Retina and Vitreous

Slide 1 · Retina and Vitreous

Morphologic anatomy • vitreoretinal interface • acute inflammation

The neurosensory retina is a specialized extension of the central nervous system.

Retinal layer arrangement governs the appearance of hemorrhages and exudates.

The vitreoretinal interface becomes clinically important in aging, vascular injury, and infection.

SCHEMATIC

Vitreous cavity

Neurosensory retina

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

Reconstruct the retinal layers and relate their orientation to fundus findings.

Explain retinal pigment epithelium and vitreous contributions to pathology.

Distinguish infectious retinitis, endophthalmitis, and panophthalmitis by compartment and route.

Apply these principles to retinal detachment and neovascular disease.

SCHEMATIC

Object

Morphology

Mechanism

Application

Slide 3 · The retina is neural tissue

Neurosensory retina and optic nerve originate embryologically from the diencephalon.

The retina therefore shares important biologic responses with the brain.

Retinal injuries are interpreted through both neurobiology and ocular anatomy.

SCHEMATIC

Diencephalon

Neurosensory retina

Response to injury

Slide 4 · A CNS-type injury response: Gliosis

Retinal injury elicits gliosis rather than an ordinary fibrous tissue response.

This response parallels the central nervous system.

Gliosis becomes relevant to the membranes complicating some retinal detachments.

SCHEMATIC

Neurosensory injury

Glial response

Potential retinal membrane

Slide 5 · The retina lacks lymphatics

As in the brain, the neural retina does not have lymphatic vessels.

This feature distinguishes retinal tissue from many other peripheral organs.

Blood-borne dissemination nevertheless provides an infectious route to the retina.

SCHEMATIC

Neural retina

No lymphatics

Hematogenous access possible

Slide 6 · Retina and vitreous occupy adjoining compartments

The vitreous lies immediately inside the neurosensory retinal surface.

The retinal pigment epithelium lies external to the neurosensory retina.

The posterior hyaloid forms a mechanically important interface with retinal inner surface.

SCHEMATIC

Vitreous cavity

Neurosensory retina

Slide 7 · Two retinal components must be distinguished

Neurosensory retina: Stratified neural tissue participating in vision.

Retinal pigment epithelium (RPE): Supporting epithelium facing photoreceptor outer segments.

The potential space between these components is the plane of retinal detachment.

SCHEMATIC

Neurosensory retina

Retinal pigment epithelium

Posterior hyaloid apposed to ILM

Slide 8 · Retinal layers: Orientation from vitreous to choroid

Internal limiting membrane faces the vitreous.

The nerve fiber and ganglion cell layers are relatively internal.

Plexiform and nuclear layers occupy the deeper retina.

Photoreceptors contact the RPE at the outer boundary.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Slide 9 · Internal limiting membrane is a surface landmark

The internal limiting membrane forms the innermost retinal boundary.

The posterior hyaloid may remain apposed to or separate from this surface.

Neovascular tissue crossing this surface is clinically meaningful in proliferative retinopathy.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Slide 10 · The nerve fiber layer is oriented tangentially

Ganglion cell axons run approximately parallel to the retinal inner surface.

Bleeding confined to this layer follows its elongated anatomical architecture.

This produces the characteristic superficial flame-shaped pattern.

SCHEMATIC

Nerve fiber layer

Parallel orientation

Deep retinal axis

Slide 11 · Ganglion cell and inner plexiform layers

The ganglion cell layer lies adjacent to the nerve fiber layer.

The inner plexiform layer sits deeper within the neural retina.

These landmarks help separate superficial from deep retinal pathology.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Slide 12 · The inner nuclear layer is a depth landmark

The inner nuclear layer lies between the two plexiform layers.

Pathologic material deeper than the nerve fiber layer has a different funduscopic appearance.

A three-dimensional lesion may appear rounded in frontal view.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Slide 13 · Outer plexiform layer: Exudate localization

Fluid leaking from retinal vessels can leave exudative material in the outer plexiform layer.

This distribution is especially important around the macula.

Location within the retinal laminae explains a recognizable funduscopic pattern.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Outer plexiform deposits

Slide 14 · Outer nuclear layer and photoreceptor axis

The outer nuclear layer precedes the photoreceptor segments on the route toward the RPE.

Deep retinal elements are predominantly perpendicular to the inner limiting membrane.

This geometric orientation differs from the superficial nerve fiber layer.

SCHEMATIC

Nerve fiber layer

Parallel orientation

Deep retinal axis

Slide 15 · Photoreceptor outer segments face the RPE

Rods and cones sit externally within the neurosensory retina.

The RPE has a vital role in maintaining photoreceptor outer segments.

Disease at this interface can compromise retinal function even without a retinal tear.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Slide 16 · The RPE is derived from the optic vesicle

The RPE and neurosensory retina share developmental origins in the primary optic vesicle.

The optic vesicle is an outpouching of the developing brain.

An embryologic connection explains why both tissues form one functional interface.

SCHEMATIC

Primary optic vesicle

Neurosensory retina + RPE

Photoreceptor interface

Slide 17 · RPE dysfunction links to retinal degeneration

Damage to the RPE–photoreceptor interface is implicated in hereditary retinal degeneration.

Retinitis pigmentosa is an example noted by Robbins.

The distinction is loss of support, not necessarily primary infection or hemorrhage.

SCHEMATIC

RPE–photoreceptor dysfunction

Photoreceptor injury

Visual impairment

Slide 18 · Retinal detachment is a tissue-plane separation

Detachment separates neurosensory retina from the underlying RPE.

It is not synonymous with posterior vitreous detachment.

Fluid or traction can disrupt the normal interface.

SCHEMATIC

RPE

Neurosensory retina

Subretinal fluid without retinal break

Slide 19 · Layer localization governs what the examiner sees

The morphology of a hemorrhage depends on the layer in which blood accumulates.

Superficial and deep hemorrhages can have different shapes in the same eye.

Vessel leakage also produces exudates at characteristic retinal depths.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Slide 20 · Flame hemorrhage: The superficial pattern

Blood within the nerve fiber layer spreads along tangential fibers.

The resulting ophthalmoscopic appearance is elongated or flame-shaped.

Shape indicates depth; It does not by itself establish a single etiology.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Superficial

Slide 21 · Dot hemorrhage: Deep retinal cross-section

The deeper layers are oriented perpendicular to the retinal surface.

An intraretinal column of hemorrhage is seen end-on as a dot.

This accounts for an appearance distinct from nerve fiber layer hemorrhage.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Deeper retina

Slide 22 · Flame and dot hemorrhages compared

Flame: Nerve fiber layer, horizontal orientation, elongated appearance.

Dot: Deeper retinal layers, perpendicular orientation, round appearance.

The same underlying vascular disorder may produce more than one pattern.

Hemorrhage pattern

Retinal plane

Fundus form

Flame

Nerve fiber layer

Streak or flame

Dot

Deeper retinal layers

Rounded dot

Slide 23 · Layer geometry predicts hemorrhage shape

Blood distribution is constrained by the tissue planes surrounding it.

Parallel fibers favor longitudinal spread.

Perpendicular architecture yields rounded cross-sections during ophthalmoscopy.

SCHEMATIC

Nerve fiber layer

Parallel orientation

Deep retinal axis

Slide 24 · Exudates reflect vessel permeability

Leaky retinal vessels release material into retinal tissue.

Exudates characteristically accumulate in the outer plexiform layer.

The pathologic finding is therefore both vascular and laminar.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Outer plexiform deposits

Slide 25 · Macular location matters for exudates

Outer plexiform exudation especially within the macula.

Anatomical localization helps link retinal microangiopathy to visual disturbance.

Recognize the lesion by its distribution before interpreting its cause.

SCHEMATIC

Stylized fundus — not clinical evidence

Slide 26 · Retinal vessel injury: A pattern-based reading

Hemorrhage indicates extravasated blood in a retinal compartment.

Exudate indicates leakage of material from vessels.

Retinal vascular occlusion can produce infarction and secondary structural effects.

Finding

Basic mechanism

Hemorrhage

Blood escapes a vessel

Exudate

Vascular fluid/material leakage

Cotton-wool spot

Nerve fiber layer infarction

Slide 27 · Diabetic microangiopathy: An application

Diabetic retinal vessels develop structural and permeability abnormalities.

Microaneurysms, hemorrhages, and outer plexiform exudates may coexist.

This application illustrates why depth, not disease name alone, predicts morphology.

SCHEMATIC

Stylized fundus — not clinical evidence

Slide 28 · Cotton-wool spot: A different superficial lesion

A cotton-wool spot represents a nerve fiber layer infarct.

It is not simply a yellow outer plexiform exudate.

Both lesions may be present in retinal vascular disease, but indicate different processes.

Lesion

Layer

Process

Cotton-wool spot

Nerve fiber layer

Focal infarction

Hard exudate

Outer plexiform layer

Vascular leakage

Slide 29 · Diabetic neovascularization reaches the surface

Ischemic retinal disease can drive VEGF-associated neovascularization.

Proliferative disease features vessels extending beyond the internal limiting membrane.

Their relationship to posterior vitreous matters for later hemorrhage and traction.

SCHEMATIC

Retinal nonperfusion

VEGF expression

Surface neovascularization

Slide 30 · The adult vitreous is avascular

Normal adult vitreous humor contains no intrinsic blood vessels.

Vitreous hemorrhage therefore requires blood entering from adjacent tissues.

Trauma and retinal neovascularization are two source-supported causes.

SCHEMATIC

Vitreous cavity

Neurosensory retina

Slide 31 · Developmental fetal vessels normally regress

Vessels running through fetal vitreous are normally lost during development.

Incomplete regression can leave persistent fetal vascular tissue.

The resulting lesion may present as a retrolental mass.

SCHEMATIC

Fetal vitreous vasculature

Incomplete regression

Persistent fetal vasculature

Slide 32 · Persistent fetal vasculature: Anatomical consequence

A retrolental mass can arise when fetal vitreous vasculature persists.

The lesion originates in abnormal persistence of developmental structures.

It is distinct from adult vitreous hemorrhage and aging-related degeneration.

SCHEMATIC

Vitreous cavity

Neurosensory retina

Slide 33 · Vitreous hemorrhage compromises transparency

Hemorrhage may opacify a normally transparent vitreous compartment.

Trauma and pathologic retinal neovascularization are mechanisms.

The mechanism determines why blood enters an avascular gel.

SCHEMATIC

Trauma / neovascular vessels

Vitreous blood

Optical opacity

Slide 34 · Aging vitreous may liquefy and collapse

The vitreous gel can liquefy with aging.

Structural collapse may create the subjective perception of floaters.

Vitreous alteration precedes or accompanies some posterior interface changes.

SCHEMATIC

Vitreous aging

Liquefaction and collapse

Floaters

Slide 35 · Posterior hyaloid is the vitreoretinal boundary

The posterior hyaloid is the posterior face of the vitreous.

It is closely related to the internal limiting membrane of the retina.

Its adhesion and separation are important in traction-mediated pathology.

SCHEMATIC

Neurosensory retina

Retinal pigment epithelium

Posterior hyaloid apposed to ILM

Slide 36 · Posterior vitreous detachment: The event

The posterior hyaloid can separate from the neurosensory retina with aging.

This is a vitreous–retinal surface event.

It differs anatomically from neurosensory retinal detachment from RPE.

SCHEMATIC

Neurosensory retina

Retinal pigment epithelium

Separated posterior hyaloid

Potential focal traction

Slide 37 · Two different detachments must not be confused

Posterior vitreous detachment: Posterior hyaloid leaves retinal surface.

Retinal detachment: Neurosensory retina separates from RPE.

The former can exert traction contributing to the latter.

Event

Separated structures

Posterior vitreous detachment

Hyaloid from retinal surface

Retinal detachment

Neurosensory retina from RPE

Slide 38 · Focal vitreoretinal adhesion can produce traction

During hyaloid separation, sites of strong adhesion may remain.

The separating posterior vitreous can pull on the retina at these sites.

A sufficiently strong mechanical stress may cause a retinal tear.

SCHEMATIC

Neurosensory retina

Retinal pigment epithelium

Separated posterior hyaloid

Potential focal traction

Slide 39 · Retinal tear provides a route for vitreous fluid

A full-thickness defect opens access beneath the neurosensory retina.

Liquefied vitreous can pass through the tear.

Subretinal fluid separates retina from RPE in rhegmatogenous detachment.

SCHEMATIC

RPE

Neurosensory retina

Retinal break → fluid entry

Slide 40 · Nonrhegmatogenous detachment has no tear

Retinal separation also occurs without any full-thickness retinal break.

Fluid can accumulate beneath retina with vascular exudation or RPE dysfunction.

Examples include severe hypertension and choroidal tumors.

SCHEMATIC

RPE

Neurosensory retina

Subretinal fluid without retinal break

Slide 41 · Neovascular membranes can couple retina and vitreous

In proliferative retinopathy, fragile surface vessels may be accompanied by fibroglial tissue.

The posterior hyaloid can exert force on this neovascular interface.

Traction can precipitate vitreous hemorrhage.

SCHEMATIC

Surface neovascular membrane

Posterior vitreous traction

Vitreous hemorrhage

Slide 42 · Vitreoretinal interface: Three separate failures

Mechanical: Focal adhesion transmits traction to retina.

Vascular: Fragile new vessels bleed into vitreous.

Barrier: Retinal/RPE fluid imbalance creates subretinal collections.

Failure

Primary result

Traction

Tear / retinal distortion

Fragile new vessels

Vitreous hemorrhage

Subretinal fluid

Nonrhegmatogenous detachment

Slide 43 · Infectious retinitis begins within retinal tissue

A range of pathogens can produce infectious retinitis.

The retina may be reached by organisms carried in blood.

Retinitis is not identical to purulent inflammation filling the vitreous.

SCHEMATIC

Vitreous cavity

Neurosensory retina

Inflammatory exudatewithin vitreous

Slide 44 · Bloodstream dissemination to the retina

A hematogenous route allows systemic infection to seed retinal tissue.

Candida is one example.

Disseminated disease can yield multiple retinal abscesses.

SCHEMATIC

Systemic infection

Hematogenous spread

Retinal seeding

Abscesses

Slide 45 · Candida retinitis: Source-supported settings

Disseminated Candida infection may seed the retina.

Intravenous drug use and other causes of candidemia.

Systemic infection supplies the route; Retinal abscesses are a possible tissue consequence.

SCHEMATIC

Candidemia

Retinal hematogenous seeding

Retinal abscesses

Slide 46 · Multiple retinal abscesses imply blood-borne spread

Hematogenous spread typically produces multiple retinal abscesses.

Multiplicity is linked here to dissemination rather than a single local wound.

Determine whether the infection remains retinal or extends into the vitreous.

SCHEMATIC

Blood-borne organisms

Multiple retinal foci

Potential intraocular spread

Slide 47 · Cytomegalovirus retinitis: Host context

CMV retinitis is a major source of visual morbidity in immunocompromised individuals.

The textbook especially emphasizes patients with AIDS.

Host immune status changes the infectious differential.

SCHEMATIC

Immunocompromise

CMV retinitis

Visual morbidity

Slide 48 · The retina and vitreous are different infection sites

Retinitis refers to inflammation within retinal tissue.

Endophthalmitis denotes substantial inflammation involving intraocular compartments, notably the vitreous.

The tissue compartment predicts the consequence for delicate retinal cells.

Condition

Main compartment

Retinitis

Retinal tissue

Endophthalmitis

Interior of globe / vitreous

Slide 49 · Endophthalmitis: An intraocular suppurative process

Exogenous from endogenous entry routes.

The retina lines the vitreous cavity and poorly tolerates purulent vitreous inflammation.

Irreversible retinal injury may develop over only a few hours.

SCHEMATIC

Vitreous cavity

Neurosensory retina

Inflammatory exudatewithin vitreous

Slide 50 · Exogenous endophthalmitis: Direct entry

Organisms originate in the external environment.

They access the eye through a wound in the ocular wall.

Examples include postoperative complications and penetrating ocular injury.

SCHEMATIC

Ocular surgery / penetrating injury

External inoculation

Endophthalmitis

Slide 51 · Endogenous endophthalmitis: Hematogenous entry

Organisms reach the eye through bloodstream dissemination.

The initial source is outside the eye.

Robbins gives pulmonary infection as an example of a distant source.

SCHEMATIC

Extraocular infection

Bloodstream

Endogenous endophthalmitis

Slide 52 · Exogenous versus endogenous routes

The designation describes how the organism reaches the eye.

Exogenous: External access through an ocular wound.

Endogenous: Bloodstream transport from systemic infection.

Feature

Exogenous

Endogenous

Entry route

Through ocular wound

Through bloodstream

Typical setting

Surgery / penetration

Systemic infection

Primary source

Outside environment

Extraocular infection

Slide 53 · Suppurative vitreous inflammation rapidly injures retina

Retinal tissue borders the vitreous cavity directly.

Purulent inflammation of the vitreous is especially poorly tolerated.

Robbins cautions that a few hours can be enough for permanent retinal damage.

SCHEMATIC

Vitreous cavity

Neurosensory retina

Inflammatory exudatewithin vitreous

Slide 54 · Why endophthalmitis is time-critical

Anatomy: Retina lines the inflamed vitreous cavity.

Cellular vulnerability: Neural retina has limited tolerance for destructive inflammation.

Clinical implication: Suspected endophthalmitis warrants immediate specialist assessment.

SCHEMATIC

Vitreous suppuration

Retinal exposure

Irreversible damage possible

Slide 55 · Panophthalmitis extends across ocular coats

The process affects retina, choroid, and sclera.

Inflammation extends beyond the globe into the orbit.

It therefore denotes a more anatomically extensive process than isolated retinitis.

SCHEMATIC

Vitreous cavity

Neurosensory retina

Scleral + orbital extension

Slide 56 · Intraocular-to-orbital extension: The concept

Retinitis is anatomically limited to retina.

Endophthalmitis involves internal ocular compartments.

Panophthalmitis denotes destructive extension through ocular coats into orbit.

SCHEMATIC

Retinal infection

Intraocular suppuration

Full-thickness / orbital extension

Slide 57 · Three inflammatory diagnoses by extent

Retinitis is retinal tissue inflammation.

Endophthalmitis is infection/inflammation within the globe, often involving vitreous.

Panophthalmitis spans retina, choroid, sclera, and orbit.

Diagnosis

Anatomical extent

Retinitis

Retina

Endophthalmitis

Interior globe / vitreous

Panophthalmitis

Retina + choroid + sclera + orbit

Slide 58 · Compartment anatomy resolves diagnostic ambiguity

Name the affected tissue first: Retina, vitreous, ocular coats, or orbit.

Then identify the route: Hematogenous versus direct inoculation.

Finally assess severity and risk of irreversible retinal injury.

SCHEMATIC

Localization

Entry route

Retinal risk

Slide 59 · Case: Multifocal retinal inflammation

A patient has bloodstream Candida infection and multiple separate retinal inflammatory foci.

The ocular surface has no reported penetrating wound.

What mechanism most directly explains the retinal distribution?

SCHEMATIC

Systemic candidemia

?

Multiple retinal lesions

Slide 60 · Case analysis: Candida retinitis

Most consistent mechanism: Hematogenous retinal seeding.

Dissemination can create multiple retinal abscesses.

Further clinical evaluation must assess spread beyond retina into vitreous.

SCHEMATIC

Candidemia

Bloodstream retinal seeding

Multiple abscesses

Slide 61 · Case: Rapid intraocular inflammation after surgery

A patient develops a severe intraocular inflammatory syndrome after ocular surgery.

The suspected organism entered through the surgical wound.

Which route-based term best categorizes the process?

SCHEMATIC

Ocular surgery

Wound entry

?

Slide 62 · Case analysis: Exogenous endophthalmitis

The organism arrives from the environment through a surgical opening.

This is the exogenous route.

Vitreous suppuration threatens irreversible retinal injury and is time-critical.

SCHEMATIC

Wound inoculation

Exogenous endophthalmitis

Retinal risk

Slide 63 · Case: An aging vitreoretinal interface

An older individual notes new floaters during vitreous structural change.

Posterior hyaloid separation is detected.

What nearby anatomical event must remain conceptually distinct?

SCHEMATIC

Neurosensory retina

Retinal pigment epithelium

Separated posterior hyaloid

Potential focal traction

Slide 64 · Case analysis: Vitreous versus retinal detachment

Posterior vitreous detachment is hyaloid separation from retinal surface.

Retinal detachment is neurosensory separation from RPE.

Focal hyaloid traction can contribute to a retinal tear, linking the two events.

Event

Separation plane

PVD

Hyaloid–retinal surface

Retinal detachment

Neurosensory retina–RPE

Slide 65 · Integrating the pathology: Structure → pattern

Retinal layers explain superficial versus deep hemorrhage shape.

RPE and photoreceptor contact explains vulnerability at the outer interface.

Posterior hyaloid mechanics explain traction and hemorrhage.

Vitreous proximity explains urgency of suppurative infection.

SCHEMATIC

Layer / interface anatomy

Injury mechanism

Observed clinical pattern

Slide 66 · Core concepts for clinicopathologic practice

Identify the retinal layer before interpreting lesion shape.

Distinguish hyaloid separation from neurosensory retinal detachment.

Use the route of entry to classify endophthalmitis.

Recognize that purulent vitreous inflammation can rapidly destroy neural retina.

SCHEMATIC

Vitreous / internal limiting membrane

Nerve fiber layer

Ganglion cell layer

Inner plexiform layer

Inner nuclear layer

Outer plexiform layer

Outer nuclear layer

External limiting membrane

Rods and cones

Retinal pigment epithelium

Slide 67 · Selected references

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th edition. Elsevier; 2026.

Textbook sections: Retina and Vitreous; Retinal Detachment; Diabetes Mellitus (retinal pathology).