Quantitative fluorescein angiography following diode laser retinal photocoagulation

✍ Scribed by Mordon, Serge; Desmettre, Thomas; Devoisselle, Jean Marie

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 325 KB
• Volume: 24
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/(sici)1096-9101(1999)24:5<338::aid-lsm4>3.0.co;2-i

✦ Synopsis

Objective: An in vivo study was done to establish if laserinduced damage of the retina could be quantified using fluorescein angiography. Method: This study was carried out on rabbit eyes (n = 6) with an 810 nm diode laser (spot diameter: 500 m, pulse duration: 1 second, power: 100 mW-400 mW) adapted on a slit lamp. Fluorescence measurements were performed with a fundus camera connected to a fluorescence imaging system. Fluorescence staining of the retina was evaluated by mathematical modeling. Lesions were correlated to laser parameters and to histologic data.

Results

: Image analysis shows that the laser lesions stained progressively. Fluorescence appears first at the borders of the lesion exhibiting a fluorescent ring. A progressive increase of the fluorescence into the central zone is observed. The maximum fluorescence intensity into the center of the laser spot is obtained after a delay depending on the laser energy. Below 100 ± 20 mW, lesions are detectable by fluorescence imaging only. A fluorescence plateau appears for a threshold light dose above 200 ± 20 mW. Mathematical modeling demonstrates that quantitative assessment of laser-induced damage to the retina is feasible using fluorescence imaging. Conclusion: The quantification of fluorescence staining in terms of both intensity and time can contribute to a better quantification of laser-induced damage. At last, since laser damage may mimic naturally occurring pathology, this method should also be considered to quantify different types of lesions. Lasers