Eye Redness

Introduction

Eye redness, or ocular hyperemia, is a common presenting symptom in Canadian primary care settings. As a future Canadian physician preparing for the MCCQE1, understanding the causes, evaluation, and management of eye redness is crucial. This guide will help you navigate this topic with a focus on Canadian healthcare practices and MCCQE1 exam preparation.

Etiology of Eye Redness

Eye redness can result from various conditions. Here's a breakdown of common causes you should know for your MCCQE1 preparation:

Canadian Epidemiology

Understanding the prevalence of eye redness causes in Canada is essential for the MCCQE1:

• Conjunctivitis is the most common cause, affecting about 1% of all primary care visits in Canada annually.
• Dry eye syndrome affects up to 29% of Canadians, with higher prevalence in colder regions.
• Seasonal allergies, which can cause eye redness, affect about 20-25% of Canadians.

Clinical Evaluation

When assessing a patient with eye redness for your MCCQE1 exam, remember the CanMEDS framework, particularly the roles of Medical Expert and Communicator. Follow these steps:

Differential Diagnosis

For MCCQE1 success, you must be able to differentiate between various causes of eye redness. Here's a comparison table to help you:

Management

The MCCQE1 will test your knowledge of appropriate management strategies. Here are key points to remember:

1. Viral Conjunctivitis:

   • Supportive care (artificial tears, cold compresses)
   • Advise on hygiene and contagiousness

2. Bacterial Conjunctivitis:

   • Topical antibiotics (e.g., erythromycin ointment)
   • In Canada, avoid over-prescribing antibiotics for likely viral cases

3. Acute Angle-Closure Glaucoma:

   • Emergent ophthalmology referral
   • Immediate pressure-lowering medications

4. Dry Eye Syndrome:

   • Artificial tears
   • Environmental modifications
   • Consider punctal plugs in severe cases

5. Chemical Injury:

   • Immediate and prolonged irrigation
   • Ophthalmology consultation

Canadian Guidelines

The Canadian Ophthalmological Society provides guidelines relevant to eye redness:

1. Conjunctivitis Management:

   • Emphasizes judicious use of antibiotics
   • Recommends viral PCR testing in select cases

2. Dry Eye Disease:

   • Staged management approach
   • Considers impact of Canadian climate

3. Glaucoma Screening:

   • Recommends routine screening for high-risk individuals over 50

Key Points to Remember for MCCQE1

• Differentiate between benign and sight-threatening causes of eye redness
• Know the appropriate use of diagnostic tools like fluorescein staining
• Understand when to refer to ophthalmology urgently
• Be familiar with Canadian guidelines on antibiotic stewardship in conjunctivitis
• Consider how Canadian climate affects conditions like dry eye syndrome
• Recognize the importance of thorough history-taking in eye redness cases

MCCQE1 Mnemonics

Remember the causes of painful red eye with "RASH UP":

• Refractive error (acute)
• Acute angle-closure glaucoma
• Scleritis
• Herpetic keratitis
• Uveitis
• Photophthalmia (UV keratitis)

Sample Question

A 45-year-old woman presents to her family physician in Toronto with a 2-day history of right eye redness, severe pain, and blurred vision. She also reports nausea and vomiting. On examination, her right pupil is mid-dilated and minimally reactive to light. Visual acuity in the right eye is significantly reduced compared to the left. Which one of the following is the most appropriate next step in management?

• A. Prescribe topical antibiotics
• B. Recommend artificial tears and cold compresses
• C. Perform immediate ocular irrigation
• D. Refer urgently to ophthalmology
• E. Order a CT scan of the orbits

Explanation

The correct answer is:

• D. Refer urgently to ophthalmology

This patient's presentation is highly suggestive of acute angle-closure glaucoma, a sight-threatening emergency that requires immediate ophthalmological intervention. The key features are:

• Acute onset of severe eye pain
• Associated nausea and vomiting
• Blurred vision
• Mid-dilated, poorly reactive pupil

In the Canadian healthcare system, family physicians play a crucial role in recognizing ocular emergencies and facilitating timely referrals. Acute angle-closure glaucoma requires urgent treatment to lower intraocular pressure and prevent permanent vision loss.

The other options are incorrect:

• A & B are appropriate for conjunctivitis, not for this emergency
• C is for chemical eye injuries
• E might be considered later but is not the immediate priority

Remember, the MCCQE1 often tests your ability to recognize and appropriately triage ocular emergencies in a primary care setting.

References

1. Canadian Ophthalmological Society. (2021). Clinical Practice Guidelines. Retrieved from https://www.cos-sco.ca/clinical-practice-guidelines/ (opens in a new tab)

2. Prokopich, C. L., et al. (2019). Ocular Disease in the Canadian Arctic. Canadian Journal of Optometry, 81(3), 15-22.

3. National Collaborating Centre for Indigenous Health. (2020). Eye Health and Vision Care. Retrieved from https://www.nccih.ca/495/Eye_health_and_vision_care.nccih?id=187 (opens in a new tab)

4. Ting, D. S. J., et al. (2021). Artificial intelligence for anterior segment diseases: Emerging applications in ophthalmology. British Journal of Ophthalmology, 105(2), 158-168.

5. Canadian Association of Optometrists. (2022). The Frequency of Eye Examinations Guideline. Retrieved from https://opto.ca/frequency-of-eye-examinations (opens in a new tab)