Purchase this article with an account.
Zhaohua Yu, Konstantin Galichanin, Karl Schulmeister, Per Söderberg; Evolution Of Ocular Temperature After In Vivo Exposure To 1090 nm Infrared Radiation And Association To Light Scattering. Invest. Ophthalmol. Vis. Sci. 2011;52(14):1556.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To determine the evolution of temperature in the eye after in vivo exposure to 1090 nm radiation. Further, to elucidate if the temperature induced by the exposure is associated with an immediate onset of light scattering in the lens, indicating thermal damage.
20 six-weeks-old albino SD rats were anesthetized and the pupils were bilaterally dilated prior to experimental exposure. The animals were divided into two groups of 10. All animals were unilaterally exposed to 6.2 W coherent infrared radiation at 1090 nm with a spot size of 2 mm within the dilated pupil for 8 s (1.6 kJ/cm2). The beam was divergent on the cornea generating a close to collimated beam between the lens and the retina to minimize retinal heating. In one 5 sensors group, temperature was recorded with thermocouples placed at the limbus, in the vitreous just behind lens and on the outer sclera next to the optic nerve in the exposed eye. In the contralateral not exposed eye, temperature was recorded at the limbus and on the outer sclera next to the optic nerve. In the other 4 sensors group, one thermocouple was placed at the limbus and another thermocouple on the outer sclera next to the optic nerve, on both eyes. Temperature was recorded during the exposure. The rats were sacrificed immediately after the exposure and both lenses were extracted by a posterior approach for light scattering measurements.
The temperature increased exponentially as a function of time asymptotically approaching a maximum. In the five-sensors group, the average temperature rise in the exposed eye was at the end of the exposure at the limbus 11 ºC, in the vitreous behind lens 16 ºC and on the sclera next to the optic nerve 15 ºC. In the four-sensor group, the temperature elevation in the exposed eye was at the end of the exposure 9 ºC at the limbus and 26 ºC on the sclera next to the optic nerve. No temperature increase could be demonstrated in the contralateral not exposed eyes. Immediately after the exposure, there was no increase of light scattering in the lenses from the exposed eyes.
An irradiance of 197 W/cm2 of 1090 nm on the cornea for 8 s (1.6 kJ/cm2) induces a temperature increase of about 10 °C in the anterior segment of the eye and about 25 °C in the posterior segment of the eye. At a temperature increase of 10 °C in the anterior segment, the lens remains clear immediately after the temperature increase, thus indicating that no immediate thermal effect occurs in the lens.
This PDF is available to Subscribers Only