[Forum SIS] Seminario REPETTO (RGS & Matematica Applicata)

[Giacomo Aletti]

Con preghiera di diffusione tra tutti i possibili interessati,
scusandomi per invii multipli.
Cordialmente,
Giacomo Aletti

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Nell'ambito dei Reading Group Seminars e del Seminario di Matematica
Applicata, il giorno lunedì 9 Febbraio 2015, alle ore 14.30, nell'Aula
C (secondo piano) del Dipartimento di Matematica dell'Universita'
degli Studi di Milano, Via C. Saldini, 50, Milano,

"Aqueous humour flow in the presence of intraocular lenses"

Rodolfo REPETTO,
Department of Civil, Chemical and Environmental Engineering, University of Genoa

Abstract: Lens placement in the anterior chamber is an increasingly
popular method of correcting vision. The lens has a diameter slightly
larger than the pupil aperture, and it is placed centrally and just
anterior to the iris. The use intraocular lenses is generally very
effective and has proven to have good long term clinical outcomes.
However, the presence of the lens can lead to possible undesired side
effects, including a reduction in endothelial cell density onthe inner
corneal surface, which reduces corneal nourishing. Another possible
problem is an increase in the resistance to fluid flow between the
posterior and anterior chambers of the eye. Aqueous humour is required
to flow between these chambers and if the resistance increases
sufficiently then pupillary block could occur, meaning the pressure in
the posterior chamber increases, which could result in angle closure
glaucoma. If the risk is thought to be high the niridotomy is
typically used, in which a hole is created in the iris in order to
allow flow to by pass the pupil aperture, creating an alternative
low-resistance pathway for the aqueous humour. As well as the flow
described above, other effects can lead to flow in the anterior
chamber. Firstly, there is a temperature gradient between the inner
corneal surface and the iris and lens, depending on the difference
between atmospheric and body temperature. Combined with gravitational
effects, this leads to a buoyancy-driven flow. Secondly, the eye
performs saccades, and rotational saccades lead to accelerations and
hence flow. In addition, other movements, such as lens movement during
accommodation, rubbing the eye, and accidental impacts will lead to
flow. In this presentation we show results from a model of flow due to
pressure gradient, thermal and saccadic effects in the posterior and
anterior chambers in an eye, both with and without the artificial lens
in place. We adopt both an analytical approach based on the use of the
lubrication theory and a fully numerical model to assess the wall
shear stress on the corneal surface, the pressure drop between the
posterior and anterior chambers, with the aim of understanding how the
positioning of the lens affects these quantities. In the second part
of the talk some open issues concerning the fluid mechanics of the eye
will also be presented and briefly commented upon.


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Reading Group Seminars: The Reading Group Seminars (RGS) are organized
within an open community of researchers interested in applying up to
date mathematical modeling and data analysis approaches to the study
of biological systems. The RGS take place at the Math. Department in
Milan (via Saldini). Initiatives and updates are published on the
website: http://rgs.mat.unimi.it/.


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Giacomo Aletti, Associate Professor

ADAMSS Centre (ex MIRIAM)
Advanced  Applied Mathematical  and Statistical Sciences

Department of Mathematics (www.matematica.unimi.it)
Via Saldini, 50
20133 Milano, Italy
Tel: +39-02-503.16158
Fax:+39-02-503.16090
Cell: +39-340-9739142