From the Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, Florida.
Dr. Flynn is a consultant for Alcon, Allergan, Pfizer, and Santen. The remaining authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to Harry W. Flynn, Jr., MD, Bascom Palmer Eye Institute, 900 NW 17th Street, Miami, FL 33136. E-mail: firstname.lastname@example.org
The Ex-PRESS mini glaucoma shunt (Optonol Ltd., Neve Ilan, Israel) is a small, nonvalved device that was developed as an alternative procedure to trabeculectomy and other types of glaucoma filtering surgery to lower intraocular pressure (IOP) in eyes with glaucoma.1 Complications following Ex-PRESS mini glaucoma shunt implantation include postoperative endophthalmitis, hypotony, cataract, and choroidal detachment.2,3 We describe a patient with delayed-onset endophthalmitis caused by Bacillus sp. following implantation of the Ex-PRESS mini glaucoma shunt.
A 92-year-old man presented to the emergency department with a 3-day history of pain, redness, and decreased vision in the left eye. He had a history of primary open-angle glaucoma in both eyes. The patient had sustained an injury to the right eye approximately 10 years earlier, leading to phthisis and blindness. He underwent Ex-PRESS mini glaucoma shunt implantation in the left eye 3 years and 4 months prior to presentation, which was followed by a Baerveldt implant 3 years and 2 months prior to presentation for poorly controlled primary open-angle glaucoma.
His best-corrected visual acuity at presentation was no light perception in the right eye and light perception in the left eye. Intraocular pressure was 27 mm Hg in the left eye. He was pseudophakic in the left eye. There was 3+ conjunctival injection with an edematous and hazy cornea. The anterior chamber was formed and had a 2-mm hypopyon, moderate fibrin, and a patent Ex-PRESS shunt (Fig. 1). Baerveldt implant was adequately covered with conjunctiva with a moderate bleb. Seidel test was positive over the Ex-PRESS mini glaucoma shunt. In the left eye, fibrin on the intraocular lens and vitreous cells obscured visualization of the retina.
Figure 1. Left eye on presentation showing conjunctival congestion. Anterior segment with edematous cornea, fibrin, and hypopyon. Ex-PRESS mini glaucoma shunt (Optonol Ltd., Neve Ilan, Israel) visible at 12-o’clock position.
After a diagnosis of endophthalmitis associated with the shunt was made in the left eye, the patient underwent vitreous tap followed by intravitreal injections of vancomycin (1 mg/0.1 mL), ceftazadime (2.25 mg/0.1 mL), and dexamethasone (0.4 mg/0.1 mL), along with subconjunctival injection of vancomycin (50 mg/0.5 mL) and tobramycin (20 mg/0.5 mL).
The vitreous specimen showed Bacillus sp. on Gram stain, non-anthracis. Culture media also grew Bacillus sp., which was sensitive to vancomycin, ceftazidime, gentamicin, moxifloxacin, erythromycin, and ciprofloxacin. Fortified vancomycin, prednisolone acetate, and scopolamine were administered topically to the left eye.
After treatment, his pain decreased and the fibrin on his intraocular lens started contracting with resolution of hypopyon. At the 1-month follow-up visit, visual acuity was 3/200 in the left eye with resolution of fibrin and hypopyon in the anterior chamber (Fig. 2). The Baerveldt implant remained covered with conjunctiva and had no erythema or discharge. Seidel testing was negative. The vitreous cells had also reduced. Poor vision was due to near total cupping of the optic nerve head. The patient refused surgery to revise or remove the Ex-PRESS mini glaucoma shunt.
Bacillus is a genus of spore-forming Gram-positive rods that may cause a rapidly progressive endophthalmitis. Bacillus grows rapidly in the vitreous and induces damage through a toxin-mediated mechanism and intraocular inflammation.4 It is an uncommon cause of postoperative endophthalmitis except in the setting of open globe injuries and intraocular foreign bodies.
There are two previous reports of delayed-onset endophthalmitis associated with bleb caused by Bacillus and also two previous reports of endophthalmitis following Ex-PRESS mini glaucoma shunt implantation.5,6 These two later reports were associated with conjunctival erosion or bleb leak as noted in the current patient.3,7 A leak was noted at the site of the shunt with a positive Seidel test and was probably the source of bacterial entry into the anterior chamber. Although Bacillus sp. are sensitive to most antibiotics, vancomycin and quinolones have the greatest potency, as reported by our earlier case series.6
It is still controversial if one has to explant the Ex-PRESS mini glaucoma shunt in the event of endophthalmitis. The patient refused the medical recommendation to remove or revise the shunt and was successfully treated medically without removing the shunt, setting this case apart from other reported cases. This case demonstrates that despite the Ex-PRESS mini glaucoma shunt’s ease of use, endophthalmitis is still a potential complication when leakage or exposure occurs.
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- Stewart RM, Diamond JG, Ashmore ED, Ayyala RS. Complications following Ex-PRESS glaucoma shunt implantation. Am J Ophthalmol. 2005;140:340–341. doi:10.1016/j.ajo.2005.02.033 [CrossRef]
- Callegan MC, Cochran DC, Kane ST, et al. Virulence factor profiles and antimicrobial susceptibilities of ocular bacillus isolates. Curr Eye Res. 2006;31:693–702. doi:10.1080/02713680600850963 [CrossRef]
- Hemady R, Zaltas M, Paton B, Foster CS, Baker AS. Bacillus-induced endophthalmitis: new series of 10 cases and review of the literature. Br J Ophthalmol. 1990;74:26–29. doi:10.1136/bjo.74.1.26 [CrossRef]
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- Maris PJ Jr, Ishida K, Netland PA. Comparison of trabeculectomy with Ex-PRESS miniature glaucoma device implanted under scleral flap. J Glaucoma. 2007;16:14–19. doi:10.1097/01.ijg.0000243479.90403.cd [CrossRef]
Figure 2. Left eye at 3-week follow-up showing further improvement of conjunctival congestion. Anterior segment with further resolution of corneal edema and contraction of fibrin. Ex-PRESS mini glaucoma shunt (Optonol Ltd., Neve Ilan, Israel) visible at 12-o’clock position.