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

Purpose: 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.

Methods: 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.

Results: 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.

Conclusions: 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.