Iontophoresis of reactive black 5 for pulsed dye laser sclerostomy.
Ab interno pulsed dye laser sclerostomy uses a gonioscopic approach to form a limbal fistula for the treatment of glaucoma. This procedure requires a full thickness penetration of stain in sclera for adequate absorption of the visible light energy. Iontophoresis is a technique using an electrical current to noninvasively deliver Reactive Black 5 (RB5) stain into sclera. This project determined the stability of RB5 stain as well as the optimal parameters for iontophoresis (probe tip surface area, current, and duration) in a rabbit model. RB5 stain was stable over time (72 hr) as well as after exposure to extreme heat (120 degrees C), scleral constituents (namely collagen), high concentrations of oxidants (1.5% H2O2), and laser light energy. Ideal parameters for iontophoresis included a probe tip surface area between 0.1 and 0.7 mm2, a current of 0.5 mA, and a duration of 5 min. The maximum concentration of RB5 stain achieved in sclera was 0.15%. The threshold of ablation for RB5 using an energy of 250 mJ was 0.001%. Iontophoresis can effectively deliver RB5 stain into sclera and may be a viable adjunct to ab interno pulsed dye laser sclerostomy procedures in the eye.
Sarraf
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Jules Stein Eye Institute, UCLA School of Medicine.
Lee
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DA
D000818:Animals; D007478:Iontophoresis / Q000379:methods*; D053685:Laser Therapy; D009282:Naphthalenesulfonates / Q000493:pharmacokinetics*; D011817:Rabbits; D012590:Sclera / Q000378:metabolism; D012599:Sclerostomy
D009282:Naphthalenesulfonates; C063421:Remazol black B