In-office Techniques to Manage Tamponade-related Elevated IOP

Quick solutions to common problems can save time and money.

STEVE CHARLES, MD, FACS, FICS • STEPHEN HUDDLESTON, MD

The senior author first described in-office two-needle fluid-gas exchange to manage postvitrectomy retinal detachment and has often utilized repeated paracentesis when topical glaucoma medications were not sufficient.¹

These two techniques led to the development of two methods reported here to manage the particulate glaucomas. “Particulate glaucoma” is a term coined by the senior author to describe elevated intraocular pressure causing optic nerve damage, typically in a postoperative scenario secondary to silicone oil emulsification, perfluorocarbon liquid droplets, lens material, and erythroclasts.

Silicone oil emulsification is caused by saccade-induced shear, which is often exacerbated by inadequate fill and surfactants, such as blood, inflammatory proteins, and viscoelastic agents.² There is no solid evidence that 5,000-cSt silicone oil produces less emulsification than 1,000-cSt oil.

Silicone oil droplets are immiscible in aqueous; they are not absorbable, and they have a lower specific gravity than aqueous humor; therefore, they float. Silicone oil emulsification droplets migrate to the highest central point of the corneal endothelial surface when phakic, aphakic, or pseudophakic patients are supine.

REMOVAL OF EMULSIFICATION

Two 30-gauge needles are used: one for infusing balanced saline solution and the other for egress of the silicone oil droplets. Both needles are placed through the limbus: the infusion needle over the iris and the egress needle temporally. The infusion needle should be inserted almost parallel to the limbus, slightly into the anterior chamber in phakic eyes, with tip above the iris, bevel sideways, directed away from the cornea and iris.

A 20-cc syringe filled with BSS is connected to the 30-gauge needle using 3-inch extension tubing; an assistant must generate sufficient pressure to force BSS through the 30-gauge injection needle controlled by the surgeon. The temporal, egress needle should be positioned bevel up, as close to the corneal endothelium as possible.

An operating microscope or loupes should be used if available to enable precise positioning of the egress needle tip. The procedure may be considered complete when silicone droplets are neither present against the endothelium nor circulating in the anterior chamber.

REMOVAL OF ANTERIOR-CHAMBER PFO

The senior author has been using medium-term perfluoro-octane (PFO) for more than 20 years to repair inferior retinal detachments with or without proliferative vitreoretinopathy and giant breaks.^1,3,4 Because of relatively low surface tension, as well as inflammation, PFO often forms many small droplets in the postoperative period despite the use of a MedOne Surgical (Sarasota, FL) dual-bore cannula to inject, which always creates a single PFO bubble. These bubbles are very challenging to completely remove at the two week PFO removal procedure.

Residual droplets are often entrained in the zonules, in the capsular bag of pseudophakic eyes, and in the residual peripheral vitreous, and they migrate into the inferior anterior chamber after the PFO removal procedure.

These droplets have been implicated in secondary open-angle glaucoma and should be removed using an in-office procedure. This procedure should be performed with the patient seated at the slit lamp, using a 30-gauge needle inserted through the limbus, from one o’clock temporally to six o’clock, so the needle tip ends up in the lowest point of the anterior chamber. The needle must be inserted bevel up, and a tuberculin syringe with the plunger removed should be used as a handle.

The viscosity of PFO (0.67 cSt) is less than that of aqueous, so the IOP provides sufficient pressure gradient to remove the PFO. When the anterior chamber shallows, the needle must be removed; more caution is required in phakic eyes. The anterior chamber will spontaneously refill, and the procedure can be repeated. Both of these above procedures should be performed after a standard povidone-iodine prep with a sterile bladed speculum, and the surgeon and assistant should wear sterile gloves.

CONCLUSION

In our experience, these procedures have proved to be universally successful in safely resolving ocular hypertension, secondary to silicone oil or PFO interfering with trabecular meshwork function and thus preventing the development of particulate glaucoma.

The main benefit of incorporating both of these methods into any retina practice lies in providing an immediate solution to a problem, the typical resolution of which requires the time and expense of a trip to the operating room. RP

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