Hi, I am Dr Thomas Whitelaw, welcome back to Espisode 65 of Basic Sciences in Ophthalmology.In thiks episode we're exploring one of the most remarkable abilities of the human visual system: the ability to see in darkness.

Imagine walking out of a brightly illuminated room into a dark garden.

At first, you can barely distinguish the objects around you.

Gradually, however, shapes begin to emerge. You become aware of movement,outlines and objects that were initially invisible.

Your eyes have not simply become accustomed to the darkness.

A complex series of biochemical, physiological and neural changes has occurred within your visual system.

At the centre of these changes are the rod photoreceptors, the specialised retinal cells responsible for vision at low levels of illumination.

The process by which visual sensitivity increases afterentering darkness is known as dark adaptation.

And when the rod system or its supporting pathways become dysfunctional, patients may experience nyctalopia, commonly called night blindness.

Today, we'll explore three interconnected subjects:

First: rod photoreceptors.

Second: dark adaptation.

And third: disorders affecting night vision.

We'll examine the anatomy, physiology, biochemistry and clinical consequences of these systems, using exclusively the ophthalmology textbooks uploaded for this podcast project.

Hi, I am Dr Thomas Whitelaw, welcome back to Espisode 64 of Basic Sciences in Ophthalmology.In Episode 64, we're exploring a fascinating and clinically important area of ophthalmology: the anatomy of orbital trauma.

The orbit is much more than a bony cavity containing the eye.

It is a complex anatomical structure containing the globe, extraocularmuscles, nerves, blood vessels, orbital fat and connective tissues.

Its walls provide protection, but their thickness and anatomicalrelationships also create areas of vulnerability.

When the orbit is injured, understanding these relationships becomesessential.

A fracture of the orbital floor can trap an extraocular muscle and producedouble vision.

An infection spreading from the paranasal sinuses can involve the orbitaltissues and threaten sight.

And modern imaging allows us to investigate structures that cannot beassessed adequately through clinical examination alone.

Today, we'll examine three interconnected subjects:

First: blowout fractures.

Second: orbital cellulitis.

And third: imaging in trauma.

Hi I am Dr Thomas Whitelaw, welcome back to Basic Sciences in Ophthalmology.

In Episode 63, we're exploring one of the most mechanically fascinating regions of the eye: the vitreoretinal interface.

The vitreous is often thought of simply as the transparent gel filling the posterior segment. But the relationship between the posterior vitreous cortex and the retinal surface is dynamic. It changes with age, and the way in which the vitreous separates—or fails to separate—from the retina can have major consequences for vision.

At the macula, persistent attachment can generate vitreomacular traction.

Cellular proliferation on the retinal surface can produce an epiretinal membrane.

And with ageing, liquefaction and collapse of the vitreous can eventually produce a posterior vitreous detachment, or PVD.

These are not completely separate processes. The uploaded Yanoff text describes vitreomacular traction, epiretinal membrane and several other macular disorders as part of a spectrum related to variations in anomalous posterior vitreous detachment.

So today we'll examine three interconnected processes:

First: vitreomacular traction.

Second: epiretinal membranes.

And third: posterior vitreous detachment.