Anatomy of the Sclera and Episclera
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Questions and Answers

Which of the following layers of the sclera is most affected in high myopia?

  • Scleral Stroma
  • Episclera
  • Ciliary Muscles
  • Lamina Fusca (correct)

    • What type of collagen is the primary component of the sclera?

  • Type I (correct)
  • Type III
  • Type IV
  • Type II

    • Which of the following statements about sclera development is TRUE?

  • The sclera develops entirely from mesoderm.
  • The sclera develops from the neural crest and mesoderm. (correct)
  • Development of the sclera is not completed until the seventh month of gestation.
  • The sclera is fully developed at birth.

    • What is the role of scleral spur in the eye?

    <p>Site of attachment for the ciliary muscles. (A)</p> Signup and view all the answers

    What is the primary source of blood supply to the episclera?

    <p>Anterior ciliary arteries (D)</p> Signup and view all the answers

    Which of these layers of the sclera is the most vascular?

    <p>Episclera (B)</p> Signup and view all the answers

    Which type of collagen is NOT found in the sclera?

    <p>Type VII (C)</p> Signup and view all the answers

    Which of the following statements is TRUE about the development of the sclera?

    <p>The sclera is fully developed by the fifth month of gestation. (A)</p> Signup and view all the answers

    What is the function of the longitudinal muscles of the ciliary body?

    <p>To control the shape of the lens. (D)</p> Signup and view all the answers

    Which of the following is NOT a layer of the sclera?

    <p>Conjunctiva (D)</p> Signup and view all the answers

    What is a common cause of episcleritis?

    <p>All of the above (D)</p> Signup and view all the answers

    Which of the following is NOT a characteristic symptom of episcleritis?

    <p>Severe, constant pain (A)</p> Signup and view all the answers

    What is the primary difference between episcleritis and scleritis in terms of their appearance?

    <p>Episcleritis involves a 'bowing' of the optic section, while scleritis is more dome-shaped. (C)</p> Signup and view all the answers

    What two types of episcleritis are most commonly observed?

    <p>Diffuse and nodular (C)</p> Signup and view all the answers

    Which of the following is a systemic non-infectious cause of episcleritis?

    <p>Psoriatic arthritis (B)</p> Signup and view all the answers

    Which of the following correctly describes the relationship between episcleritis and conjunctivitis?

    <p>Episcleritis is a deeper inflammation than conjunctivitis. (B)</p> Signup and view all the answers

    Which of the following is a characteristic feature of diffuse episcleritis?

    <p>Engorgement of episcleral vessels in a radial direction (C)</p> Signup and view all the answers

    What is the most common systemic cause of episcleritis?

    <p>Rheumatoid arthritis (RA) (B)</p> Signup and view all the answers

    In which scenario is a cotton tip applicator helpful in differentiating between episcleritis and scleritis?

    <p>When assessing the depth of the inflammation. (C)</p> Signup and view all the answers

    Which of these is NOT a common finding in episcleritis?

    <p>Severe pain with muscle movement (B)</p> Signup and view all the answers

    Which of the following is NOT a common complication of posterior scleritis?

    <p>Macular Degeneration (C)</p> Signup and view all the answers

    In the context of anterior scleritis, what is the significance of a positive phenylephrine test?

    <p>It is a sign of episcleritis (C)</p> Signup and view all the answers

    When examining a patient with scleritis, the clinician notes a deep bluish, violaceous hue in the affected eye. What is the likely cause of this color change?

    <p>Exposure of the uvea due to scleral thinning (C)</p> Signup and view all the answers

    Which of the following is a common systemic association with scleritis?

    <p>Rheumatoid Arthritis (B)</p> Signup and view all the answers

    A patient presents with severe, excruciating pain in their eye that radiates to the forehead, brow, and jaw. Which of the following diagnostic tests would be most useful in differentiating between episcleritis and anterior scleritis?

    <p>Slit-lamp exam with phenylephrine (D)</p> Signup and view all the answers

    A patient with scleritis is found to have a high ESR. What does this finding suggest?

    <p>Systemic inflammation (A)</p> Signup and view all the answers

    Which of the following is a common presenting symptom of episcleritis?

    <p>Mild discomfort (A)</p> Signup and view all the answers

    What is the characteristic feature that differentiates Scleromalacia Perforans from other forms of scleritis?

    <p>The absence of inflammation (D)</p> Signup and view all the answers

    Which of the following is NOT a recognized treatment option for Scleromalacia Perforans?

    <p>Antiviral medications (B)</p> Signup and view all the answers

    In the context of Scleromalacia Perforans, what type of immune response is believed to be responsible for vessel damage?

    <p>Type III hypersensitivity (C)</p> Signup and view all the answers

    Flashcards

    Sclera

    The white outer layer of the eyeball, composed of three layers and provides structure.

    Episclera

    The most external layer of the sclera, it is vascular and supplies blood from anterior ciliary arteries.

    Scleral Stroma

    The middle layer of the sclera, primarily made up of type I collagen providing strength.

    Lamina Fusca

    The deepest layer of the sclera, affected in high myopes, connecting to the choroid.

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    Type I Collagen

    The primary type of collagen found in the sclera, providing tensile strength.

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    Mesoderm

    The embryonic layer from which the sclera develops during gestation.

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    Neural Crest

    Embryonic cells contributing to the formation of various structures including the sclera.

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    Scleral Spur

    A circular band of tissue providing attachment for the ciliary body muscles.

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    Ciliary Musculature

    Muscles attached at the scleral spur that help with lens adjustment.

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    Anterior Ciliary Arteries

    Blood supply to the episclera, supporting the sclera's health.

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    Trabecular meshwork

    A structure that protects the globe's contents and serves as the attachment site for Eye Muscles (EOM).

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    Episcleritis

    Benign inflammation of the episclera, often causing redness and mild pain, with about 60-70% being idiopathic.

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    Superficial episcleral plexus

    A vascular structure located in the episclera, involved in inflammation signs related to episcleritis.

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    Signs of episcleritis

    Symptoms include redness, mild pain on eye movement, and no discharge. Can be sectorial or diffuse.

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    Nodular episcleritis

    A type of episcleritis forming a visible 'nodule' resulting from localized inflammation.

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    Scleritis

    Serious inflammation of the sclera, resulting in congestion of both superficial and deep episcleral plexus with more severe symptoms than episcleritis.

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    Episcleritis vs. Scleritis

    Episcleritis has superficial symptoms with local redness; scleritis shows deeper symptoms and can impact vision emergencies.

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    Common causes of episcleritis

    Can include systemic disorders like RA or SLE, but also idiopathic or traumatic causes.

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    Symptoms of diffuse episcleritis

    Includes diffuse redness, edema, and tenderness; most cases are acute with potential bilateral involvement.

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    Phenylephrine test

    A diagnostic test used to differentiate episcleritis (blanching) from scleritis (no blanching) after applying phenylephrine drops.

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    Scleral edema

    Swelling of the sclera often associated with scleritis, observable with a narrow-slit lamp beam.

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    Nodule mobility test

    A physical examination to check if a nodule in the eye moves with a cotton tip applicator, indicating episcleritis if it does move.

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    Scleromalacia perforans

    A rare condition of progressive thinning of the sclera without inflammation, leading to potential perforation.

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    Anterior uveitis symptoms

    Signs include cells and flare in the anterior chamber, possible photophobia, and associated pain.

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    Treatment for moderate scleritis

    Typically involves mild steroids, NSAIDs, and potentially immunosuppressants if severe or unresponsive.

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    Blue sclera

    A condition where scleral thinning reveals underlying uveal pigment, associated with several connective tissue disorders.

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    Chemical injury to the sclera

    Damage to the sclera caused by exposure to chemicals, which can cause significant harm depending on the substance and duration of contact.

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    Study Notes

    Sclera

    • The sclera is composed of three layers: episclera (vascular layer), scleral stroma, and lamina fusca (posterior layer).
    • Development begins in the fifth month of gestation, originating from neural crest and mesoderm.
    • Primarily composed of type I collagen, with additional types like III, IV, V, VI, and VIII.
    • Scleral spur, a part of the scleral structure, is the site where ciliary musculature and trabecular meshwork attach.
    • Attaches to extraocular muscles (EOMs).
    • Its function protects the globe's contents.

    Episclera

    • Tortuous vessels, more superficial compared to other layers.
    • Supplied by anterior ciliary arteries.
    • Continuous with conjunctival vessels.

    Episcleral and Scleral Vascular Plexuses

    • Two main episcleral plexuses: superficial and deep.
    • Superficial plexus lies above the scleral stoma.
    • Episcleritis can occur due to irritation, congestion of both plexuses is observed in the condition.
    • Scleritis involves both superficial and deep episcleral plexus congestion.

    Additional Information

    • Episcleritis – a benign inflammation of episcleral tissue, often associated with underlying systemic disorders in some cases. More prevalent in young adults.
    • Scleritis – a more severe inflammation compared to episcleritis. Usually, bilateral or sectorial, with a higher potential for underlying systemic disorders.

    Scleritis (additional info)

    • Symptoms: Acute onset of redness and mild pain.
    • Pain typically experienced during eye movement (not muscle movement), anterior segment pain, with one or both eyes.
    • Recurring episodes are common, with no discharge usually and tearing in some cases.
    • Classification: diffuse (80%) widespread redness and edema, and nodular (20%), nodule formation visible to the eye.

    Common Causes of Scleritis (additional info)

    • Systemic conditions (connective tissue diseases like rheumatoid arthritis, systemic lupus erythematosus, and ankylosing spondylitis, inflammatory bowel disease).
    • Infections (bacterial, viral, and fungal).
    • Medications (such as topiramate, used for migraines and seizures, and pamidronate).
    • Trauma or injuries to the eye.
    • Other underlying diseases.

    Differential Diagnosis of Scleritis

    • Scleritis can be misdiagnosed if not examined thoroughly.

    • Other conditions with similar symptoms include iritis, conjunctivitis, and other inflammatory conditions of the eye or face.

    • Differentiating scleral inflammatory diseases from other eye conditions including acute onset of redness can require appropriate diagnostic workup.

    Anterior Scleritis

    • Typically unilateral at onset, but with a higher likelihood of bilateral involvement.
    • Pain: Often severe and perceived as radiating to forehead, brow, jaw or sinuses (CN V division). Patients commonly describe that the pain is worsened with palpation. Pain usually relieved with analgesics.

    Posterior Scleritis

    • A less common form of scleritis, often having a different pattern of inflammation compared to anterior scleritis and an usually more severe course than anterior.

    Necrotizing Scleritis

    • Severe, aggressive form of scleritis characterized by necrotic slough formation without significant surrounding inflammation.
    • Typically associated with severe inflammatory conditions (e.g., rheumatoid arthritis).

    Scleromalacia Perforans

    • Rare type of severe scleral disorder characterized by progressive scleral thinning and necrosis, without inflammation.
    • Often preceded by other inflammatory conditions like rheumatoid arthritis.

    Scleral Inflammation (general information)

    • Pathogenesis of scleral inflammation typically involves immune-mediated or hypersensitivity reactions that damage scleral vasculature.
    • Can be triggered by underlying systemic conditions.
    • The sclera may undergo thinning and vascular changes during severe cases.
    • Can involve the underlying uveal layer and the posterior sclera.

    Scleral Trauma

    • Blunt trauma, high velocity, and penetrating foreign bodies can cause scleral injury.
    • Management involves managing the damage to the sclera, and repairing any associated injuries to the eye.
    • Chemical injury to the sclera can involve either solid matter or liquids that lead to a tissue damage.

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    Episclera & Sclera PDF

    Description

    Explore the intricate structure and function of the sclera and episclera in this informative quiz. Learn about the layers, vascular supply, and related conditions such as episcleritis and scleritis. Test your knowledge on this vital part of the eye anatomy.

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