Purpose: To report a simultaneous iris angiography (IA) technique combined use of indocyanine green (ICG) and fluoresceine(FS) in pigmented and albino rabbits using a new designed positioning system and confocal scanning laser ophthalmoscope (CSLO)..

Methods: An easily adjusted control system was designed to position the CSLO scanning lens perpendicular to the surface of the iris. Then, the study was divided into 2 parts. In the 1st, to observe the effect of eyeball position system. 12 albino rabbits were randomly divided into 2 groups. Group A:  using 5 mg fluorescein sodium and 5 mg indocyanine green, iris angiograms (IA) of 6 albino rabbits were performed with application of the positioning system. Group B: using 5 mg fluorescein sodium and 5 mg indocyanine green, IA of 6 albino rabbits were performed without the positioning system. The time spending on vertical eye position and the effects of simultaneous IA were observed. In the 2nd, to choose the moderate dose of dye for best visualization in pigmented rabbits. 15 pigmented rabbits were randomly divided into 3 groups according dye doses, the dose at lower volume group was 2 mg FS and 2 mg ICG; the moderate volume group was 5 mg FS and 5 mg ICG; the higher volume group was 8 mg FS and 8 mg ICG. 15 IAs were performed by confocal scanning laser ophthalmoscope (CSLO) and. the effects of simultaneous IA were observed.

Results: In the 1st, With the help of positioning system, the iris of albino rabbits were quickly achieved the vertical site at averaged 37.50±8.17 s in Group A, otherwise, it needed 408.33±58.79s in Group B. The difference was significant statistically (t =- 15.30, P <0.05), and the time was saved averagely 370.83 s. Comparing with the previous documents of single-dye angiography photo, simultaneous digital angiography provided two kinds of full, dynamic video of iris vessels fluorescein in all albino rabbits. The emergence time of IFA and ICGA was 5-9 s, with an average for ICGA of 6.4 s, and for IFA of 6.5 s. Except for leakage, the simultaneous ICGA and IFA appearance of this vascular pattern was the same as the single IFA described previously. Normal blood vessels were clearly displayed after two minutes by ICGA with no leakage, but in IFA, clear vessels were maintained for approximately 20 s, with subsequent loss of resolution from leakage. In the 2nd, Simultaneous digital angiography provided two kinds of full, dynamic video of iris vessels fluorescein in all pigmented rabbits which is the same as in albino rabbits and no vascular pattern was hidden by the iris stromal pigment. Furthermore, dye doses influenced IA effect in pigmented rabbits. lower volume dye can demonstrate iris vessels and without obvious leakage, but they extinguished rapidly at 10~15 sec late; in higher volume group, vascular imaging lasted longer, but subsequently significant FS and ICG leakage appeared as streams on the surface of the iris until the dye disappeared from the iris vessels, the diffuse and intense aqueous fluid lasted 1 d; moderate volume dye displayed vessels clearly by ICG in 300 sec and no leakage, and FS clear vessels maintained about 15~20 sec and the structure of the iris became fuzzy due to quick leakage.

Conclusions: Simultaneous IA with a rapid localisation technique allows high-quality imaging of the albino and pigmented rabbit and the moderate dosage of 5 mg FS and 5 mg ICG is a preferred for best visualization.