Ophthalmic viscoelastic device injection for the treatment of flat anterior chamber after trabeculectomy: a case series study

PURPOSE Flat anterior chamber (FAC) in association with overfiltration is a complication after trabeculectomy. The aim of the current study was to investigate the efficacy of injection of an ophthalmic viscoelastic device (OVD) to treat FAC after trabeculectomy in a retrospective consecutive case series study. MATERIALS AND METHODS Twenty-five consecutive patients who underwent injection of OVD for the treatment of FAC after trabeculectomy were analyzed. The primary outcome variable was the qualified success of trabeculectomy, which was defined at three different levels by the achievement of one of three IOP-related criteria with or without glaucoma medication. Kaplan-Meier plots were generated to estimate survival functions for trabeculectomy with OVD injection. RESULTS Twenty-one patients (21/25 = 84.0%) recovered from FAC by one OVD injection. The postoperative intraocular pressure (IOP) measured at 12 months, 24 months, 36 months, 48 months, and 60 months was 14.7 ± 3.6 mmHg, 15.6 ± 7.0 mmHg, 14.2 ± 2.8 mmHg, 14.2 ± 3.8 mmHg, and 14.6 ± 2.7 mmHg, respectively. All postoperative IOP measurements were significantly lower than the preoperative IOP (P < 0.001). The probabilities of qualified success for 5 years after trabeculectomy with OVD injection were as follows: 24.4% (IOP ≦ 21 mmHg and ≧20% reduction of preoperative IOP), 16.5% (IOP ≦ 16 mmHg and ≧20% reduction) and 6.3% (IOP ≦ 12 mmHg and ≧30% reduction). One patient, who had undergone deep lamellar keratoplasty, experienced a complication associated with the injection of the viscoelastic material, Descemet's membrane detachment. CONCLUSION Injection of OVD may be effective for the treatment of FAC; however, the long-term success rate was relatively low.