Abstract
Purpose :
To evaluate the retinal and choroidal vasculatures using the near-infrared two-photon laser scanning ophthalmoscope.
Methods :
A compact femtosecond laser with 50 MHz repetition rate, 270 fs pulsewidth, 780 nm central wavelength, with a tunable output power up to 500 mW was used as a light source for two-photon imaging. The Brown Norway rats with jugular vein catheterization were used in this study. The indocyanine green dye (IC-GREEN with sterile aqueous solvent) was injected through the catheter to monitor the choroidal circulation. Furthermore, the mixture of fluorescein (10% AK-FLUOR, Akron) and indocyanine green dye was administered in a single injection to characterize the retinal and choroidal vessels. The dosages of dyes were administered according to the rat’s body weight.
Results :
The choroidal vasculatures were clearly seen using the two-photon Indocyanine green angiography (ICGA). The simultaneous fluorescein angiography (FA) and ICGA characterized the retinal and choroidal vessels with a single injection. The video of the two-photon FA and two-photon ICGA was recorded to capture the immediate effect of the FA and ICGA flow through the vessels. The retinal vessels and capillaries were seen immediately after the injection, and later the choroidal vessels were distinct. The simultaneous FA and ICGA using two-photon ophthalmoscope offers longer duration of effective time than the two-photon FA. The early-phase to late-phase of the angiograms were recorded. The ICGA followed by FA, and FA followed by ICGA was evaluated as well.
Conclusions :
The retinal and choroidal vessels can be acquired in a real-time scanning with a single light source, and no additional filters for FA or ICGA are needed. The combination of FA and ICGA using the two-photon ophthalmoscope will help researchers to characterize the phenotype of retinal diseases in animal models, and also to classify the type of choroidal neovascularization (classic, occult or mixed) in age-related macular degeneration (AMD) animal models.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.