Figure 7
(A) Confocal fluorescence microscope F410. The excitation beam of a 405 nm single mode fibre-coupled laser diode (LP405-SF10, Thorlabs, NJ. USA) is first split into the 30:70 (R:T) proportion by the beam splitter before being reflected by a dichroic mirror (cut-on 425 nm). The light is then being collimated by an achromatic doublet lens (f = 200 mm) and focused on the sample by an achromatic doublet and meniscus lens combination (f = 47.11 mm) mounted on a motorised translation stage (SMAC Europe, UK). Fluorescence and scattered signals collected from the sample by the scanning and collimating lenses are separated by the dichroic mirror. The scattered and fluorescence signals are focused onto a photo diode (PDA36A-EC, Thorlabs) through a 150 μm pinhole a photomultiplier tube module (H9306-04, Hamamatsu) through an emission filter (cut-on 450 nm) and a 50 μm pinhole respectively. Laser intensity is measured using the 70% portion of the excitation beam by a photo diode (PDA100A-EC, Thorlabs). Digitized by an analogue-to-digital converter (ADC) (USB-1208FS, Measurement Computing, MA, USA) intensities of the fluorescence and scattered light signals were normalised on the excitation intensity by the instrument software and plotted as functions of scanning lens position (Z). (B) Fluorescence intensity distribution profile along the optical axis carried out in a in a donor eye lens with age related nuclear cataract correlate with increased optical density in the nucleus. (C) Density of the yellow coloration increases towards the nucleus. (D) The experimental geometry of the fluorescence intensity distribution measurements.
