How Many Fenestrations Should I Make When Placing a Baerveldt Glaucoma Implant? A Laboratory Study

Area of Science:

• Ophthalmology
• Biomedical Engineering

Background:

• Glaucoma drainage implants are crucial for managing intraocular pressure.
• Non-valved implants, like the Baerveldt, rely on fenestrations for fluid egress.

Purpose of the Study:

• To investigate the impact of one versus two fenestrations on fluid egress and opening pressure.
• To compare the efficacy of single vs. double fenestrations in non-valved glaucoma implants.

Main Methods:

• An in vitro closed system simulating Baerveldt implant tubing was utilized.
• Fenestrations were created, and fluid egress/opening pressures were measured under varying pressures.
• Micropipette and controlled pressure increases were employed for measurements.

Main Results:

• No significant difference in fluid egress between one and two fenestrations was observed below 40 mmHg.
• A statistically significant increase in fluid egress was noted with two fenestrations at 50 mmHg (P < 0.05).
• The first fenestration opened at an average of 10.5 mmHg, and the second at 28.83 mmHg.

Conclusions:

• A critical pressure threshold around 40 mmHg exists where a second fenestration significantly enhances fluid drainage.
• For preoperative intraocular pressures below 40 mmHg, one or two fenestrations may have similar effects on fluid egress and intraocular pressure control.