P 216 Calcium distribution in the human lens
نویسندگان
چکیده
m To IIIthe absorption we&km a, expressed in cm.‘. of a 2940 nm infrared radiation through ndcmxctions of human and porcine lenses. m Human lens nuclei from extracapsulwly cataract pmcedures and porcine lens from freshly enucleakd porcine eyes were crycat in IO, 15 and 30 pm sccdons. The crymctions were placed on micmsopc slides and covered by cover slips, whose edgs were painted with unmloured nail varnish to reduce bioliogical water evaporation. The slides were placed into the microbeam of a Fourier Transform ISpectmphotometer Nimlet 20 SXC to measure the variations of tissue absmban~ versus wwelength between 1750 and 4750 nm The: ~F&IWU obtakd varies in shape and intensily according to the samples hydration degree. A mathematical approach using biological water and dry lens material spectra allows the “lcamrcnlcnt of tissue absorbance at 2940 nm acxordh~g to the samples hydration degree. The absorption coefficient a is obtained dhiding ababance value at 2940 nm by minos&tion Lhichess expressed in centimeter m Absorption spcctrw of dry tissue shows 5 peaks at 3049, 3249,3377,3408 and 3478 nm with a maximum at 3049 nm. Huw~ absorption coefficient a1 2940 nm varies from 344 * 127 cm-’ in dry lens nuclei to 636 * 236 cam in fully hydrated samples Porcine coefiicient varies from 698 * 143 cm-’ (dry tissue) m 1291 f 265 cm-l (hydrated samples). Conclusions At 2940 MI, Ihe lens absorption cxMicmu increases with tissue water content and makes Er:YAG laser particularly useiid in cataract surgery. Kev-words Human nuclei, porcine lens, infrared spectrophotometry, absorption me5cient, Er:YAG laser, cataract surgery.
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عنوان ژورنال:
- Vision Research
دوره 35 شماره
صفحات -
تاریخ انتشار 1995