in the dominant eye with shallow anterior chambers. This asymmetry partially explains the monocular onset of acute angle-closure attacks.