Intravitreal gas injection for the treatment of diabetic macular edema

Dominic McHugh, Bhaskar Gupta, Manzar Saeed
King's College Hospital, Denmark Hill, London, England, UK

Purpose: This study investigates the efficacy of an intravitreal gas injection in inducing a posterior vitreous detachment (PVD) in patients with clinically significant diabetic macular edema refractory to laser therapy.
Methods: A local ethics committee-approved technique of an intravitreal injection of pure perfluoropropane gas (C₃F₈) was performed for all participants. After a period of prone positioning, the patients underwent regular and detailed clinical review.
Main outcome measures: The induction of a PVD, change in macular thickness, change in visual acuity.
Results: A PVD was induced in all five eyes with subsequent signs of reduction in macular thickness and resolution of exudates. Mean visual improvement was 11 ETDRS (Early Treatment Diabetic Retinopathy Study) letters (range 4–21). Apart from a transient vitreous hemorrhage in one eye, there were no significant treatment-related complications.
Conclusion: The induction of a PVD by pneumatic retinopexy appears to have a significant influence on diabetic macular edema in eyes which have not successfully responded to macular laser therapy. A randomized clinical trial is justified on the basis of the initial promising data.

Keywords: optical coherence tomography, OCT, posterior vitreous detachment, perfluoropropane