Vacancies and career opportunities

Frank Schaeffel // Job description:

ESR (1 X PhD Students) (36 months)
Aim: To describe the effects of peripheral defocus on refractive development and eye growth in animal models (chicken) and on accommodation and visual performance (in humans).
Methods: Chickens are reared with lens that have a gradient across the visual field in optical power. Refraction across the visual field is measured with photorefraction and simultaneous gaze tracking. Eye shapes are measured in excised globes by video biometry. Models will be developed to predict refraction changes with different spectacle lens types. Accommodation performance with spectacles lenses with refractive gradients is measured with photorefraction, combined with gaze and head tracking. Technologies are improved and developed in the lab, using C++ programming and image processing (extensive training is available). Lenses are supplied by the industrial partner in the RTN.
Candidate profile: background in physiological optics and/or biology and/or physics.

ER (Post Doc) (18 months)
Aim: Myopic defocus imposed to the periphery of the visual field is believed to inhibit the progression of myopia. However, it is not know how such defocus would affect visually guided behaviour, accommodation and visual performance. The aim of the research is to find out how monocular and binocular peripheral defocus changes these variables in young human subjects. Always when eye growth is inhibited by a positive lens, the transcription factor ZENK is consistently and rapidly up-regulated in glucagon amacrine cells in chicks. We want to find out whether ZENK/Egr-1 represents indeed an inhibitory signal for axial eye growth also in mammals (mice) and which genes are controlled by this transcription factor in vivo. Methods: Accommodation measurements and gaze tracking in humans will be done using customized photorefractors and gaze trackers in the lab. Contrast sensitivity, contrast adaptation and visual acuity in the periphery with defined amounts of defocus will be measured by psychophysical procedures. The influence of different periods of deprivation on axial length and refraction in wildtype mice, homozygous Egr-1-/- and heterozygous Egr-1+/ knock-out mice shall be measured using low-coherence interferometry and photoretionscopy, respectively. Messenger RNA shall be extracted from knockout animals and wildtype mice and hybridized to Affymetrix GeneChip Mouse Genome 430 arrays. Differential gene expression shall be confirmed by real-time PCR. Candidate profile: The candidate should have a background in human visual physiology and physiological optics and must have previous research experience, as documented by publications. Interest in computer programming, bioinformatics and new methods of molecular biology would be advantageous, but training can be offered. Either biologists or visual psychophysicists would be appropriate.