Posture-Induced Intraocular Pressure Changes After Ex-press Implantation Versus Medical Therapy in Primary Open-Angle and Normal-Tension Glaucoma: A Retrospective Study

Background Posture-induced intraocular pressure (IOP) changes have been associated with glaucoma progression, and certain filtering surgeries reportedly suppress these changes. This study aimed to determine whether Ex-PRESS implantation also suppresses posture-induced IOP changes in glaucomatous eyes by comparing those treated with Ex-PRESS implantation and those under medical therapy. Methodology In this retrospective comparative chart review, 24 eyes after Ex-PRESS implantation without medications (EX group) and 31 eyes that underwent medical therapy (MED group) were analyzed. All eyes were diagnosed with primary open-angle glaucoma or normal-tension glaucoma with IOP measured by Goldmann applanation tonometry (IOPg) between 6 and 12 mmHg. Postural IOP change (ΔIOP) was defined as the difference between supine IOP (IOPisup) measured five minutes after assuming the supine position and sitting IOP (IOPisit), both measured using the iCare ic200. Results The IOPg results were comparable between groups (EX: 10.1 ± 1.7 mmHg; MED: 10.7 ± 1.2 mmHg; p = 0.2574). IOPisit was significantly lower in the EX group (EX: 9.1 ± 2.0 mmHg; MED: 10.4 ± 2.2 mmHg; p = 0.0117). IOPisup was also significantly lower in the EX group (EX: 10.2 ± 2.2 mmHg; MED: 13.7 ± 2.6 mmHg; p < 0.0001). Both groups had significant increases from IOPisit to IOPisup (EX: p = 0.0006; MED: p < 0.0001). ΔIOP was significantly smaller in the EX group (EX: 1.0 ± 1.3 mmHg; MED: 3.3 ± 2.2 mmHg; p < 0.0001). Conclusions Glaucomatous eyes treated with Ex-PRESS implantation had smaller posture-induced IOP changes than the medically treated eyes with similar IOP levels. These findings suggest that Ex-PRESS may offer additional benefits in stabilizing IOP variability beyond IOP reduction alone.