5 - Choroid

Mesenchyme

The choroid and sclera are formed when the ______ proximal to the optic cup condenses into 2 layers

Week 7

During what week of development do the choroid and sclera begin forming?

Month 4-7

The choroidal stroma develops together with the rest of the uvea during

Neuroectoderm

The iris and ciliary body are derived from the anterior rim of the optic cup also known as :

Neuroectoderm

The iris sphincter and dilator muscles are derived form :

Neural crest cells

The cilairy muscle is derived from

Neuroectoderm

The iris and clary body epithelium come from the _____ during development

1/5

The iris and the ciliary body contain the anterior ____ of the optic cup.

RPE and neural retina

What layers in the posterior segment share an embryonic origin with the epithelial layers on the iris and ciliary body?

Optic nerve to ora serrata/ciliary body

The choroid spans from the _____ to the ______

Mesoderm and Mesenchyme of the neural crest

The choroid is derived from _____ and _______

True

T/F : The choroid provides blood supply to the outer retina via the choriocapillaris

Prevent oxidative damage

The choroid dissipates heat from photoreceptor activity in order to

False

T/F : Choroidal defects do not cause degenerative changes and neovasularization in the retina

Retina

Label : A

Choroid

Label : B

Sclera

Label : C

Iris, ciliary body, choroid

What makes up the vascular tunic (uvea)?

True

T/F : The pigmented layer of the choroid contains abundant melanocytes of neural crest origin

Choroidal Nevus

Benign accumulation of melanocytes within the choroid

Choroidal vasculature is visible

How would a fundus image appear in a patient with albinism?

True

T/F : Patients with albinism have an absent fovea

Blood supply/waste removal, thermoregulation, conduit, light absorption, response to IOP changes, aqueous drainage, and secretion of growth factors

What are the 7 functions of the choroid?

Ocular perfusion pressure

What is OPP?

Decrease

As OPP increases, choroidal blood flow will _________

Increase

As OPP decreases, choroidal blood flow will __________

Choroid

What is the most posterior structure of the uveal tract?

At the level of the optic nerve and where the vortex veins emerge

At which points do the choroid attach to the sclera?

True

T/F : The choroid is firmly attached tp the RPE via Bruch's membrane

The macular area

Where is the choroid the thickest?

Posteriorly

Is the choroid thicker anteriorly or posteriorly?

Posterior

The choroid is located _____ to the pars plana of the ciliary body

Pars plicata

Label : A

Pars plana

Label : B

Ora serrata

Label : C

Choroid

Label : D

Sclera

Label : E

RPE

What retinal structures are continuous with the pigmented epithelia of the ciliary body?

Neural retina

What retinal structures are continuous with the non-pigmented epithelia of the ciliary body?

Short posterior ciliary arteries

Where does the choroid receive most of its blood supply from?

Three

How many layers of blood vessels are there in the choroid?

Haller's layer

Layer with larger-sized venues and arterioles :

Sattler's layer

Layer with medium sized blood vessels

Choriocapillaris

Layer with small capillaries in apposition to Bruch's membrane

Non-fenestrated

Are Haller's and Sattler's layers fenestrated or non-fenestrated?

Fenestrated

Is the choriocapillaris fenestrated or non-fenestrated?

True

T/F : The 3 vascular beds of the choroid have no significant anastomosis with other structures

Segmental

The vascular beds of the choroid have _____ distribution

Bruch's membrane

What is the innermost layer of the choroid?

True

T/F : Bruch's membrane has direct contact with the RPE

Choriocapillaris

What is the second most innermost layer of the choroid?

Choroidal stroma

What is the second most outermost layer of the choroid?

Loose connective tissue

The choroidal stroma consists of

Choroidal stroma

Sattler's layer and Haller's layer make up the

Suprachoroidea (Epichoroidea)

What is the outermost layer of the choroid?

Bitches can't stand hot saunas

What is the pneumonic to remember the layers of the choroid from innermost to outermost? (BCSHS)

True

T/F : RPE cells will remain attached to the choroid if there is a retinal detachment

Basement membrane of RPE cells, inner collagenous zone, elastic layer, outer collagenous zone, discontinuous basement membrane of the choriocapillaris

What are the 5 layers within Bruch's membrane?

Type IV

What is the most abundant type of collagen in Bruch's membrane?

Bruch's membrane

What layer of the choroid contributes to the outer blood-retinal barrier?

Pericytes and glial cells that surround the non-fenestrated retinal capillaries

The inner blood-retinal membrane is made of

Drusen

Accumulations of lipofuscin underneath the RPE and above the choroid

Dry AMD

The presence of Drusen is an indicator of what eye disease?

Unknown

What is the etiology of Drusen?

Wet AMD

Choroidal neovasularization is an indicator of what eye disease?

VEGF (vascular endothelial growth factor)

Choroidal neovasularization is a result of an excess of _______

Retinal detachment

The sensory part of the retina separates from the RPE

Retinal tear

Most retinal detachments are secondary to a __________

Accumulation of fluid between the RPE and neuroretina

Most retail detachments are caused by

A shadow or curtain sensation

What is the telltale sign a patient reports when they are experiencing a retinal detachment?

False

T/F : All retinal tears become retinal detachments

Short posterior ciliary arteries

The choriocapillaris is mainly derived from what arteries?

Vortex veins

What veins are drained but he choriocapillaris?

Macular area

The choriocapillaris is thickest in the ________

End arteries

The choriocapillaris is organized in a hexagonal shape and are considered _______

Changes in IOP

The choriocapillaris maintains a high pressure circulation to resist collapse from

Choroidal ischemia

Which disease is a result of defects in the short posterior ciliary circulation or choroidal vascular beds?

Dark hexagonal patches

How does choroidal ischemia present in fundus and FA?

Loose connective tissue and 2 vascular layers

The choroidal stroma is made of ______ tissue and ___ vascular layers

Haller's layer and Sattler's layer

What are the vascular layers within the choroidal stroma?

True

T/F : SPCA's and ciliary nerves travel throughout the suprachoroidal space

False

T/F : The vascular beds within the choroidal stroma are fenestrated

Pterygopalatine and superior cervical ganglia

Autonomic fibers from _____ and _________ run within the choroidal stroma

Type I

What type of collagen is most abundant in the choroidal stroma?

Fibroblasts, smooth muscle cells, immune cells, and growth factor secreting cells

What makes up the cellular components of the choroidal stroma?

Blood flow and choroidal thickness

Smooth muscle cells in the choroidal stroma receive sympathetic, parasympathetic, and nitrergic innervation to regulate _______

Secretory cells

______ cells are involved in modulation of vascularization, Bruch's membrane composition, sclera growth and remodeling

False

T/F : Choroidal pigmentation does not vary among different ethnicities

Waardenburg Syndrome

Mutation that impairs normal migration and differentiation of neural crest cells

Autosomal dominant

Waardenburg Syndrome has what type of inheritance pattern?

Waardenburg

Hypopigmentation in the uveal tract, loss of hearing, loss of skin/hair pigmentation, and heterochromia are all indicators of :

Downward growth of the medial canthi

What is dystopia canthorum?

Choroidal melanoma

Most common primary intraocular malignancy in adults

Melanocytes within the uveal tract

Where do choroidal melanomas originate from?

True

T/F : 50% of the patients with choroidal melanoma develop metastases within 15 years

Suprachoroidal / Epichoroidal space

Potential space between sclera and choroidj

Choroidal effusion

Fluid buildup in the suprachoroidal space

Suprachoroid

Pathway for neurovacular structures and possible site for pathological accumulation of fluid

LPCA and long posterior ciliary nerves

Which nerves and arteries travel through the suprachoroid to reach the front of the eye

Choroidal detachment

Pathological accumulation of fluid in the suprachoroid space may cause :