Pupillary Block Glaucoma After Pars Plana Vitrectomy with Air-Fluid Exchange in Pseudophakic Air-Filled Eye

Introduction

Pupillary block may occur after pars plana vitrectomy (PPV) with silicone oil injection in aphakic and pseudophakic patients^1–3 and inferior peripheral iridotomies are routinely done as a prophylactic measure. Gas-mediated pupillary block and iridocorneal apposition are known complications in aphakic eyes after PPV.^4–6 Angle closure glaucoma has also been reported after scleral buckling procedures.⁷

Pupillary block glaucoma is an ophthalmic emergency because of secondary effects such as permanent iridocorneal adhesions, posterior synechiae, iris bombé, corneal decompensation, and secondary angle closure glaucoma. We report a case of acute pupillary block glaucoma with posterior synechiae, which occurred after uncomplicated phacoemulsification and PPV and air-fluid exchange in a pseudophakic eye, and discuss possible mechanisms and management options.

Case Report

A 76-year-old woman was referred with 20/70 vision in her right eye due to an epiretinal membrane and mild nuclear sclerosis. There was no history of trauma, pseudoexfoliation, phacodonesis, or zonule weakness. Dilated fundus examination showed that she also had a posterior vitreous detachment with a horseshoe tear at 2-o’clock position. The patient underwent uneventful phacoemulsification cataract extraction with placement of posterior chamber intraocular lens (MA60AC, Alcon Laboratories, Inc., Ft. Worth, TX) and 23-gauge PPV, membrane peel, and endolaser.

On postoperative day 1, there was a poor view to the fundus due to vitreous hemorrhage. B-scan ultrasound confirmed the retina was attached. After observing for 3 weeks without change, the patient underwent 25-gauge PPV, endolaser, and air-fluid exchange. Intraoperatively, it was noted that the source of vitreous hemorrhage was a torn vessel bridging the original horseshoe tear.

One day later, an air bubble was noted to fill 80% of a deep anterior chamber with a 60% air fill in the vitreous. Intraocular pressure was 11 mm Hg. She was started on prednisolone acetate 1% QID, levofloxacin 0.5% QID, and atropine 1% BID. Five days later, the patient came in with continous pain, headache, and redness in acute pupillary block glaucoma. Two days prior to this presentation, the patient had complained of intermittent, less severe eye pain, which may have been intermittent angle closure.

Examination revealed corneal edema, mid-dilated pupil, central air bubble completely covering the pupil, 360° peripheral iridocorneal contact, posterior synechiae formation between the iris and the posterior chamber intraocular lens, iris bombé and intraocular pressure of 32 mm Hg (Fig. 1). Topical and systemic glaucoma medications were started without improvement.

Figure 1. (A–B) Color Slit Lamp Photograph Right Eye Showing Narrow Angle with Air Bubble, Complete Pupillary Block, and Iris Bombé.

Laser iridotomy could not be performed due to complete 360° iridocorneal contact. She was taken to the operating room for a surgical peripheral iridectomy. Intraoperatively, that patient was noted to have nearly 360° of posterior synechiae. The anterior chamber was entered through the original clear corneal cataract incision and the anterior chamber filled with viscoelastic. Synechiolysis was performed using a blunt 27-gauge cannula tip. A surgical peripheral iridectomy was made at the 11-o’clock position. The anterior chamber was refilled with balanced salt solution.

Two hours postoperatively, examination showed intraocular pressure of 14 mm Hg, a deep anterior chamber, open angle, and pigment from broken synechiae on the anterior face of a well-centered posterior chamber intraocular lens. Three weeks later, the vision was 20/20, anterior chamber was deep without iridocorneal touch, and intraocular pressure was 14 mm Hg off all intraocular pressure lowering medications (Fig. 2).

Figure 2. Postoperative Week Three. (A) Color Slit Lamp Photograph Right Eye Showing Absence of Air in AC, Remnants of Broken Posterior Synechiae, and a Clear Cornea. (B) Gonioscopy Photograph Right Eye Showing Deep Anterior Chamber Without Peripheral Anterior Synechiae.

Discussion

This case highlights potential mechanisms and management options of pseudophakic pupillary block glaucoma, an uncommon but serious complication after retinal surgery. It requires a mechanism of lens to iris touch either from anterior pushing, posterior forces or both.⁸ We successfully managed our patient by posterior synechiolysis, evacuating air from the anterior chamber, and surgical peripheral iridectomy.

In our patient, 2 factors promoted the formation of 360° posterior synechiae, iris bombé, and acute pupillary block glaucoma. First, we hypothesize that the patient had zonulysis, which both enabled air to move freely into the anterior chamber, and allowed for anterior displacement of the intraocular lens against the iris. Our patient did not have any risk factors for zonulysis such as trauma or pseudoexfoliation. This “anterior chamber air-iris-intraocular lens-vitreous air” sandwich created an anatomical predisposition for the formation of posterior synechiae between the iris and posterior chamber intraocular lens. Second, because the patient underwent concomitant cataract extraction, there was greater postoperative inflammation, which accelerated synechiae formation in the setting of this anatomical predisposition.

In summary, we conclude that zonular weakness may anatomically predispose to pseudophakic pupillary block glaucoma after retinal surgery with an air-filled eye. One sign of zonular weakness is when air fills the anterior chamber intra or postoperatively. Also, increased inflammation from concomitant cataract extraction in the setting of vitreoretinal surgery may promote the formation of posterior synechiae, which can lead to iris bombé and acute pupillary block glaucoma. We recommend management with evacuation of the anterior chamber air bubble, reconstituting the anterior chamber with balanced salt solution, and surgical peripheral iridectomy. Retinal surgeons should be aware of this rare but serious complication after PPV in phakic and pseudophakic eyes to recognize it early and treat it as soon as possible.