Search

Background: The absorptive and photosensitizing properties of sodium fluorescein (NaFl) injected prior to laser photocoagulation may affect the retinal laser burn threshold., Methods: Photocoagulation was performed using an argon green laser with a Volk QuadrAspheric fundus lens in three anesthetized rabbits. Using a 500um spot size and a 100msec duration, varying laser powers were delivered before and at various intervals after intravenous (i.v.) injection of NaFl., Results: Photocoagulation effects were enhanced in all subjects after fluorescein injection with threshold reduced for up to 48 hours following injection., Conclusions: The effectiveness of photocoagulation following fluorescein angiography may be underestimated, although this may be clinically insignificant since most photocoagulation procedures are performed well above threshold. Nevertheless, these data should be considered in those situations where carefully controlled threshold burns are desired. In such circumstances, it is advisable to take additional care in selecting treatment powers if fluorescein has been injected or to delay photocoagulation for a minimum of 48 hours.