Are we overlooking the side effects of the drugs in our zeal to conquer ARMD?
First of all let me congratulate the authors for their work on exudative ARMD. But there are still some issues which need to be brought into account:
1. Some published studies show that even 4.0 mg of intravitreal triamcinolone has significant side effects in terms of increased IOP and more so for eyes which needed the second dose of the triamcinolone, with a few of them even needing a filtration surgery. In this particular study however 25mg of Triamcinolone has been used which may cause even more increased elevation of IOP. This issue is an important one as many of our ARMD patients have co-existing chronic open angle glaucoma with a compromised blood supply of the optic nerve head. With the intravitreal steroids induced rise in IOP, we may tilt the balance on the wrong side thereby taking their peripheral vision along with the central loss due to the ARMD.1,2,5
2. The effect of intravitreal steroids in the progression of cataract is not emphasized very much in various studies. If earlier cataract surgery in treated ARMD patients is required, this has theoretical implications in terms of ultraviolet light exposure – one of the environmental factors implicated in ARMD. If there is no long term benefit for preventing the progression of ARMD with the steroids then why should we increase the chances of cataract in these patients thereby rendering their retina more vulnerable to damage caused by the UV radiation?2
3. Various in vitro studies suggest that down-regulation of inflammatory markers and changes in the endothelial cell permeability are probably the modes of action of triamcinolone in exudative ARMD, but all these actions are probably only for the duration when the steroids are in high concentration in the vicinity. To maintain high concentrations triamcinolone should be injected repeatedly and probably that is the reason the improvement fades with time in many patients. Moreover none of the studies published so far have been long enough to actually give a fair idea about the long term outcome. The longest duration for which the follow up has been done is 18 months.3,4
We need data from multicenter, placebo-controlled trials on a much larger population with long-term follow-up to establish the efficacy of the drug and assess possible side effects and complications. Until then we should probably reserve this therapy for those cases where there is recurrence after laser treatment.5
