[Value of fluorescein angiography in control of retinal thermal damage due to diode laser].
OBJECTIVE
To evaluate on an ocular ophthalmic model the interest of digitized fluorescein angiography for a control of laser induced thermal damage.


METHODS
After anesthesia, retinal photocoagulation was performed on 6 rabbit eyes with a 810 nm diode laser (p = 100 to 400 mW, phi = 500 microns, 1s) (OcuLight, IRIS Medical Instruments Inc., USA). Fluorescein angiography was then performed with measurements of fluorescence intensity in the area of the laser exposures (CF-60UVi Canon-Europe, The Netherlands; OcuLab, Life Science Resources Ltd, England).


RESULTS
Image analysis shows that the laser lesions stained progressively. For dosages up to 100 +/- 20 mW fluorescence intensity at the center of the laser spot could be modelized with: Icentrer = Imax [(1-e-alpha t)]-Ce beta t with alpha = 0.2 (s-1), beta = 0.46 (s-1); Imax 230 and C = 0.92. For dosages superiors to 200 +/- 20 mW the modelization was: Icenter = Imax [(1-e-alpha t)] with alpha = 0.2 (s-1 and Imax = 230.


CONCLUSIONS
This study demonstrates that quantitative assessment of laser-induced damage to the retina is feasible using fluorescence imaging. The quantification of fluorescence staining in terms of both intensity and time can contribute to a better quantification of laser-induced damage.
Desmettre
T
T
Centre Ophtalmologique d'Imagerie et Laser, Lambersat. desmettre@lille-inserm.fr
Devoisselle
J M
JM
Soulie-Begu
S
S
Mordon
S
S
D000818:Animals; D001813:Blood-Retinal Barrier; D005451:Fluorescein Angiography; D006358:Hot Temperature; D017075:Laser Coagulation; D007834:Lasers / Q000009:adverse effects*; D008962:Models, Theoretical; D011817:Rabbits; D012160:Retina / Q000293:injuries* / Q000601:surgery*; D013997:Time Factors