Purpose: To evaluate the effect of filtering surgery using the EX-PRESS device on intraocular pressure (IOP), flare count, anterior chamber (AC) depth, and the corneal endothelium in primary open-angle glaucoma (POAG), including normal-tension glaucoma (NTG).
Patients and methods: The study comprised 63 consecutive patients with POAG or NTG. They underwent complete ophthalmologic examinations, including measurement of visual acuity (VA), IOP, flare count, AC depth, and cell density of the corneal endothelium (CE). Two outcomes were used for surgical success: outcome 1 was defined as a ≥20% reduction in the IOP from the preoperative value, with an IOP ≥ 5 mmHg but ≤18 mmHg, and outcome 2 was defined as a ≥20% reduction in the IOP, with an IOP ≥ 5 mmHg but ≤15 mmHg.
Results: The IOP significantly decreased from 17.7 preoperatively to 12.4 mmHg postoperatively (P < 0.0001). The success rates for outcome 1 at 24 months were 81.3 and 46.7% for POAG and NTG, respectively (P = 0.0065); the corresponding success rates for outcome 2 were 79.4 and 46.7% (P = 0.0120). The flare count significantly increased on postoperative day 1 (P = 0.0002) but recovered to insignificant levels by day 3 (P = 0.0686). A transient decrease in AC depth was observed by 4 weeks after surgery (P = 0.0017). The CE changed from 2529 preoperatively to 2428/mm2 at 24 months (P = 0.0089).
Conclusion: The advantage of filtering surgery using the EX-PRESS device includes reduced inflammation, and the disadvantages include loss of the CE and reduced effectiveness of NTG.
Keywords: Anterior chamber depth; Corneal endothelium; EX-PRESS; Flare count; Normal-tension glaucoma.