Is fluorescein staining always indicated in eye complaints that include likely conjunctivitis?

Fluorescein Staining in Eye Complaints with Likely Conjunctivitis

Fluorescein staining is not always indicated in eye complaints that include likely conjunctivitis, but should be performed when there is suspicion of corneal involvement or to rule out other ocular surface conditions. 1

When to Use Fluorescein Staining in Conjunctivitis

Indications for Fluorescein Staining:

• Suspected corneal involvement - When symptoms suggest possible corneal epithelial disruption:

  • Moderate to severe pain (beyond mild irritation)
  • Photophobia
  • Decreased visual acuity
  • Foreign body sensation that persists

• Specific types of conjunctivitis where corneal involvement is common:

  • Viral keratoconjunctivitis (especially adenoviral) - may show diffuse corneal and conjunctival staining 1
  • Gonococcal conjunctivitis - can rapidly progress to corneal involvement
  • Chlamydial conjunctivitis - may have subtle corneal involvement

• Differential diagnosis when presentation is atypical:

  • To distinguish from dry eye syndrome
  • To rule out corneal abrasion or foreign body
  • When symptoms are disproportionate to clinical findings

When Fluorescein Staining May Be Unnecessary:

• Typical bacterial conjunctivitis with:

  • Bilateral involvement
  • Mucopurulent discharge
  • No corneal symptoms
  • Normal visual acuity
  • Absence of severe pain

• Typical allergic conjunctivitis with:

  • Itching as predominant symptom
  • Clear watery discharge
  • No corneal symptoms

Technique for Proper Fluorescein Staining

When indicated, follow these steps:

1. Use saline-moistened fluorescein strips or 1-2% sodium fluorescein solution
2. Examine through biomicroscope with cobalt blue filter
3. Wait 1-2 minutes for optimal staining pattern visibility
4. Use yellow filter to enhance visualization if available 1

Interpretation of Findings

• Diffuse corneal and conjunctival staining: Commonly seen in viral keratoconjunctivitis and medicamentosa 1
• Inferior cornea and bulbar conjunctiva staining: Typically observed in staphylococcal blepharitis, meibomian gland dysfunction, lagophthalmos, and exposure 1
• Superior bulbar conjunctiva staining: Typically seen in superior limbic keratoconjunctivitis 1
• Exposure zone (interpalpebral) staining: Typically seen in dry eye disease 1

Important Caveats and Pitfalls

• Timing matters: Perform fluorescein staining before instilling other eye drops or manipulating the eyelids 1
• False negatives: Early Acanthamoeba keratitis may present with negative fluorescein staining despite epithelial irregularity 2
• Mild staining in normal eyes: Some degree of fluorescein staining can be observed in normal eyes, especially in the morning 1
• Medication effects: Systemic antihistamines like loratadine can cause ocular drying effects that may be detected with fluorescein staining 3
• Contact lens wear: Patients with conjunctivitis should be advised not to wear contact lenses 4

Alternative Staining Methods

When fluorescein is not ideal or additional information is needed:

• Rose bengal: Stains ocular surface cells lacking mucous coating and debris in tear film; more intense on conjunctiva than cornea; may cause ocular irritation 1
• Lissamine green: Similar staining profile to rose bengal but with less irritation; better for conjunctival evaluation than corneal assessment 1, 5

Remember that while fluorescein staining is a valuable diagnostic tool, clinical judgment should determine its use based on the specific presentation and suspected etiology of conjunctivitis.