A comparison of the number of Lucentis injections(eye injections) required for patients who receive a combination treatment of laser bypass (chorioretinal venous anastomosis) and Lucentis or sham laser bypass and Lucentis for the treatment of macular oedema (swelling at the back of the eye) that has occurred as a result of a central retinal vein occlusion.
A comparison of the number of Lucentis injections required within the observational period 12-24 months post enrolment in patients treated with a combination therapy of Lucentis and laser induced chorioretinal venous anastomosis (L-CRA) or Lucentis and sham L-CRA for macular oedema that is secondary to central retinal vein occlusion.
Lions Eye Institute
58 participants
Mar 2, 2012
Interventional
Conditions
Summary
Macular oedema that is secondary to central retinal vein occlusion (CRVO) has conventionally been treated with laser photocoagulation. The outcomes of this treatment show a slight improvement in visual acuity. Recently various therapeutic agents such as Triamcinolone, Pegaptanib, Bevacizumab and Ranibizumab have been injected intravitreally into the eye. Bevacizumab and Ranibizumab in particular have been shown to reduce macular oedema in the short term, however, repeated injections are required. The Central Vein Bypass Study, where a high intensity laser is used to create an anastomosis between the a retinal and a choroidal vein as a means of bypassing the obstruction to venous flow (L-CRA), is the only study to date that has addressed the causal pathology of macula oedema secondary to CRVO, rather than simply addressing the sequelae of the retinal venous obstruction. Patients who received the L-CRA had significantly improved visual acuity compared to the sham L-CRA treatment group. In this study patients will either be treated with the L-CRA or sham L-CRA. Both groups will receive monthly injections of Ranibizumab for 6 months. Patients will be assessed for a further 18 months, and may/may not receive further injections depending on whether the retreatment criteria have been met. The primary aim of the study is to show that L-CRA treated patients will require fewer Ranibizumab injections in the 12-24 month phase of the study compared to sham L-CRA treated patients. The use of Ranibizumab in the short term and the long term treatment effects of the L-CRA may prove to be an effective treatment for macular oedema that is secondary to CRVO. A recent study showed that 56% of patients had persistent macular oedema requiring an average of 5.9 injections in the 4th year. The study protocol has been amended to follow the two treatment groups bimonthly or once every four months for a further 24 months. Patients will be assessed according to the retreatment criteria for further injections. The extension study will provide long-term follow up data.
Eligibility
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Interventions
Study participants will either be randomised to receive laser induced chorioretinal venous anastomosis (L-CRA) or sham L-CRA. The Ellex diode laser will be used to create the anastomosis. Two sites will be chosen, with one above and one below the optic disc. Both will be over a tributary of a major quadrantic vein at least 2 disc diamteres away from the optic disc. It is not possible to be absolutely specific about the location as this will depend on the individual anatomical arrangement in each patient's eye. The spot size for the L-CRA treatment is 50 um and 500 um for the sham L-CRA, whilst the power will be up to 4W depending on the degree of cataract for the L-CRA, and <100mW for the sham L-CRA. The duration will be 0.1 sec for both treatment groups. There is only one laser session, that consists of two attempts to establish a functional L-CRA. Both treatment groups will receive monthly intravitreal injections of Lucentis (Ranibizumab) for 6 months after the laser treatment.The dose for each intravitreal injection is 2.3mg/0.23mL(10mg/mL) solution, and the volume injected is 0.05ml. The intravitreal injection procedure including the application of local anaesthetic and cleaning of the conjunctiva will take about 20 minutes. After the first six injections, patients will be evaluated monthly, and may receive further Lucentis injections based on protocol retreatment criteria. The retreatment criteria are: 1. There is a >50um increase in central thickness on spectral domain OCT compared to the lowest previous measurement, 2. There are new or persistent cyctic retinal changes or subretinal fluid on spectral domain OCT, and 3. There is a loss of 5 or more ETDRS chart letters from the previous best measurement in conjunction with any increase in central foveal thickness on spectral domain OCT. For the first 2 years of the study, patient visits will be monthly. In the extension study (years 3-4) patients in both treatment groups will be evaluted at 2 or 4 month intervals for Lucentis retreatment using the retreatment criteria outlined above.
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ACTRN12612000004864