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Miltiadis K Tsilimbaris, Roulina Niavi, Onurcan Sahin, Chrysanthi Tsika, Irene Naoumidi; A LED based device for transscleral photodynamic ablation of the ciliary body in rabbits using Verteporfin.. Invest. Ophthalmol. Vis. Sci. 2014;55(13):6167.
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© ARVO (1962-2015); The Authors (2016-present)
To develop a LED based irradiation source suitable for transscleral photodynamic therapy of the ciliary body with Verteporfin. Transscleral ciliary body PDT using Verteporfin and a laser source has been found to result in significant alterations of the ciliary body and reduction of the intraocular pressure. LEDs have several advantages compared to laser light sources that are currently used for the excitation of Verteporfin in ophthalmic applications.
An array comprised from two deep red (690nm) 1 watt power LEDs were used in the experiment. LEDs were connected in series and driven continuously by a current limiter circuit with 700 mA (milliampere). Heat dissipation was controlled by an aluminum hand piece where LEDs were mounted on. LEDs contain an 120 degree clear lens which provides 0.6 relative intensity at the 80 degree. The array was tested in 10 albino rabbits. Eight eyes were irradiated after the injection of Verteporfin (1 mg/krg) while 10 eyes were irradiated without injecting the dye. The LEDs' lens were placed at 12 o'clock position, 1 mm behind the limbus and the eyes were irradiated 45 to 90 sec. When combined with Verteporfin, the irradiation was initiated 1 min after the completion of dye's injection. Animals survived for 24 hours and then were scarified and their eyes were prepared for light microscopy.
In eyes that were irradiated after Verteporfin injection, significant alterations were located at the ciliary body including vascular thrombosis, blood stasis and edema of the ciliary epithelium. These findings were mainly located at 12 o'clock position; less extensive changes could be located in the controlateral part of the ciliary body (6 o' clock). In animals that received maximum irradiation (90 sec.), serous retinal detachment and choroidal detachment as well as intravitreal bleeding could be seen.
An array of LED sources emitting light of suitable wavelength can effectively activate Verteporfin and induce significant PDT effect after transcleral irradiation of ciliary body. The irradiation parameters used in this preliminary study resulted in extensive histological alterations. Further manipulation of the intensity and the spatial distribution of the LED light can lead to a devise that will be useful for future experiments with transscleral PDT of the ciliary body.
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