LECTURE 6.2: POSTERIOR CHAMBER AND VITREOUS HUMOR

Posterior chamber

this is the space or the area behind the iris.

posterior surface of the iris

Posterior chamber is bounded anteriorly by the?

the ciliary body

Posterior chamber laterally bounded by the?

anterior surface of the crystalline lens and zonules of zinn

Posterior chamber is posteriorly bounded by the?

Posterior chamber

this is the area where the aqueous humor is secreted from the ciliary body

anterior chamber

before it goes to the ___ ______, the aqueous humor stays in the posterior chamber before it drains in the anterior chamber by the filtration apparatuses (Schlemm’s canal and Trabecular Meshwork).

posterior chamber

Ciliary processes that secrete the aqueous humor project into the?

POSTERIOR CHAMBER

An annular area located behind the iris and bounded by the posterior iris surface, the equatorial zone of the lens, the anterior face of the vitreous and the ciliary body

internal limiting membrane of the nonpigmented epithelium of the ciliary body

Zonule fibers arise from the _____, pass through the posterior chamber and insert into the lens capsule

zonule fibers

When you say _____ ____, they are actually talking about the ciliary ligaments or the zonules of zinn. These are ligaments that connects the ciliary body to the crystalline lens.

Canal of Hannover and Canal of Petit

Two regions of the posterior chamber

CANAL OF HANNOVER

Area occupied by the zonules

CANAL OF PETIT

RETROZONULAR SPACE; the area from the most posterior zonules to the vitreal face.

primary, secondary, and tension.

SUSPENSORY LIGAMENTS is divided into three. What are these?

PRIMARY LIGAMENTS

These are the fibers connected to the crystalline lens.

TENSION LIGAMENTS

These are the fibers attached to the ciliary body.

SECONDARY LIGAMENTS

These are the fibers that connect the primary zonules and tension zonules with each other.

VITREOUS CHAMBER

Filled with gel-like vitreous body

VITREOUS CHAMBER

Occupies the largest portion of the globe

VITREOUS CHAMBER

Also largest chamber in the eye

posterior surface of the lens, retrozonular portion of the posterior chamber

Vitreous chamber is bounded on the front (anteriorly) by the _______ and the _________

pars plana of the ciliary body and retina

Vitreous chamber peripherally it is bounded by the _______

retina, optic disc

Vitreous chamber posteriorly it is bounded by the _______ and ______

patellar fossa

Center of the anterior surface of vitreous chamber contains the ____ ______, an indentation in which the lens sits

vitreous humor

The vitreous chamber is the one that contains the ____ _____, this substance is basically water, and it has the same index refraction with water which is 1.33

jelly

Vitreous humor is kind of ____.

watery

the aqueous humor is _____.

It allows light to pass through it.

Main function of the vitreous chamber is?

It is one of the four important refractive media of the eye.

ora serrata

Vitreous base located at the ___ _______

ora serrata

When there is a vitreous detachment, this will be the last that the vitreous will detach.

Posterior lens; Optic Disc; Macula; Retinal Vessels

Other vitreous attachments are the?

ora serrata, retinal vessels

The __ ________ is the strongest attachment while the ___ ______ are the weakest attachment.

internal limiting membrane

Attachment of the vitreous to retinal blood vessels consists of fine strands that extend through the ________ to branch and surround the larger retinal vessels

hemorrhages

Strands may account for ________ that occur when there is vitreal traction on the retina

Vitreous Base

Most extensive adhesion

1.5, 2

Vitreous Base extends ___ to ___ mm anterior to the ora serrata, 1 to 3 mm posterior to it and several mms into the vitreous

1, 3

Vitreous Base _ to _ mm posterior to it and several mms into the vitreous

Ora serrata

__ _______ has the most extensive adhesion

Vitreous Base

Vitreal fibers that form the base are embedded firmly in the basement membrane of the nonpigmented epithelium of the ciliary body and the internal limiting membrane of the peripheral retina

Hyaloideocapsular Ligament of Weiger or Retrolental Ligament

Forms an annular attachment 1 to 2 mm wide and 8 to 9 mm in diameter between the posterior surface of the lens and the anterior face of the vitreous

diminishes

Retrolental Ligament have Firm attachment site in young persons but the strength of the bond _____ with age

optic disc

Peripapillary adhesion around the edge of the ___ ____ also diminishes with age

3, 4

Annular ring of attachment at the macula is to mm in diameter

vitreous cortex, intermediate zone, center zone

The vitreous can be divided into zones that differ in relative density. What are these?

vitreous cortex

The vitreous can be divided into zones that differ in relative density. The outermost zone is the ___ ______,

intermediate zone

the ______ is inner to the cortex

center zone

and the ____ _____ is occupied by Cloquet’s canal.

hyaloid surface

also called the ____ _____, is the outer zone.

Vitreous Cortex (Outer Zone)

It is 100μm wide, and it is composed of tightly packed collagen fibrils, some of which run parallel and some perpendicular to the retinal surface.

Vitreous Cortex (Outer Zone)

Anterior cortex lies anterior to the base and is adjacent to the ciliary body, posterior chamber, and lens

Vitreous Cortex (Outer Zone)

Posterior cortex extends posterior to the base and is in contact with the retina

TRANSVITREAL

Vitreous Cortex contains ______ CHANNELS

prepapillary hole, the premacular hole, and prevascular fissures

What are the transvitreal channels?

PREPAPILLARY HOLE

sometimes be seen clinically when the posterior vitreous detaches from the retina

PREMACULAR HOLE

weak area, may be a region of decreased density rather than an actual hole

PREVASCULAR FISSURES

provide the avenue by which fine fibers enter the retina and encircle retinal vessels

Contains fine fibers that are continuous and unbranched and that run anteroposteriorly

Arise at the region of the vitreous base and insert into the posterior cortex

Peripheral fibers

____ ______ parallel the cortex, whereas the more central fibers parallel Cloquet’s canal

Cloquet’s Canal

Also called the HYALOID CHANNEL or the RETROLENTAL TRACT

Cloquet’s Canal

This is in the center of the vitreous chamber or crosses

Cloquet’s Canal

Located in the center of the vitreous body

Cloquet’s Canal

Has an S shape, rotated 90 degrees with the center dip downward

Cloquet’s Canal

Former site of the hyaloid artery system, which are formed during embryologic development

Cloquet’s Canal

Arises at the retrolental space

Cloquet’s Canal

Anterior face is approximately 4 to 5 mm in diameter

MARTEGIANI

Cloquet’s Canal terminates at the area off ________

MARTEGIANI

A funnel shaped space at the optic nerve head that extends forward into the vitreous to become continuous with the canal

98.5 – 99.7% water and has connective tissue status and being an extracellular matrix

COMPOSITION OF VITREOUS

SALTS, SOLUBLE PROTEINS, HYALURONIC ACID

Highly transparent vitreous is a dilute solution of ____, _____ ______ and _____ _____contained within a meshwork of the insoluble protein collagen.

vitreous base, posterior cortex, anterior cortex, center

Collagen is highest in the ____ ____, next highest in the ____ ______, next in the ____ _____ and lowest in the ____

Collagen

One of the reason why the vitreous humor is jelly.

Second major vitreal component

Long unbranched chain of molecules coiled into a twisted network

Macromolecule maintains the wide spacing between fibrils

posterior cortex

Concentration of HA is highest in the ____ ____ and decreases centrally and anteriorly

Hyalocytes

VITREOUS CELLS is also known as?

Hyalocytes

Located in a single, widely spaced layer in the cortex near the vitreal surface and parallel to it

Hyalocytes

Synthesize HA, glycoproteins for the collagen fibrils or have phagocytic properties

SHOCK ABSORBER

Vitreous chamber acts as a “____ ______” protecting the fragile retinal tissue during rapid eye movements and strenuous physical activity

Vitreous body

____ _____ is a storage area for metabolites for the retina and lens and provides an avenue for the movement of these substances within the eye

Vitreous body

Transmits and refracts light, aiding in focusing the rays on the retina

Disruption in the HA collagen complex

________ causes the collagen fibrils to aggregate into bundles which may become large enough to be visible clinically (FLOATERS)

A very homogenous gel like body

AGE-RELATED VITREAL CHANGES:

IN THE INFANT

Gel volume decreases and the liquid volume increases

AGE-RELATED VITREAL CHANGES:

WITH MATURATION, CHANGES OCCUR

Vitreous is 80% gel and 20% liquid

AGE-RELATED VITREAL CHANGES:

BY AGE 40 YEARS

50% liquid with most of the liquefaction occurring in the central vitreous

AGE-RELATED VITREAL CHANGES:

BY 70 OR 80 YEARS

• HA pools forming areas of liquid vitreous

• Macromolecule moves out of the collagen network, causing fibrils to coalesce into fibers then bands

As the dissolution of the HA collagen complex occurs