The use of intravitreal triamcinolone acetonide has proliferated. Indications have included macular odema secondary to diabetes mellitus, retinal vein occlusion, uveitis and pseudophakia. Other indications are treatment of choroidal neovascularisation, proliferative diabetic retinopathy, idiopathic juxtafoveal telangiectasia and intraoperative visualisation of the posterior hyaloids.
It is clear on the basis of optical coherence tomography that macular odema can resolve, often dramatically, after intravitreal triamcinolone acetonide injection.
Hypotheses regarding the mechanism of action include an anti-inflammatory effect, inhibition of vascular endothelial growth factor, improvement in diffusion and re-establishment of the blood-retinal barrier through a reduction in permeability.
The most important question that remains about the use of intravitreal triamcinolone is whether the treatment is safe. The elevation of intraocular pressure can occur in up to 50 per cent of eyes within one to two months of treatment, often necessitating medical therapy. The most feared complication is endophthalmitis.
To evaluate the safety and efficacy of intravitreal triamcinolone acetonide for macular odema in a group of patients with a variety of clinical presentations. A retrospective audit was carried out between January 2005 to July 2006 in University College Hospital, Galway.
The intravitreal triamcinolone study was done on 34 patients with a mean age of 71 and a male to female ratio of 14:20. Mean follow-up was seven months. The total number of eyes were 40 with six patients having triamcinolone in both eyes on different occasions. Intravitreal triamcinolone was given in sterile, theatre settings.
Povidone-iodine solution was used to wash the conjunctival sac and eyelids pre-operatively. Pre and post-injection paracentesis was done to decrease intraocular pressure. Post-operatively, all the patients were given g.chloramphenicol three times a day for one week and g. iopidine (one per cent) three times a day for three weeks. All the patients were seen three weeks post-operatively.
Diabetic macular odema refractory to laser treatment was indicated in 25 (62.5 per cent) eyes; macular odema, due to branch retinal vein occlusion in nine eyes (22.5 per cent); central retinal vein occlusion leading to macular odema in four eyes (10 per cent); pseudophakic macular odema in one eye (2.5 per cent) and intermediate uveitis leading to macular odema in one eye. Triamcinolone (4mg/0.1ml) was given in eight eyes (20 per cent) and 20mg/0.1ml was given in 32 eyes (80 per cent).
Eight eyes (20 per cent) had visual improvement from 6/24 pre-injection to 6/9 post-injection; two eyes (five per cent) from 6/24 to 6/6; two-line visual improvement was seen in eight eyes (20 per cent); one-line visual improvement in 13 eyes (32.5 per cent); and no visual improvement was seen in nine eyes (22.5 per cent).
Clinically, macular odema was improved in all except in two eyes. Regarding complications, one patient (2.5 per cent) had endophthalmitis and another patient had lens penetration, and eight patients (20 per cent) had high intraocular pressure (IOP).
Among those with high intraocular pressure, one patient had 4mg/0.1ml and others had 20mg/0.1ml triamcinolone injection. Five of the high IOP patients were controlled with drops, one was controlled with ALT and two needed trabeculectomy. The lens penetration patient developed a mature white cataract within two weeks.
The nucleus was dropped during cataract surgery, which subsequently needed vitrectomy to remove the nucleus from the vitreous with final visual acuity of 6/24. Three patients needed repeat injection due to recurrence of macular odema. One patient developed endophthalmitis on 2nd injection.
Intravitreal triamcinolone is a useful procedure to control macular odema in a variety of presentations but with a significant (25 per cent) risk of serious complications.