OCT can determine ranibizumab re-treatment rate

Optical coherence tomography (OCT) is a useful tool for determining when re-treatments with ranibizumab are required in patients with neovascular age-related macular degeneration (AMD), according to the results of a study published in the April issue of the American Journal of Ophthalmology.

Anne E. Fung from the Bascom Palmer Eye Institute, Florida, USA and colleagues from Pacific Eye Associates, California and the University Eye Hospital Vienna, Austria conducted an open-label, prospective, single-centre, non-randomized, investigator-sponsored clinical study to evaluate an OCT-guided, variable dosing regimen with intravitreal ranibizumab for the treatment of patients with neovascular AMD.

During the two-year study, neovascular AMD patients (n=40) with subfoveal choroidal neovascularization (CNV) and a central retinal thickness of at least 300 µm were enrolled to receive three consecutive monthly intravitreal injections of ranibizumab (0.5 mg). Re-treatments were performed if any of the following were observed between visits: a loss of five letters in conjunction with fluid in the macular as detected by OCT, an increase in OCT central retinal thickness of at least 100 µm, new-onset classic CNV, new macular haemorrhage or persistent macular fluid at least one month after the previous injection.

At 12 months follow-up, mean visual acuity (VA) had improved by 9.3 letters (p<0.001) and mean central thickness had decreased by 178 µm (p<0.001). In 35% of patients, VA had improved by 15 or more letters. The VA and OCT outcomes were achieved with an average of 5.6 injections over 12 months. After a fluid-free macular was achieved, the mean injection-free interval before re-injection was required, was 4.5 months.

It would seem that an OCT-guided, variable-dosing regimen can result in good VA outcomes with fewer injections. The authors also concluded that OCT is a useful tool for determining when re-treatments are required.