Effect of intravitreal injection of indocyanine green, triamcinolone acetonide and trypan blue on the electroretinographic response in the rat

Purpose: The purpose of this study was to evaluate the effects of intravitreal injection of ICG (indocyanine green), TB (trypan blue) and TA (triamcinolone acetonide) on the visual function assessed by electroretinogram (ERG) in the rat. Methods: Three groups of 12-week-old Sprague Dawley rats (n=6) received intravitreal injection in one eye of 0.1mL of either ICG 0.5mg/mL, TB 3mg/mL or TA 40mg/mL followed by a rinse with 1mL of saline solution. The controlateral eye was used as a control and was injected similarly with saline only. The scotopic ERG was recorded at different intensities (10mcds/m², 2500mcds/m² and 25000mcds/m²) before injection and 28 days after treatment. Results: No effect of the treatment was observed on the ERG amplitudes and wave latencies in control eyes and in eyes treated with TB and TA. The ERG b-wave amplitudes and latencies were significantly reduced in eyes treated with ICG at 10mcds/m² and 2500mcds/m² but not at 25000mcds/m² (amplitude means: t0=174.8μV versus t28=55.0μV at 10mcds/m² p