Novel Modified Ahmed FP-7 Valve with Tube extender for Retrobulbar/Intraconal Surgery in Pseudophakic Advanced Glaucoma; A 1 Year Retrospective Study in 38 Patients
Daniel Laroche MD* and Brian Grodecki MS
ABSTRACT
Purpose: Conventional Ahmed FP-7 valve placement can be limited by hypertensive phase and subconjunctival scarring. We evaluated a retrobulbar/intraconal Ahmed FP-7 technique using a posterior tube extender to divert aqueous humor away from the subconjunctival space and assess 12-month pressure, medication, visual field, and safety outcomes.
Methods: We retrospectively reviewed 38 eyes of 38 pseudophakic patients with refractory glaucoma who underwent Ahmed FP-7 implantation with superotemporal retrobulbar/intraconal plate placement and posterior tube extender at a single center. Outcomes included IOP, IOP-lowering medications, visual field mean deviation (VF MD), best-corrected visual acuity, surgical success, hypertensive phase, and adverse events. Baseline and 12-month values were compared using paired t-tests.
Results: Mean IOP decreased from 24.05 ± 10.58 to 13.39 ± 5.19 mmHg at 12 months (mean change −10.66 mmHg, 95% CI −14.40 to −6.91, p = 1.30 × 10⁻⁶). Mean medication burden decreased from 4.55 ± 1.39 to 1.87 ± 1.83 agents (mean change −2.68, 95% CI −3.45 to −1.92, p = 2.23 × 10⁻⁸). VF MD remained stable, changing from −21.99 ± 9.54 to −21.79 ± 9.18 dB (p = 0.794). Hypertensive phase occurred in 2 eyes (5.3%). Qualified success was achieved in 25 eyes (65.8%) and complete success in 8 eyes (21.1%). No diplopia, motility disturbance, tube or plate exposure, or device removal/revision occurred.
Conclusion: Retrobulbar/intraconal Ahmed FP-7 placement with a posterior tube extender achieved significant IOP and medication reduction with stable visual fields and a low hypertensive-phase rate at 12 months. This technique warrants further evaluation in larger, longer-term studies.
