Authors
Bubnova I. A.
Med.Sc.D., leading research associate1
Semchishen V. A.
Ph.D., leading research associate2
Sviridov A. P.
Ph.D., leading research associate2
Khaydukov E. V.
senior research associate2
Novikov I. A.
senior research associate1
Petrov S.Yu.
Ph.D., leading research associate1
Pakhomova N. A.
Postgraduate student1
Volzhanin A. V.
resident1
1 - Scientific Research Institute of Eye Diseases, 11 A,B, Rossolimo St., Moscow, Russian Federation, 119021
2 - Institute of Photonic Technologies of Federal Research Centre «Crystallography and Photonics» of Russian Academy of Sciences, 2 Pionerskaya str., Troitsk, Moscow, Russian Federation, 142190
Abstract
Aim. To develop a non-contact photoluminescent diagnostic method for the fibrous tunic of the eye.
Methods. Mechanical stress of eye fibrous tunic equal to 50 mmHg was induced in a deepithelized rabbit eye. In these conditions a Flurolog-3 spectrophotometer (Jobin-Yvon, France) was used to measure cornea and sclera photoluminescence excitation spectra in with 250, 350 and 450 nm wavelengths and photoluminescence excitation spectra within the 300-425 nm wavelength range. Cross- and co-polarized photoluminescence spectra induced with linearly polarized light with 450 nm wavelength were also acquired.
Results. Maximal corneal photoluminescence excited at 350nm wavelength approaches 450nm. Meanwhile, photoluminescence spectrum can be presented as two bars: pyridine nucleotide with its maximum at 460-470nm and glycated collagen at 430-440nm. Epithelium contribution is shown to be substantial. The difference of photoluminescence spectra with and without epithelium is defined by luminescence of riboflavin that has two absorption bands with maximums at 450 and 365nm. Corneal luminescence spectrum excited at 450nm wavelength has a maximum nearing 540nm, that coincides with the spectrum of fluorophores localized in epithelium and endothelium. Luminescence spectrum excited at 250nm wavelength corresponds with the spectrum of tryptophane, that is present in the intraocular lens.
Corneal photoluminescence induced with polarized light is partly polarized with degree of polarization equaling 0.2-0.35 and dependent on luminescence wavelength.
Conclusion. Corneal photoluminescence yield is maximal at 330-350nm excitation light wavelength. Eye photoluminescence induced with linearly polarized light is partly polarized. The degree of corneal photoluminescence polarization induced with linearly polarized light can be calculated to assess the physiological state of the eye.
Key words
cornea, sclera, eye fibrous tunic, luminescence, polarization, elasto-optic effect, collagen
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