Microbial Keratitis Overview
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Questions and Answers

Which gland is responsible for producing the lipid layer of the tear film?

  • Lacrimal glands
  • Accessory glands
  • Mucin glands
  • Meibomian glands (correct)

The aqueous layer of the tear film is produced by which of the following?

  • Meibomian glands only
  • Main lacrimal glands only
  • Mucin glands and meibomian glands
  • Main and accessory lacrimal glands (correct)

What is the primary source of the hydrophillic mucin layer of the tear film?

  • Meibomiam glands
  • The mucin layer itself (correct)
  • Accessory glands
  • The aqueous layer

What is the consequence of an abnormality in any of the tear film layers?

<p>Unstable tear film and symptoms of KCS (A)</p> Signup and view all the answers

Which of the following is listed as a type of dry eye disease?

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

Which factor is least likely to contribute to the development of bacterial keratitis?

<p>Excellent contact lens hygiene (B)</p> Signup and view all the answers

A patient presents with a stromal corneal ulcer, profuse tearing, and marked photophobia. What is the most likely stage of disease progression based on these signs and symptoms?

<p>Intermediate, indicating a need for urgent referral. (C)</p> Signup and view all the answers

Which of the following is typically classified as a sign of bacterial keratitis, rather than a symptom?

<p>Stromal abscess formation (A)</p> Signup and view all the answers

A patient presents with a corneal ulcer and anterior chamber activity and hypopyon. What does this suggest?

<p>The patient’s condition may be progressing towards endophthalmitis (B)</p> Signup and view all the answers

Which of the following is the most appropriate first step in managing a patient suspected of bacterial keratitis?

<p>Refer the patient immediately for specialist evaluation and treatment (C)</p> Signup and view all the answers

What is the importance of sending a contact lens and lens case to the referral appointment, in the case of contact lens associated bacterial keratitis?

<p>To culture the lens and case to aid in identifying the causative pathogen. (D)</p> Signup and view all the answers

Which of the following findings is most likely to be associated with a corneal infiltrate rather than bacterial keratitis?

<p>A small peripheral lesion less than 1mm in size with minimal AC reaction (B)</p> Signup and view all the answers

Besides bacterial keratitis, which other condition should be considered as a differential diagnosis in a patient presenting with a corneal ulcer?

<p>Acanthamoeba keratitis (A)</p> Signup and view all the answers

A patient presents with a corneal epithelial defect that appears dendritic and is a contact lens wearer; what is the most appropriate first action?

<p>Immediately refer the patient the same day for possible Acanthamoeba keratitis. (C)</p> Signup and view all the answers

Which condition requires an emergency, same-day referral?

<p>Herpes simplex stromal keratitis in a child (D)</p> Signup and view all the answers

What is the recommended frequency of Zovirax ophthalmic preparation for acute herpes simplex keratitis?

<p>Five times a day (D)</p> Signup and view all the answers

If a patient with herpes simplex keratitis is using Zovirax, when should you consider an urgent referral if the epithelium has not healed?

<p>After 7 days (C)</p> Signup and view all the answers

Which of the following is the primary infection caused by the varicella-zoster virus (VZV)?

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

In herpes zoster ophthalmicus, which cranial nerve is primarily affected, leading to a characteristic vesicular rash?

<p>The fifth cranial nerve (D)</p> Signup and view all the answers

Which of the following is NOT a common sign or symptom of herpes zoster ophthalmicus?

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

A patient with herpes zoster ophthalmicus has vesicles on their nose; what is the approximate chance of ocular involvement?

<p>75% (B)</p> Signup and view all the answers

Which of the following ocular conditions is associated with herpes zoster ophthalmicus?

<p>Hypertensive uveitis (C)</p> Signup and view all the answers

What is the underlying cause of herpes zoster reactivation?

<p>Decreased cell-mediated immunity (C)</p> Signup and view all the answers

Which of the following is NOT a typical cause of recurrent corneal erosion (RCE)?

<p>Severe allergic reaction causing cell detachment. (B)</p> Signup and view all the answers

Why is daily review recommended for a patient with RCE?

<p>To rule out the possibility of infectious keratitis. (C)</p> Signup and view all the answers

What is the recommended dosage for Diclofenac Sodium 0.1% for RCE?

<p>Four times daily for 1-3 days. (B)</p> Signup and view all the answers

Cyclopentolate 1.0% is used to treat what issue associated with RCE?

<p>To relieve ciliary spasm. (D)</p> Signup and view all the answers

If a topical form of Diclofenac Sodium is not available, what is an alternative?

<p>An oral form of Diclofenac Sodium can be purchased over the counter. (D)</p> Signup and view all the answers

What is the main reason for RCE happening with regards to the corneal cells?

<p>The epithelial cells haven't fully attached to the basement membrane and anterior stroma. (D)</p> Signup and view all the answers

Who is usually administered Cyclopentolate 1.0% for the treatment of RCE?

<p>Children and the elderly, and pregnant individuals as an off-label use. (B)</p> Signup and view all the answers

How often is Cyclopentolate 1.0% typically administered for RCE?

<p>Twice a day. (C)</p> Signup and view all the answers

What is the typical duration of time that Diclofenac Sodium 0.1% is used for RCE treatment?

<p>For a period of 1 to 3 days. (C)</p> Signup and view all the answers

What is the definition of Recurrent Corneal Erosion (RCE)?

<p>A repetitive breakdown of the corneal epithelium. (B)</p> Signup and view all the answers

What symptom is NOT commonly associated with corneal epithelial dystrophy?

<p>Consistent blinking (A)</p> Signup and view all the answers

Which management strategy is recommended for preventing symptoms upon waking at night?

<p>Taping eyelids shut (D)</p> Signup and view all the answers

What duration is advised for using lubricants after the last symptom date?

<p>3 months (A)</p> Signup and view all the answers

What can indicate a more severe case of corneal epithelial dystrophy?

<p>Chloramphenicol 1% (D)</p> Signup and view all the answers

Which sign is NOT typically observed in healed corneal epithelial dystrophy?

<p>Obvious edema (A)</p> Signup and view all the answers

What is not a common reason for diagnosing corneal epithelial dystrophy?

<p>Visual acuity testing (B)</p> Signup and view all the answers

Which of these symptoms could indicate corneal epithelial dystrophy upon waking?

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

Which treatment option is aimed at enhancing lubrication in severe cases?

<p>Cyclopentolate 1% (A)</p> Signup and view all the answers

What symptom is commonly described by patients recurring after eye rubbing?

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

What could be a potential sign observed during an examination of someone with corneal epithelial dystrophy?

<p>Some fluorescein staining (A)</p> Signup and view all the answers

What is an unlikely evaluation method for diagnosing corneal epithelial dystrophy?

<p>Visual field testing (D)</p> Signup and view all the answers

What is the recommended follow-up frequency for patients with corneal epithelial dystrophy?

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

What is a typical symptom described by patients when remaining symptoms persist?

<p>Difficulty opening eyes (D)</p> Signup and view all the answers

Which condition is NOT an inflammatory disorder associated with evaporative dry eye?

<p>Diabetes Mellitus (C)</p> Signup and view all the answers

What is a common symptom of evaporative dry eye?

<p>Burning sensation (A)</p> Signup and view all the answers

What management option is a non-pharmacological approach for treating evaporative dry eye?

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

In cases of severe dry eye associated with Sjorjen's Syndrome, which referral is required?

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

What is the characteristic sign of chronic dacryocystitis?

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

Which of the following is a common cause of epiphora?

<p>Excessive tear production (A)</p> Signup and view all the answers

Which treatment option is indicated for acute dacryocystitis?

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

What would indicate a severe case of keratoconjunctival syndrome (KCS)?

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

What symptom might lead to diagnosing exposure keratopathy instead of evaporative dry eye?

<p>Nocturnal lagophthalmos (A)</p> Signup and view all the answers

Which of the following could exacerbate symptoms of evaporative dry eye?

<p>Air conditioning (C)</p> Signup and view all the answers

Which of the following would NOT be a sign of evaporative dry eye?

<p>Excessive tear meniscus (D)</p> Signup and view all the answers

What surgical intervention might be considered for very severe keratoconjunctival syndrome?

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

Which clinical sign might suggest a secondary infection in a case of dacryocystitis?

<p>Purulent discharge from the punctum (B)</p> Signup and view all the answers

Flashcards

Bacterial Microbial Keratitis (MK)

A rare infection of the cornea that occurs in individuals with weakened immune systems, poor contact lens hygiene, or following corneal surgery, resulting from bacterial invasion.

Progression of Bacterial MK

This infection, if left untreated, can progress to endophthalmitis, a severe eye infection that can cause permanent vision loss.

Corneal Ulcer

The characteristic sign is a corneal ulcer, a deep stromal defect with overlying epithelial loss, which can be central or peripheral.

AC Activity in Bacterial MK

Inflammation of the anterior chamber (AC) is common, with or without hypopyon, a collection of inflammatory cells in the anterior chamber.

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Other Signs of Bacterial MK

This includes signs like corneal edema, stromal abscess formation, Descemet's membrane folds, and potentially corneal degradation, necrosis, and thinning, ultimately leading to scar formation.

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Symptoms of Bacterial MK

Symptoms manifest quickly with moderate to severe pain, rapid progression of the infection, profuse tearing, photophobia, redness, discharge, and reduced vision.

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Management of Bacterial MK

Urgent referral to a hospital eye service (HES) is crucial. Treatment includes corneal scraping and cultures to identify the pathogen, and appropriate antibiotic therapy.

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Differentiating Bacterial MK

Differentiating Bacterial MK from other corneal inflammatory conditions like corneal infiltrates and Acanthamoeba Keratitis is essential for proper treatment.

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Recurrent Corneal Erosion (RCE)

A recurring issue where the outer layer of the cornea (epithelium) repeatedly breaks down.

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Mechanical Trauma

A common cause of RCE, often due to a scratch or abrasion on the cornea, usually from something like a fingernail.

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Poor Epithelial Adhesion

Cells on the outer surface of the cornea don't attach properly to the underlying layers, leading to RCE.

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Cyclopentolate (1.0%)

A medication used to relieve ciliary muscle spasms, often prescribed for RCE.

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NSAIDS (Nonsteroidal Anti-inflammatory Drugs)

A class of medications that can reduce pain and inflammation, often used for RCE.

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Diclofenac Sodium (0.1%)

A specific NSAID often used in a topical form for RCE.

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Daily Review

Frequent eye checks are recommended to rule out infections and monitor healing.

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Infectious Keratitis

Inflammation of the cornea caused by infection.

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Persistent Ocular Pain

Patients with RCE often experience months or years of eye pain after the initial injury.

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Basement Membrane

A layer beneath the corneal epithelium that helps attach the cells together.

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Herpes Zoster Keratitis

An infection of the cornea caused by the varicella-zoster virus (VZV), which also causes chickenpox.

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Herpes Zoster Ophthalmicus

A condition that occurs when the varicella-zoster virus (VZV) reactivates and affects the trigeminal nerve, leading to a characteristic skin rash and potential ocular complications.

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HSV Stromal Keratitis

A serious complication of herpes zoster ophthalmicus, involving inflammation of the cornea's deeper layers.

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Dendritic Ulcer

A corneal ulcer with a characteristic branching pattern, commonly caused by herpes simplex virus (HSV) infection.

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Acanthamoeba Keratitis

A rare but serious corneal infection caused by Acanthamoeba, a type of amoeba.

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Herpes Zoster Ophthalmicus Ocular Involvement

Inflammation affecting various structures of the eye, including the cornea, iris, and choroid, often associated with herpes zoster ophthalmicus.

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Neurogenic Motility Disorders

A condition that occurs when herpes zoster ophthalmicus involves the nerve that controls eye movements, potentially leading to difficulty moving the eye.

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Scleritis

Inflammation of the sclera, the white outer layer of the eye, often linked to herpes zoster ophthalmicus.

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Varicella (Chickenpox)

The initial infection caused by the varicella-zoster virus (VZV), resulting in chickenpox.

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Herpes Zoster (Shingles)

The reactivation of the varicella-zoster virus (VZV), which causes shingles (Herpes Zoster).

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Lipid Layer of Tear Film

A thin oily layer of the tear film that prevents excess evaporation, produced by the meibomian glands.

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Aqueous Layer of Tear Film

The middle layer of the tear film, composed of water and electrolytes, and produced by the main and accessory lacrimal glands.

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Mucin Layer of Tear Film

The innermost layer of the tear film, responsible for adhesion to the corneal epithelium, produced by the conjunctival goblet cells.

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Dry Eye Disease

A condition caused by an imbalance in the tear film, leading to dryness and discomfort. Symptoms include blurry vision, eye irritation, and a feeling of grittiness.

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Aqueous Deficient Dry Eye

A type of dry eye disease where the tear film lacks sufficient aqueous layer. This is often due to decreased production by the lacrimal glands.

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Nocturnal Epithelial Disruption

A condition where the epithelial layer of the cornea becomes disrupted, commonly occurring at night, leading to symptoms like a corneal abrasion.

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Bilateral Nocturnal Epithelial Disruption

Bilateral symptoms often suggest a corneal epithelial dystrophy, indicating an abnormal attachment of the epithelium to the basement membrane.

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Foreign Body Sensation

A sensation of a foreign object on the cornea, commonly experienced during nocturnal epithelial disruption.

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Photophobia

Pain or discomfort when exposed to light, a common symptom of nocturnal epithelial disruption.

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Blepharospasm

Involuntary eyelid closure, often observed in nocturnal epithelial disruption.

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Decreased Vision

Reduced clarity of vision, a hallmark of nocturnal epithelial disruption.

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Lacrimation

Excessive tear production, a typical response to corneal irritation.

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Duration of Nocturnal Epithelial Disruption

The duration of an episode of nocturnal epithelial disruption, typically ranging from seconds to minutes, rarely lasting hours.

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Trigger for Nocturnal Epithelial Disruption

The occurrence of symptoms upon waking from sleep or after eye rubbing in the morning, often associated with nocturnal epithelial disruption.

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Difficulty Opening Eyes

Patients describe difficulties opening their eyes after waking, a characteristic symptom associated with nocturnal epithelial disruption.

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Symptom Location

Symptoms localized to the eye previously affected by injury, highlighting the potential for persistent issues.

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Management of Nocturnal Epithelial Disruption

Treatment primarily focuses on lubrication, aiming to protect and support the corneal epithelium.

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Lubrication

Simple eye ointments or Lacri-Lube are often used to lubricate the eye and alleviate dryness during nocturnal epithelial disruption.

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Duration of Lubrication

Patients should use lubricants throughout the day, typically for at least three months after the last symptoms to ensure the epithelium fully attaches to the cornea.

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Severe Case Management

In severe cases of nocturnal epithelial disruption, medications like cyclopentolate 1% and chloramphenicol 1% may be used.

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Evaporative Dry Eye

Dry eye disease caused by insufficient tear production due to the evaporation of tears from the ocular surface. It is characterized by symptoms like dry eyes, burning sensation, and gritty feeling.

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Inflammatory Disease Associations with Dry Eye

A group of autoimmune diseases that can cause dry eye, including Sjogren's Syndrome, Rheumatoid Arthritis, Systemic Lupus Erythmatosus, and Scleroderma.

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Punctal Plugs

A procedure where small plugs are inserted into the tear drainage system (puncta) to reduce tear outflow and increase tear retention on the ocular surface.

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Reduced Tear Meniscus

A common sign of dry eye where the tear meniscus, normally present at the lower lid margin, is significantly reduced or absent.

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Tear Break-Up Time (TBUT)

A test used to measure how long tears stay on the surface of the eye. A shorter than normal tear break-up time (TBUT) indicates increased tear evaporation.

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Punctate Epithelial Keratopathy (PEK)

Tiny dots or lesions on the corneal surface, often seen in dry eye, indicating damage to the corneal epithelium.

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Mucin Deficiency

A type of dry eye characterized by the formation of stringy, mucus-like strands on the ocular surface, sometimes causing blurry vision.

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Dacryocystitis

Inflammation of the lacrimal sac, often occurring due to blockage of the nasolacrimal duct.

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Acute Dacryocystitis

An acute infection of the lacrimal sac, often characterized by sudden onset of pain, redness, swelling, and purulent discharge.

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Chronic Dacryocystitis

A chronic inflammation of the lacrimal sac, leading to the formation of a cyst filled with mucoid material.

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Epiphora

Excessive tearing or overflow of tears.

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Temporary Partial Tarsorrhaphy

A condition where the upper and lower eyelids are partially sewn together to protect the cornea from exposure and promote tear retention.

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Canthal Sling

Also known as 'lid tightening' or 'lid tightening'.

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Dacryocystorhinostomy

A surgical procedure to create a new pathway for tears to drain from the eyes into the nose.

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Balloon Dacryocystoplasty

An alternative treatment for nasolacrimal duct obstruction, where a balloon is inserted into the duct to widen it.

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Study Notes

Microbial Keratitis

  • Arises from various pathogens and triggers a range of host responses.
  • Bacterial, fungal, acanthamoeba, viral, and marginal keratitis are subtypes.
  • Bacterial keratitis subtypes include Staphylococcus Aureus, coagulase-negative staphylococci, Streptococcus species.
  • Fungal keratitis subtypes include Candida spp. and Fusarium spp., which can progress rapidly and invasively.
  • Viral keratitis involves Herpes Simplex Virus, Herpes Zoster Virus, Epstein Barr, Cytomegalovirus or Adenovirus..
  • Marginal keratitis is a specific type of inflammation.

Bacterial Microbial Keratitis

  • Rare in healthy eyes due to strong corneal defenses.

  • Common in immunocompromised individuals, poor contact lens hygiene, and after corneal surgery.

  • Disease progression can lead to endophthalmitis.

  • Symptoms include acute onset, severe pain, rapid progression, profuse tearing, photophobia, redness, discharge, and reduced vision.

  • Signs include: corneal ulcer, stromal deep with overlying epithelial loss, stromal abscess formation, corneal edema, activity with or without hypopyon, redness, upper eyelid edema, Descemet's membrane folds, corneal degradation, necrosis, and thinning, and scar formation.

  • Management involves immediate referral to HES, contact lens removal for culture, scraping the corneal base and margin of ulcer (to collect material for culture and remove necrotic tissue), in-hospital admission if compliance is poor, and antibiotic treatment.

Fungal Keratitis

  • Rare
  • Corneal trauma involving organic material, contact lens related, or contaminated contact lens solutions are potential causes.
  • Signs and symptoms are similar to bacterial conjunctivitis but progress more slowly.
  • Management involves referral, corneal scraping and PCR testing, anti-fungal drops, and systemic therapy.

Acanthamoeba Keratitis

  • Linked to contact lens wear, inadequate lens disinfection, and use of tap water in lens storage.
  • Management involves stopping lens wear, appropriate disinfection, and referral.
  • Treatment involves a combination therapy and referral if cases are severe.

Viral Keratitis

  • Caused by herpes simplex virus, herpes zoster virus, cytomegalovirus, adenovirus, and Epstein Barr.
  • Herpes simplex virus can occur in an intact epithelium.
  • Symptoms may include unilateral red eye, pain, photophobia, epiphora, reduced vision, and possibly secondary uveitis.
  • Management may involve ceasing lens wear, and antibiotic or antiviral medications, and referring a patient to a healthcare professional immediately.

Corneal Trauma

  • Significant eye injury that may involve an object and/or inflammation.
  • Symptoms include pain, foreign body sensation, photophobia, tearing, and decreased vision.
  • Treatment options include removal of foreign objects, antibiotic prophylaxis, and monitoring for healing.

Recurrent Corneal Erosion

  • Repetitive disruption of the corneal epithelium.
  • Causes include mechanical trauma or corneal abrasion by a fingernail.
  • Management includes treating the underlying cause, relieving symptoms (e.g., by using lubricating drops), and monitoring for healing.

Lacrimal Disorders

  • Keratoconjunctivitis Sicca (dry eyes disease), dacryocystitis, and epiphora are included in this category,
  • Tear film abnormalities and or diseases of the tear glands cause symptoms.
  • Causes include various factors that disrupt tear production, drainage or viscosity.

Acute Dacryocystitis

  • Bacterial infection in the lacrimal sac (often secondary to nasolacrimal duct blockage).
  • Symptoms include sudden pain, erythema, edema around the lacrimal sac, and purulent discharge.
  • Management involves antibiotics and may include referral.

Chronic Dacryocystitis

  • Formation of a mucocele in the lacrimal sac.
  • Symptoms include swelling, tenderness, redness, and epiphora (excessive tearing).
  • Management depends on the progression of the condition and may include warm compresses and referral.

Epiphora

  • Tears overflow, frequently seen in elderly patients.
  • Causes include tear production exceeding drainage capacity.

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Description

This quiz covers the various types of microbial keratitis, including bacterial, fungal, viral, and marginal keratitis. It focuses on the pathogens involved, symptoms, and the risk factors associated with each subtype. Test your knowledge on this important topic in ophthalmology.

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