Intravitreal cidofovir injection for the management of chronic glaucoma in dogs

Objective: The objective of this retrospective study was to determine whether an intravitreal injection of 562.5 ug of cidofovir was effective in lowering the intraocular pressure (IOP) in chronically glaucomatous avisual canine eyes.

Patients: This study reviews the medical records of 167 canine patients diagnosed with chronic glaucoma between 2006 and 2011. The criteria for study inclusion were patients with irreversibly avisual eyes that were refractory to medical management, without evidence of endophthalmitis or intraocular neoplasia as determined by historical, clinical, and/or ultrasonographic examination, who were treated with an intravitreal injection of cidofovir.

Procedure: Using only topical anesthesia for most patients, aqueouscentesis was followed by an intravitreal injection of 562.5 ug of cidofovir and 1 mg of subconjunctival triamcinolone. An initial recheck was performed 14 days following the injection.

Results: The mean IOP immediately prior to injection was 46 ± 13 mm Hg with a median of 47 mm Hg. At the initial recheck, the mean IOP was 10 ± 11 mm Hg with a median of 6 mm Hg. A common postinjection finding was mild intraocular inflammation, which was controlled in all cases with topical neopolydex solution. Post injection complications included corneal ulceration (2.4%) and endophthalmitis (2.4%). Phthisis bulbi was a common sequalae (70%). One injection of cidofovir was successful in lowering the IOP in 85% of cases (P < 0.0001); multiple injections raised the success rate to 97%.

Conclusions: An intravitreal injection of cidofovir was found to be an effective method of lowering intraocular pressure to <20 mm Hg. While the common side effect of phthisis bulbi resulted in a less than optimal cosmetic result, patients subjectively benefited from enhanced comfort warranting consideration of this approach in the management of chronically glaucomatous avisual canine eyes.