Seeing Beyond lecture series 'Ophthalmic Imaging: now and into the future'

Fritz Loewe Theatre McCoy Building 253-275 Elgin Street The University of Melbourne Carlton VIC 3053

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Dr Laura Downie

Guest speakers: A/Prof Andrew Metha and Dr Christine Nguyen from the Department of Optometry and Vision Sciences at the University of Melbourne

Presentation summaries:
(1) A/Prof Andrew Metha - Looking up-close at retinal vascular structure and function – now and into the future 

Abstract: Increasing the spatial resolution of retinal imaging systems using Adaptive optics (AO) has already brought many benefits, making visible photoreceptor cells and fine elements of the human vascular tree. But enhanced spatial contrast itself is not enough to appreciate physiological processes; sequential images need to be gathered in rapid succession, using light that perturbs function in known ways if at all. We use a flood-illumination AO-ophthalmoscope equipped with a sensitive, high frame-rate areal camera to observe directly the stimulus-induced re-distribution of blood flow through the retina's narrowest vascular elements: pre-capillary arterioles, the capillaries themselves, and post-capillary venules. We've characterized the range of immediate light-induced changes of vessel diameters to confirm the action of neurovascular coupling (functional hyperaemia) at the capillary level in living humans. We've also begun to survey the pulsatile nature of individual red cell flow through single capillaries, and how this is related to cardiac output. A full characterization of pulsatility heterogeneity in normal retinas permits comparisons to be made with diseased eyes, such as in diabetes where increased cell adhesion is hypothesized from animal models.

(2) Dr Christine Nguyen - Looking beyond the eye: what the retina can tell us about the brain
Abstract: Imaging the retina has the capacity to tell us more than what is simply going on in the eye. As the retina is an extension of the central nervous system it can inform us about cortical health. This concept is familiar in vascular disease where regular optometric examinations form an essential component of diabetic management. Increasing evidence indicates this logic may extend to neurological diseases. Patients with multiple sclerosis, Alzheimer's disease and Parkinson's disease often complain of vision problems and exhibit changes to the retina that can be quantified with retinal assessment and imaging. This presentation will outline the current evidence and suggest ways in which optometrists can incorporate this knowledge into their everyday practice.

CPD points: 6 therapeutic points