BACKGROUND: Intraocular scatter is an important factor when considering the performance of the human eye as it can negatively affect visual performances (e.g. glare). However, and in contrast to other optical factors that also affect vision such as high order aberrations, there is currently no efficient method to measure accurately and objectively the amount and the angular distribution of forward light scatter in the eye. Various methods and instruments exist to assess forward light scatter (FLS) but the relation between these methods has rarely been quantified. In addition, FLS measurements obtained with existing instruments cannot be related to any physiological factors due to the absence of a valid model. PURPOSE: To investigate the relations between some of the main methods to measure forward light scatter, and to develop an experimental set -up for the objective measurement of forward light scatter that could be ideally related to physiological parameters. METHODS: After a short review of intraocular light scatter, the three main methods used to assess forward light scattering are compared. In this sense, the C-quant (CQ) straylight meter is compared to the van den Berg (VDB) straylight meter and the Hartmann-Shack spot pattern analysis obtained from the Hartmann-Shack aberrometer. The potential of the new Oculus Pentacam functionalities for providing information on backward light scatter (BLS) are also investigated. Finally, an innovative prototype for objective assessment of intraocular light scattering together with a scatter model of the eye is presented. RESULTS and DISCUSSION: Although no significant relationship was found between the different instruments considered (VDB straylight meter, CQ, Pentacam), our results allowed us to clarify some possible confusion introduced by previously published results and to illustrate the fact that existing commercial instruments such as aberrometers and the Pentacam cannot be used to measure FLS without at least some major modifications (hardware or software). Preliminary results with the prototype built in this study suggest that it could be used for the objective measurement of intraocular light scatter. Relating this measurement to physiological parameters stays however elusive, a fact that widens the future scope of this research.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:677821 |
| Date | January 2015 |
| Creators | Benito Lopez, Pablo |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.research.manchester.ac.uk/portal/en/theses/measuring-and-modelling-forward-light-scattering-in-the-human-eye(6bcbd5df-0e0b-428d-b250-30db2bb547fc).html |
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