2020–2021 BCSC Basic and Clinical Science Course™
2 Fundamentals and Principles of Ophthalmology
Part I: Anatomy
Chapter 2: The Eye
This chapter includes related videos, which can be accessed by scanning the QR codes provided in the text or going to www.aao.org/bcscvideo_section02.
Hemidesmosomes anchor the basal corneal epithelial cells to the Bowman layer. Disruption at this level can lead to scarring and recurrent erosion syndrome.
In addition to housing corneal stem cells, the limbus is the site of passage of the collector channels that link the Schlemm canal to aqueous veins.
The sclera is an avascular tissue with 2 overlying vascular layers (deep and superficial) in the episclera. Clinically, episcleritis refers to inflammation in the superficial layer, and scleritis involves the deep layer.
The classification of uveitis, established by the 2005 SUN (Standardization of Uveitis Nomenclature) Working Group, is based on the primary site of inflammation within the zones of the uvea: anterior, intermediate, posterior, and all zones (panuveitis).
The blood–ocular barrier prevents extravasation of intravascular contents into the eye. It consists of intercellular junctions of adjacent cells at various locations in the eye: the blood–aqueous barrier and the blood–retina barrier (inner and outer).
Optical coherence tomography (OCT) has greatly enhanced visualization, as well as our understanding, of ophthalmic structures in the anterior and posterior segments. In addition, OCT angiography provides details of the microvasculature of the retina not previously seen on fluorescein angiography.
The retina has a dual circulation, with the inner retina perfused by the retinal vessels seen on routine examination of the fundus and the outer retina perfused by the choroid.
Excerpted from BCSC 2020-2021 series: Section 2 - Fundamentals and Principles of Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.