Effect of atropine on the human multifocal electro-retinogram (mfERG) response to retinal defocus

Project code:  MHS005

Department

Optometry and Vision Science

Location

Auckland

Supervisor

Dr John Phillips

Excessive near work (e.g. reading) is a major risk factor for the development and progression of myopia (short-sight) in children. Atropine eye drops are currently the most effective method for inhibiting myopia progression, but the site of atropine’s anti-myopia action is unknown: it may be the retina, choroid and/or sclera. The aim of this project is to investigate the effect of atropine eye drops on the human multifocal electro-retinogram (mfERG).  Near work is associated with a lag of accommodation, which causes hyperopic defocus on the retina. It is known that hyperopic retinal defocus is also associated with a reduced amplitude of the global flash mfERG response, whereas myopic defocus causes an increase in response. A demonstration that atropine influences the mfERG response to retinal defocus would suggest that one site at which atropine exerts its anti-myopia action is the retina.

Skills

Procedures for recording and analyzing the multifocal ERG in human subjects. Optical coherence tomography (OCT) imaging of the retina and choroid.

Trend of diagnosing and managing eye conditions by general practitioners in NZ

Project code:  MHS009

Department

Optometry and Vision Science

Location

Auckland

Supervisor

Robert Ng

This project will involve inviting general practitioners to complete an anonymous questionnaire online asking them their habits in diagnosing and managing eye conditions.

By understanding these trends, we can optimise the triaging of patients and tailor continuing medical education (CME) content for G.Ps

Skills

  • Designing Questionnaires
  • Communication and interviewing
  • Data analysis and report writing
  • Critical analysis

How do changes in geometrical complexity and landmark of the crystalline lens influence its fluid dynamics?

Project code:  MHS033

Department

Optometry and Vision Science

Location

Auckland

Supervisor

Ehsan Vaghefi

The crystalline lens plays an important role in allowing light to be fine focused onto the retina which allows us to perceive the world around us.
The complexity and distinct geometrical features of the crystalline lens is what allows this to happen.
We have already implemented a base model of the crystalline lens anatomy and fluid dynamics.
We are now interested in improving the model by adding more ultra-structural details of the lens anatomy.

In this project, we aim to examine how a range of different geometrical landmarks of the crystalline lens influence its fluid flow. The geometrical landmarks of interest are:

  1. Lens capsule
  2. Inner cortex barrier region
  3. Star sutures

Specific Aims

  1. To build upon the candidates’ understanding of lens anatomy and basic principle of CAD and CFD modelling.
  2. To examine how the addition of lens capsule would affect fluid flow in the lens.
  3. To examine how the alteration of the inner cortex barrier region affect fluid flow in the lens.
  4. To examine different profiles of the star sutures and how they influence fluid flow in the lens.
  5. Report on all findings with an appropriate form of documentation.

Skills

By the end of the project, the candidate will have a clearer understanding on the anatomy of the crystalline lens, the ability to design and create a 3D CAD model, as well as basic Computational Fluid Dynamics modelling principles.

Timeline

  • The candidate should consolidate their understanding of crystalline lens anatomy, basic principle of CAD modelling and Computational Fluid Dynamics in the first 3 weeks.
  • The candidate can then build on top of an existing CAD crystalline lens model by altering the geometry by adding firstly a lens capsule (5 weeks), the inner cortex barrier region (6 weeks), and finally examining different profiles of the star sutures (8 weeks) to see how each geometrical landmark influences fluid flow in the lens using the CFD model.
  • Any documentation to be completed in the last 2 weeks of the internship.

Improving children's vision screening in New Zealand

Project code:  MHS040

Department

Optometry and Vision Science

Location

Auckland

Supervisor

Nicola Anstice

Between 1 in 10 and 1 in 20 New Zealand children have some form of vision problem which, if left untreated, could affect literacy and academic performance.  Screening for vision problems in childhood is important because many children, and their parents, may not realize there is anything wrong.  Most childhood vision problems aren’t obvious – the eyes look and feel perfectly normal – but left untreated vision problems can lead to permanent visual loss which may be impossible to correct in adulthood.  Poor vision may limit future career choices such as joining the police force, becoming a pilot or even getting a commercial driver’s licence.

Children’s vision screening helps with the diagnosis of:

  • Refractive error – short-sightedness, long-sightedness and astigmatism that require correction with spectacles
  • Amblyopia (‘lazy eye’) – which can lead to permanent vision loss because the eyes and brain are not working together
  • Strabismus (‘turned eye’) – where the two eyes are misaligned.

For all of these conditions early intervention is the key to successful treatment. 

Almost all screening programmes measure vision using pictures or letters on eye charts specially designed for use with children.  In NZ we use a letter-matching chart (the Parr Vision test) and perform preschool vision screening as part of the B4 School Check.  The B4 School Check vision screen measures how well children see in the distance (4 metres) and if the results of this screening suggest a problem, the child will be referred to a specialist eye care provider for a comprehensive eye examination.  Recent evidence from overseas suggests that there may be better tests to use for children's vision screening programmes and this project aims to explore the reliability and variability of a variety of potential tests for preschool vision screening in NZ.

Skills

  • Clinical measures of visual function
  • Eye examination procedures
  • Communication skills working with different age groups
  • Information processing, evaluation and sharing
  • Data analysis and interpretation
  • Understanding the impact of research

Laser ray tracing for measurement of ocular lens gradient refractive index

Project code:  MHS044

Department

Optometry and Vision Science

Location

Auckland

Supervisor

Ehsan Vaghefi

In a series of previous experiments utilizing Magnetic Resonance Imaging the Molecular Vision Lab (MVL) has shown that the optics of the lens is actively maintained by a circulating flux of ions and water that is generated by its unique cellular physiology. In order to get a better understanding of the connection between lens physiology and optics, we need to first accurately measure such optical changes when the physiology is pharmacologically altered. In order to achieve this, the MVL has setup a custom built laser ray tracing (LRT) system that allows us to reconstruct the gradient index (GRIN) of the lens. However, this system can be improved in several ways, which are the aims of this summer studentship

1.       Further development of our newly built LRT by improving the accuracy in the extraction of data, introducing more sophisticated retrieval algorithms and streamlining overall experimental protocols

2.       Physiological challenge the lens and then measure their optical properties

3.       Improve image processing of LRT images

4.       Develop new MATLAB code for improved GRIN reconstruction

Skills

The student should have a sound knowledge of programming in MATLAB, and interested in the lab work aspect of the project as well. The ultimate goal of this research is to have an improved understanding of how changes in the ocular lens physiology will influence the optics (i.e. GRIN) of the lens.

Plasticity of jumping spider eyes

Project code:  MHS067

Department

Optometry and Vision Science

Location

Auckland

Supervisor

Dr Philip Turnbull

Background

The question of how our eyes remain in focus as it grows is important, as when it goes wrong it leads to myopia (short-sightedness) and hyperopia (long-sightedness), which need refractive correction. It was traditionally thought that a complex retina or brain was required to detect defocus, however the squid - which is an invertebrate with a simple retina - has an eye which grows in focus, which suggests that perhaps this complexity is not required. Similar 'camera-type' eyes have been found in jumping spiders, of which there are many species in New Zealand. These spiders have an even simpler nervous system, yet would seem to require an 'in-focus' eye in order to successfully hunt.

Project aims

This project would investigate how the eyes of New Zealand jumping spiders adapt to defocus. This would primarily be done by observing and quantifying their hunting behaviour. The main observation would be whether or not the spiders can adjust their behaviour to adapt to an experimental change in the focal length of their eye.

Skills

The experiment will be hands on, with the successful applicant being directly involved in the running of the experimental trails. The intent would be to conduct a concise, but complete experiment that can be published in a peer review journal.

  • Designing a controlled experiment
  • Statistical analysis
  • Captive maintenance of spiders
  • Scientific coding
  • Matlab coding
  • Literature searching

Developing a clinical test for sensitivity to facial expression

Project code:  MHS028

Department

Optometry and Vision Science

Location

Auckland

Aims

a. To quantify the interfering effect of facial expression on facial identity recognition. We will use morphed faces and determine the minimum level of identity that allows observers to reliably identify the odd-man-out face amongst two distractors (cf Dakin & Omigie, Vision Research, 2009). We will measure this "threshold identity"  for faces that are matched in expression, or that have random expressions (this is known to reduce performance). The ratio between the two thresholds is an index of an individual's susceptibility to interference from expression on face recognition ("susceptibility to expression interference": SEI).

b. To relate an individual's SEI to various personality measures of e.g. IQ, schizotypy etc, and to quantify differences in fixation strategies (measured using eye tracking)

c. To develop a new clinical test of sensitivity to facial expression based on SEI. We will measure observers' ability to locate an odd-man-out face, present amongst distractors. The odd-man-out will be defined by a difference in identity from distractors. Two versions of the test will either have all faces matched for expression (easy) or with random expressions (difficult),. Poor processing of facial expression should lead to reduced interference of expression on identity recognition and therefore BETTER performance on our test. As such it has the potential to be a superior diagnostic (e.g. for autism spectrum disorder) compared to a task that produces poor performance (which could be attributable to e.g. a general cognitive deficit or inattention). 

References

Dakin, S.C., and Omigie, D. (2009). Psychophysical evidence for a non-linear representation of facial identity. Vision Res 49, 2285-2296.

Skills

  • Visual psychophysics
  • Eye tracking
  • Working with clinical/psychiatric populations
  • Matlab programming (optional)

Ensemble coding of size: what's getting averaged?

Project code:  MHS035

Department

Optometry and Vision Science

Location

Auckland

Aims

"Ensemble coding" refers to the proceses that support our ability to make judgements of "overall" properties of multiple objects (like which bowl of apples contains fruit that are, on average, bigger). The processes supporting this ability are not well understood. We will examine peoples' ability to judge "average size" of patterns composed of mutiple elements. Our aims are to:

a. Measure local and global limits on observers' ability to judge average/overall size (ie how many elements they average, how good each sample is)

b. What are the critical determinants of their performance (element area, perimeter, brightness etc)

c. Is this process vulnerable to adaptation?

Skills

1. Visual psychophysics

2. Matlab programming (optional)