Evaluation of the toxicity of subretinal triamcinolone acetonide in the rabbit.
OBJECTIVE
Subretinal triamcinolone acetonide (TCA) might be a useful adjuvant in the treatment of subretinal neovascularization. The purpose of this study was to test the toxicity of subretinal TCA in the rabbit eye.


METHODS
Sixteen New Zealand rabbits were vitrectomized and injected with either decanted TCA solution or vehicle. The concentration of injected TCA was 2 mg, and the delivered volume was 10 microL. Rabbits were examined on days 1, 3, and 7 and then once a week up to 3 months after surgery. Optical coherence tomography was performed at months 1, 2, and 3. After the last examination, which included electroretinography, the rabbits were killed, and the eyes were enucleated for histopathologic analysis.


RESULTS
Subretinal TCA appeared as a white circumscribed deposit. As the drug disappeared, areas of hyperpigmentation were seen adjacent to the drug deposit. Electroretinography tracings were normal, indicating no widespread toxic effect. Histologic analysis revealed areas of absence and/or hyperpigmentation of the retinal pigment epithelium and damage to photoreceptors and the outer nuclear layer of the retina.


CONCLUSIONS
Subretinal injection of TCA crystals can be toxic to the outer retina and retinal pigment epithelium. Whether the potential beneficial effect of such a high-dose steroid in limiting subretinal inflammation, angiogenesis, and proliferation outweighs toxicity can only be determined from a clinical trial.
Kozak
Igor
I
Jacobs Retina Center, University of California at San Diego, Shiley Eye Center, La Jolla, California 92036-0946, USA.
Cheng
Lingyun
L
Mendez
Tim
T
Davidson
Marie C
MC
Freeman
William R
WR
D000818:Animals; D004596:Electroretinography; D005938:Glucocorticoids / Q000633:toxicity*; D007267:Injections; D008297:Male; D010857:Pigment Epithelium of Eye / Q000187:drug effects* / Q000473:pathology; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000473:pathology; D041623:Tomography, Optical Coherence; D014222:Triamcinolone Acetonide / Q000633:toxicity*; D014821:Vitrectomy
D005938:Glucocorticoids; D014222:Triamcinolone Acetonide