Abstract
Purpose: :
To investigate the retinal toxicity by Electroretinography (ERG) and fundoscopy after intravitreal injection of the biological stains in two concentrations: Trisodium (0.50 g/L and 1.00 g/L), Orangell (0.25 g/L and 1.00 g/L) and Methil Violet (1.00 g/L and 0.50 g/L).
Methods: :
Nineteen New Zealand Albinos rabbits were assigned in six groups (n = 3 in each group except for the group 5 n=4). The animals in group 1 received Trisodium (8-Hydroxypyrene-1,3,6-Trisulfonic Acid Trisodium) in the dose of 0.50 g/L and group 2 received 1.00 g/L. Group 3 received Orangell in the dose of 0.25 g/L and group 4 received 1.00 g/L. Group 5 received Methil Violet in the dose of 1.00 g/L and group 6 received 0.50 g/L. A volume of 0,1 mL of dye was injected in the right eyes, whereas the left eyes received the same volume of balanced salt solution (BSS) as control. ERG recordings were performed at baseline and 7 days after intravitreal injection. Ephios handheld system (Ephiós AB, Rejmyre, Sweden), ERG-jet and skin electrodes were used. Scotopic and fotopic curves were measured (Fig 1). Amplitude of waves were obtained by transferred data to software Mjolner v1.3:0.5. The responses at 1 week after injection were compared with baseline levels. A decrease in the post-injection amplitude of more than 66% was considered remarkable.
Results: :
At clinical examination by indirect ophthalmoscopy 7 days after dye injection, all eyes were negative for cataract, hemorrhage, retinal detachment, and intraocular opacities. Amplitude analysis of minimal scotopic b-wave (ROD) , maximum (MAX) scotopic a- and b-wave, photopic single flash cone b-wave (SFC) and photopic 30 Hz flicker b-wave (FLI) showed no significant reduction in either dye injected or control eyes. Descriptive comparison between dyes showed that main amplitude decreasing, was in the Methil Violet groups (5 and 6) in both scotopic an photopic recordings (Table 1). One rabbit in group 5 (Methil Violet 1.00g/L) was found dead 7 days after dye injection. No other adverse effects were observed in our study.
Conclusions: :
Trisodium, Orangell and Methil Violet can be applied in future studies in order to prove the capacity to stain preretinal membranes and vitreous without toxicity. The three dyes did not induce significant ERG amplitude reduction in this preliminary experimental research. Further histopathological analysis may corroborate ERG amplitude analysis. Trisodium, Orangell and Methil Violet may be promising vital dyes for ocular surgery.
Keywords: vitreoretinal surgery • retina