Optics laboratory

 

Description

The optics laboratory is equipped with solid basic optical and photometric equipment and can be completely darkened. This laboratory is primarily used for research work and questions relating to the technical implementation of the objective measurement of scattered light in the eye.

 

Laboratory equipment:

  • Blackout system
  • Optical table (passively damped)
  • Optical components (lenses, filters, mirrors), mechanical and piezoactive components (holders, mounts, linear one-, two- and three-axis drives, etc.)
  • Hartmann-Shack sensors for analyzing wave fronts
  • Powermeters of various measuring apertures to determine the laser power
  • Beam profiler for determining and measuring the laser beam quality
  • C-Quant scattered light measuring device
 

Example application

The objective measurement of scattered light in the human eye can be carried out using a Hartmann-Shack wavefront aberrometer. The point image functions of the subapertures of the microlens array are analyzed. The imaging angle of a conventional system is very small. A measurement principle was developed at the BMTI and a reconstruction algorithm for the PSF was established to overcome this limitation. The fixed aperture for suppressing reflected and scattered light was replaced by a variable aperture. Its effectiveness was investigated in a proof-of-principle study on eight healthy volunteers. Stray light filters were placed in front of the eyes to simulate stray light. The calculated stray light parameter was compared with C-quant measurements and the filter values. A PSF parameter shows a strong correlation with the density of the filters and a linear relationship with the C-quantum scattered light parameter. With the new measurement and reconstruction techniques, it became possible to achieve an objective scattered light analysis of viewing angles up to 4 degrees of visual angle.

TU Ilmenau
Figure 1 shows the process of calibrating the system for generating and evaluating plane wave fronts.