Effects of Postural Variation on Intra-ocular Pressure: Comparison between Pseudo-exfoliation Glaucoma and Primary Open Angle Glaucoma

Purpose: to compare the posture-related intraocular pressure (IOP) changes in pseudo-exfoliation glaucoma (PXFG) and in primary open-angle glaucoma (POAG) patients using the EyeOP, a novel Goldmann Applanation Tonometer (GAT) and to investigate the effect of ab externo trabeculectomy on these changes. Methods: Prospective, non-randomized, controlled, observational study. IOP was measured in sitting and in left lateral decubitus positions (LLDP), using GAT, GAT-EyeOP and Tonopen XL. Main Outcome Measure: Posture-related IOP differences between groups. Results: Thirty-two eyes of 32 PXFG patients (21 non-operated, 11 post-trabeculectomy) and 47 eyes of 47 POAG patients (18 non-operated, 29 post-trabeculectomy) were included. Among non-operated patients, the average increase in GAT IOP between positions ( increment IOP) was 2 +/- 1.86 mmHg for the PXFG group and 1.9 +/- 2.84 mmHg for the POAG group (P = .87). The increment IOP among operated patients (1.72 +/- 1.9) was slightly less than in non-operated (1.6 +/- 2.69; P = .905). Generally, in the LLDP, the mean difference between GAT and Tonopen XL IOP measurements was 1.9 +/- 3.83 mmHg (r = 0.643; P < .001). A similar correlation was demonstrated between tonometers when measured in the sitting position. Conclusions: Both PXFG and POAG patients have increased IOP in LLDP as compared to an upright position, with no statistically significant difference between groups. Trabeculectomy had no significant effect on the increment IOP.