Primary Outcome Measures:
- The proportion of eyes showing an improvement of visual acuity by 10 letters on a LogMAR chart compared with the pre-injection level 24 months after treatment
- The incidence of moderate or severe side effects related to the procedure of intravitreal injection or related to the drug
Secondary Outcome Measures:
- Any change in visual acuity compared with the pre-injection level
- Number of laser treatments required for the treatment of macular oedema during the course of the study.
- Change in retinal thickness demonstrated on optical coherence tomography (OCT)
A 25 fold increase in the risk of going blind on diagnosis of diabetes is one of the most daunting threats that people with diabetes face. Stimulated by several uncontrolled, anecdotal reports, we are already conducting a randomized clinical trial of intravitreal triamcinolone for the treatment of diabetic macular edema which is refractory to conventional laser treatment. The analysis of the 3 month data from this study has already unequivocally demonstrated that the treatment very significantly reduces or eliminates macular oedema in the short term and results in improved visual acuity. Thus intravitreal triamcinolone may represent the most significant development in the prevention of blindness in people with diabetes since the introduction of laser treatment. It is also a highly cost-effective intervention that can be administered by general ophthalmologists. The next question to be answered, which will be addressed directly by the present study, is whether there is a significant, synergistic beneficial effect when intravitreal steroids are combined with current therapy (laser).
This study represents the second major project to be undertaken by the Australian Retinal Collaboration (ARC). The ARC aims to set the highest attainable standards for investigator-initiated clinical research in retinal diseases in Australia. Having enrolled and treated more than the target of 120 patients, we are currently completing an RCT of laser induced chorioretinal anastomosis for central retinal vein occlusion, an innovative Australian concept for a severe and otherwise untreatable disease. The proposed study is likely to identify an improved and economical treatment for one of the commonest causes of blindness both in Australia and the rest of the world. Intravitreal triamcinolone is also an intervention which has generated intense interest internationally, and one for which members of the ARC are acknowledged pioneers.
Successful implementation of the study proposed, which is feasible, is highly likely to have an immediate and direct effect on the prevention of vision impairment and blindness in people with diabetes