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0:00
Hello.
My name is Rachel Gillespie.
I'm a research
associate at Manchester
Centre for Genomic Medicine
within the University
of Manchester in the UK.
0:10
Today I'm going to talk about
the molecular mechanisms
underlying development
of the ocular lens,
the physiological processes in
place to establish lenticular
transparency, and the genes
and proteins important in each
of these processes.
I will also discuss the genetic
basis of lens abnormalities,
current approaches to the diagnosis
of this group of conditions,
and the utility of genetic
testing in these cases.
0:38
The vertebrate eye is
an incredibly complex
sensory organ that detects and
reacts to light to allow vision.
In this, the ocular lens is crucial.
As illustrated in
the diagram, the lens
is central to the visual process.
Located within the posterior
chamber of the anterior segment,
just behind the cornea, iris, and
trabecular meshwork of the anterior
chamber, the adult lens is
approximately 4 millimeters thick,
9 millimeters in
diameter, and comprised
of around 3,000 layers of cells.
The lens developed to form a
curved, flexible structure anchored
by the zonules of Zinn and
suspensory ligaments that
are connected to the ciliary
muscle of the ciliary body.
The ciliary muscle contracts
to make the lens more convex,
and relaxes to flatten it.
Via this changing of shape, the lens
is able to alter this optical power
to maintain clear focus on objects
of varying distance in a process
known as accommodation.
The lens also plays an important
role in the refraction of light.
Whilst the majority of
refraction takes place
at the air-cornea
interface, the lens
is responsible for fine-tuning
light refraction for accurate
focusing onto the macula within
the retina for detailed vision.
To facilitate this,
the lens has evolved
a specialized and complex
microarchitecture that absorbs
a minimal amount of light
visible to the human eye
by preventing light scatter.
This enables the establishment of an
unparalleled level of transparency
and a high refractive index.
