TY - JOUR AU - Lee, David A AU - Kotas-Neumann, Ronit AU - Dukes, Andres J PY - 1997/03/01 Y2 - 2024/03/29 TI - Gonioscopic laser sclerostomy: comparing the ablation capacities of methylene blue and reactive black stains in vitro and in vivo JF - Hong Kong Journal of Ophthalmology JA - Hong Kong J Ophthalmol VL - 1 IS - 1 SE - Original Articles DO - UR - https://hkjo.hk/index.php/hkjo/article/view/168 SP - 25-32 AB - <p><strong>Aim: </strong>Gonioscopic laser sclerostomy requires staining of the sclera by an iontophoresis technique to permit the absorption of the laser energy. The ablation ability of a pulsed dye laser using methylene blue as scleral stain was compared to that using reactive black in order to evaluate which stain is more effective for achieving a full-thickness sclerostomy, both <em>in vitro </em>and <em>in</em><em> </em><em>vivo.</em></p><p><strong>Materials </strong><strong>a</strong><strong>nd</strong><strong> </strong><strong>Methods</strong><strong>: </strong>lontophoresis with methylene blue and reactive black, 1% and 3% each, was performed <em>in vitro </em>on sclera from 31 autopsy human eyes. The performance of methylene blue and reactive black was studied <em>in vivo </em>both clinically and histologically. lontophoresis of 1 eye with reactive black 3% and the fellow eye with methylene blue 3% was performed on 11 rabbits.</p><p><strong>R</strong><strong>e</strong><strong>sults</strong><strong>: </strong><em>In </em><em>vitro, </em>the creation of a full-thickness sclerostomy using a pulsed dye laser was significantly higher for reactive black <span style="font-size: 10px;">3% (71%) than for methylene blue 1% (40%) (p=0.017, </span><span style="font-size: 10px;">McNemar's test) and  methylene blue 3% (35.5%) (p=0.0078). In vivo the intraocular pressure drop (mean ± SD) was greater for reactive black 3% (-4.6±6 mm Hg) th an methylene blue 3% (-0.3 ± 12.9 mm Hg) (p=0.015, paired t-test). The frequency </span><span style="font-size: 10px;">of bleb formation, flattening of the anterior chamber, or visible subconjunctival hole was significantly higher for reactive black (82%) than for methylene blue (18%) (p=0.015 , McNemar's test). Histologic study in 14 rabbits immediately following GLS demonstrated 5 full-thickness sclerostomies in the reactive black­ stained eyes. and 2 full-thickness sclerostomies in the methylene blue-stained eyes. The difference between reactive black and methylene blue, based on histology, was not statistically significant </span><span style="font-size: 10px;">(Fisher's exact test).</span></p><p><strong>Conclusion: </strong>Reactive black is better than methylene blue for <span style="font-size: 10px;">achieving full-th ickness sclerostomy </span><em style="font-size: 10px;">in vi</em><em style="font-size: 10px;">tr</em><em style="font-size: 10px;">o</em><em style="font-size: 10px;"> </em><span style="font-size: 10px;">and </span><em style="font-size: 10px;">in </em><em style="font-size: 10px;">v</em><em style="font-size: 10px;">ivo.</em></p> ER -