Registration for a live webinar on 'Chronic inflammation, immune cell trafficking and anti-trafficking agents' is now open.See webinar details
Lens development and disorders - molecular biology and genetics
Published on May 31, 2016 41 min
Other Talks in the Series: Biology of the Eye
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.
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.
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.