BCSC Section 12: Retina and Vitreous Lecture Notes

Flashcards covering key concepts from the BCSC Section 12 lecture on Retina and Vitreous, including basic anatomy, diagnostic approaches, and diseases related to retinal health.

What is the main purpose of the Basic and Clinical Science Course (BCSC)?

To provide a comprehensive curriculum for ophthalmology residents and practitioners.

Who chairs the BCSC Section 12 for Retina and Vitreous?

Stephen J. Kim, MD.

What type of continuing medical education credit is provided by the American Academy of Ophthalmology?

AMA PRA Category 1 Credits™.

By when must AMA PRA Category 1 Credits™ be claimed by the participants?

By June 1, 2025.

What major outcomes did the Age-Related Eye Disease Study (AREDS) reveal?

Vitamin and zinc supplementation reduces the risk of progression to advanced stages of AMD.

What is the difference between nonneovascular AMD and neovascular AMD?

Nonneovascular AMD includes geographic atrophy, while neovascular AMD is characterized by the presence of macular neovascularization (MNV).

What are the risk factors associated with Age-Related Macular Degeneration (AMD)?

Age, family history, smoking, and light iris color.

What is the role of the retinal pigment epithelium (RPE) in the retina?

It absorbs light, phagocytoses outer segments of photoreceptors, and forms the outer blood–ocular barrier.

What is hypopigmentation in the context of AMD?

Decreased pigmentation of the retinal pigment epithelium associated with advanced AMD.

How is diabetic retinopathy classified?

Into nonproliferative and proliferative stages.

What are some examples of imaging technologies used in retinal examinations?

Fundus photography, Optical Coherence Tomography (OCT), and Fluorescein Angiography.

What are drusen and their significance in AMD?

Drusen are abnormal deposits under the RPE and associated with an increased risk of progression to late AMD.

What is the primary treatment modality for neovascular AMD?

Anti-vascular endothelial growth factor (anti-VEGF) agents.

What is the significance of the Arden index in electro-oculography?

It measures the ratio of the amplitude of the light peak to the dark trough, indicating RPE health.

What does Optical Coherence Tomography Angiography (OCTA) visualize?

Retinal vasculature and blood flow at high resolution without needing contrast agents.

How can patients use the Amsler grid for self-monitoring?

To detect visual distortion due to AMD, allowing for early intervention.

What is the primary focus of Chapter 1 in the BCSC Section 12?

Basic Anatomy of the retina and vitreous.

What types of tests assess color vision?

Ishihara plates and Farnsworth-Munsell D-15 test.

What is the definition of geographic atrophy in AMD?

Focal atrophy of the retina with absent RPE, often leading to vision loss.

What does multifocal electroretinography assess?

Cone system function in a topographic manner across the central visual field.

What are the primary components of the vitreous humor?

The vitreous is composed of approximately 98\% - 99\% water, with a structural framework consisting of collagen fibers (predominantly Type II) and hyaluronic acid.

Distinguish between the inner and outer blood-retinal barrier (BRB).

The inner BRB is formed by tight junctions between retinal capillary endothelial cells, whereas the outer BRB is formed by tight junctions (zonula occludentes) between cells of the retinal pigment epithelium (RPE).

What modification was made in the AREDS2 formulation regarding beta-carotene?

AREDS2 replaced beta-carotene with lutein (10 mg) and zeaxanthin (2 mg) to eliminate the increased risk of lung cancer found in smokers taking beta-carotene.

How are 'cotton-wool spots' defined in retinal imaging?

They are white, fluffy-looking lesions in the retina that represent microinfarctions of the retinal nerve fiber layer (RNFL) due to axoplasmic flow stasis.

What characterizes Proliferative Diabetic Retinopathy (PDR) upon clinical examination?

The hallmark is the presence of neovascularization, specifically neovascularization of the disc (NVD) or neovascularization elsewhere (NVE), often associated with vitreous or preretinal hemorrhage.

What is the significance of the 'dark choroid' sign in Fluorescein Angiography (FA)?

It is a characteristic finding in Stargardt disease, where accumulated lipofuscin in the RPE blocks the underlying choroidal fluorescence.

Name the layers of the neurosensory retina from internal to external.

1. Internal limiting membrane
2. Nerve fiber layer
3. Ganglion cell layer
4. Inner plexiform layer
5. Inner nuclear layer
6. Outer plexiform layer
7. Outer nuclear layer
8. External limiting membrane
9. Photoreceptor layer (Inner and Outer segments)

What is the primary mechanism of action for Anti-VEGF therapy in neovascular AMD?

These agents bind to Vascular Endothelial Growth Factor (VEGF) molecules, inhibiting their interaction with receptors to reduce vascular permeability and suppress abnormal blood vessel growth.

What are the three primary types of retinal detachment?

1. Rhegmatogenous (caused by a retinal break)
2. Tractional (caused by membranes pulling the retina)
3. Exudative (caused by fluid accumulation beneath the retina without a break)

What is the clinical significance of a 'cherry-red spot' in retinal examination?

It is a hallmark sign of a central retinal artery occlusion (CRAO), where the pale, edematous retina contrasts with the normal reddish color of the choroid visible through the thin fovea.

What is the role of Mueller cells within the neurosensory retina?

They are the principal glial cells of the retina, extending from the internal limiting membrane to the external limiting membrane, providing structural support and maintaining metabolic homeostasis.

Define the Foveal Avascular Zone (FAZ).

A region in the center of the fovea that is devoid of retinal capillaries, usually measuring approximately 500 \mu m in diameter, visualized clearly on fluorescein angiography or OCTA.

What characterizes Central Serous Chorioretinopathy (CSCR)?

An idiopathic condition characterized by a localized serous detachment of the neurosensory retina, often associated with one or more leaks at the level of the retinal pigment epithelium (RPE).

How are 'hard exudates' distinguished from 'cotton-wool spots' clinically?

Hard exudates are yellow, waxy-colored deposits with sharp margins composed of lipids, whereas cotton-wool spots are white, fluffy lesions representing microinfarctions of the retinal nerve fiber layer (RNFL).

What is the pathophysiology of a macular hole?

It typically results from anteroposterior and tangential vitreoretinal traction at the fovea, leading to a full-thickness defect in the neurosensory retina.

What are the four anatomical sub-zones of the macula?

The foveola, fovea, parafovea, and perifovea.

Where is the highest density of cones located in the retina?

In the foveola (approximately 0.35 mm in diameter), which is entirely devoid of rods.

Name the locations of the strongest vitreous attachments in descending order of strength.

1. Vitreous base
2. Optic disc margin
3. Fovea
4. Along major retinal vessels

In a standard electroretinogram (ERG), what does the a-wave represent?

It is the initial negative deflection arising from the photoreceptors (rods and cones).

Discuss the dual blood supply of the retina.

The inner retinal layers are supplied by the central retinal artery, while the outer layers (including the RPE and photoreceptors) are nourished by the choriocapillaris via the choroid.

What is a cilioretinal artery and its significance in CRAO?

An anatomical variant found in approximately 15\% - 30\% of individuals; it derives from the ciliary circulation and can spare the fovea/central vision during a central retinal artery occlusion (CRAO).

Define the 'vitreous base'.

A three-dimensional zone extending 1.5 to 2.0 mm anterior to the ora serrata and 1.0 to 3.0 mm posterior to it, where the vitreous is most strongly adherent.

What are hyalocytes?

They are mononuclear cells, thought to be resident macrophages, located in the vitreous cortex that are responsible for collagen and hyaluronan synthesis and phagocytosis.

What is Cloquet's canal?

A remnant of the primary vitreous extending from the optic disc to the posterior lens capsule, representing the former path of the hyaloid artery.

In a standard electroretinogram (ERG), what does the b-wave represent?

A positive deflection following the a-wave, generated primarily by post-synaptic activity in the inner retina, specifically bipolar and Mueller cells.

Name the consecutive phases of a normal fluorescein angiogram (FA).

1. Choroidal (pre-arterial) phase
2. Arterial phase
3. Arteriovenous (capillary) phase
4. Venous phase
5. Late (recirculation/staining) phase

What is the classic clinical triad of Retinitis Pigmentosa (RP)?

1. Bone-spicule pigmentation in the peripheral retina
2. Arteriolar attenuation
3. Waxy pallor of the optic disc

What are the characteristic clinical findings of a Central Retinal Vein Occlusion (CRVO)?

Diffuse intraretinal hemorrhages in all four quadrants (often described as a 'blood and thunder' appearance), dilated and tortuous veins, optic disc edema, and macular edema.

What is the primary objective of Panretinal Photocoagulation (PRP) in proliferative diabetic retinopathy (PDR)?

To reduce the oxygen demand of the peripheral retina and the production of vascular endothelial growth factor (VEGF), promoting the regression of neovascularization.

Define the 'ora serrata'.

The peripheral termination of the retina where the neurosensory layers transition into the non-pigmented ciliary epithelium.

What cell types have their nuclei located within the Inner Nuclear Layer (INL)?

The INL contains the nuclei of bipolar, horizontal, and amacrine cells, as well as the nuclei of Mueller (glial) cells.

What is the primary advantage of Indocyanine Green Angiography (ICGA) compared to Fluorescein Angiography (FA)?

ICGA utilizes a near-infrared wavelength that better penetrates the retinal pigment epithelium (RPE), macular pigment, and thin layers of blood or lipid, allowing for superior visualization of the choroidal vasculature.

How is the characteristic leakage of Cystoid Macular Edema (CME) described on late-phase fluorescein angiography?

It is described as a 'petaloid' pattern, resulting from the accumulation of dye in the cystic spaces of Henle's fiber layer in the macula.

What is the composition of the opacities found in Asteroid Hyalosis?

They are composed of calcium-phospholipid complexes suspended within the vitreous gel.

Define Terson syndrome.

The occurrence of intraocular hemorrhage (vitreous, subhyaloid, or intraretinal) in association with subarachnoid or intracranial hemorrhage, often related to a sudden increase in intracranial pressure.

What are the characteristic findings of a Macular Epiretinal Membrane (ERM) on Optical Coherence Tomography (OCT)?

A hyperreflective line on the inner surface of the retina, often associated with undulation of the retinal layers, retinal thickening, and loss of the foveal contour.

What characterizes the 'pavingstone degeneration' (peripheral chorioretinal atrophy)?

Distinct, small, yellow-white areas of chorioretinal atrophy in the peripheral retina, often showing prominent underlying choroidal vessels and representing focal loss of the RPE and outer retinal layers.

In the context of retinal detachment, what is 'Shafer’s sign'?

The presence of pigment cells (often referred to as 'tobacco dust') in the anterior vitreous, which is highly suggestive of a retinal tear or rhegmatogenous retinal detachment.

What is the primary finding in 'Commotio Retinae'?

A transient opacification of the outer retina (referred to as 'Berlin’s edema' when involving the macula) caused by traumatic disruption of

What is the primary finding in Commotio Retinae?

A transient opacification of the outer retina (referred to as Berlin’s edema when involving the macula) caused by traumatic disruption of the photoreceptor outer segments and the RPE.

Define Synchysis Scintillans.

A condition where cholesterol crystals form and float within the vitreous gel, typically occurring after trauma or hemorrhage; these crystals are highly mobile and settle inferiorly due to gravity, distinguishing them from asteroid hyalosis.

What is the Watzke-Allen test?

A clinical test used to confirm a full-thickness macular hole; a narrow vertical slit lamp beam is projected over the fovea, and the patient's report of a break or narrowing in the light is considered a positive result.

Identify the characteristic findings of Sickle Cell Retinopathy.

It typically presents with:
1. Peripheral arteriolar occlusions
2. Arteriovenous anastomoses ('hairpin loops')
3. 'Sea-fan' neovascularization (Stage
3)
4. Vitreous hemorrhage or tractional retinal detachment (Stages
4-5)

Compare Lattice Degeneration and Pavingstone Degeneration.

• Lattice Degeneration: Peripheral retinal thinning with overlying vitreous liquefaction and strong marginal adhesion; associated with an increased risk of retinal tears.
• Pavingstone Degeneration: (Peripheral chorioretinal atrophy) A benign, focal loss of the RPE and outer retinal layers, often allowing visualization of the underlying large choroidal vessels.

What is Purtscher Retinopathy?

An occlusive microangiopathy presenting with bilateral peripapillary cotton-wool spots and Purtscher-flecken (large areas of retinal whitening), commonly associated with severe head or chest trauma, acute pancreatitis, or systemic vasculitis.

Define White-without-Pressure (WWP).

A peripheral retinal finding characterized by a geographic area of retinal whitening or opacification observed under normal illumination without the need for scleral indentation.

Explain Vitreomacular Traction (VMT) syndrome.

A condition resulting from an incomplete posterior vitreous detachment (PVD) where the vitreous remains attached to the macula, causing mechanical traction that results in retinal thickening, distortion, or the formation of pseudocysts.

What characterizes Polypoidal Choroidal Vasculopathy (PCV)?

A variant of neovascular AMD characterized by an inner choroidal branching vascular network and aneurysmal (polypodal) terminal dilatations, often leading to recurrent serosanguineous pigment epithelial detachments (PEDs).

What is the clinical hallmark of Birdshot Chorioretinopathy?

A bilateral, chronic posterior uveitis strongly associated with the HLA-A29 allele, characterized by multiple cream-colored, oval chorioretinal lesions typically originating near the optic nerve and radiating toward the periphery.