Topical interferon - A novel treatment for pseudophakic macular edema

Purpose: The aim of this study was to evaluate the efficacy of topical interferon (IFN) therapy in pseudophakic cystoid macular edema (P-CME). Methods: This is a prospective, interventional case series of patients with P-CME. Patients presenting with P-CME were given the option of topical IFN therapy against conventional treatment with oral, topical, intravitreal, and periocular steroid therapy and antivascular growth factors. Patients who consented for the same were advised to use the IFN drops four times/day. Commercially available injection IFN alfa-2b was reconstituted to prepare the eye drops (1 MIU/ml). Optical coherence tomography (OCT) was done at the baseline and on each review visit until complete resolution of P-CME. Results: Eight eyes of eight patients diagnosed with P-CME were studied. Mean central macular thickness (CMT) on OCT at the presentation (n = 8) and at 4 weeks post topical IFN therapy (n = 6) was 560.1 mu m (range: 349-702 mu m) and 344.33 mu m (range: 250-390 mu m), respectively. All eyes except one had posterior capsular rent (PCR). Five patients had regular follow-up until resolution. The mean duration of complete first resolution of P-CME was 5 weeks (range: 4-7.1 weeks) in those patients. Relapse was seen in three patients who responded after resuming or continuing the therapy. Case 1 had 9 months follow-up after completion of IFN therapy, and no recurrence was noted. No ocular or systemic side effects related to the topical IFN therapy were noted clinically, except papillary conjunctivitis in one patient. Conclusion: Topical IFN therapy can be a noninvasive, economical, and effective choice of treatment for P-CME, especially in the case of PCR, and where steroids are contraindicated.