Adjustment of PDT and TTT Treatment Parameters in Eyes with Lens Opacification An Experimental Study
Höh H.1, Marzelin S.2, Methling D.2, Rehfeldt K.1
1Augenklinik im Dietrich-Bonhoeffer-Klinikum Neubrandenburg; 2Fachbereich Feinwerktechnik/Augenoptik, Fachochschule Jena
Purpose: The aim of this study is to measure the change of transmission due to eyelens opacification in the spectral range of the photodynamic therapy (PDT) and transpupillary thermotherapy (TTT). Until now, there are hardly quantitative data.
Method: In a special holder, the transmission of ten clear (T0) pig eyelenses is measured with the spectrograph SPECTRO 100 Optical Spectrum Analyzer (Instrument Systems Co.) and set to 100 %. The clear lenses are given microwave treatment in four standardized steps (each with a power of 470 W for 2,5 minutes, each in a microwave oven Panasonic NN-K151W). Hereby, four determined grades of cataract could be achieved (T1 to T4); grade 4 (T4) means a complete white cataract. The measurements of the transmission are repeated immediately after establishing the several cataract grades and the reduction of transmission is assessed in comparison to the baseline transmission (1).
Results: For the PDT wavelength (689 nm) the results are as follows: T0: 100 %, T1: 72.0 ± 7
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