Corneal Infiltrative Events Notes

Corneal Infiltrative Events

Learning Outcomes

  • Recognize and describe the symptoms, signs, aetiology, and management of:
    • Corneal Infiltration / Infiltrative Keratitis
    • Culture Negative Peripheral Ulcer
    • Contact Lens Induced Acute Red Eye (CLARE)

Corneal Infiltrative Events (CIEs)

  • Definition: Inflammatory event terminology.
  • Key Feature: Infiltration or migration of cellular elements into the cornea.
  • Historical Context: CIE was sometimes associated with lesser severity to differentiate it from Microbial (Infectious) Keratitis, but this is not strictly accurate.

Classification of CIEs

  • Sweeney et al (2003)
  • Reference: Sweeney DF, Jalbert I, Covey M et al. Clinical characterization of corneal infiltrative events observed with soft contact lens wear. Cornea 2003; 22.

Manchester Keratitis Study (Efron et al)

  • Distribution of clinical severity scores for CIEs with respect to wearing modality and lens type.

Position of Infiltrates (Manchester Keratitis Study)

  • Size and location of infiltrates for all wearing modalities and lens types.
  • The large outer circle represents a 12mm diameter cornea.
  • Data from left eyes have been horizontally mirror transposed so that all infiltrates are represented as if for the right eye only (T = Temporal, N = Nasal).

Types of CIEs Mentioned in Manchester Keratitis Study

  • MK - Microbial Keratitis
  • CLPU - Contact Lens Peripheral Ulcer
  • CLARE - Contact Lens Acute Red Eye
  • IK - Infiltrative Keratitis

Infiltrative Keratitis

  • Definition: Accumulation of white blood cells in the cornea.
  • Classification: Based on location (e.g., sub-epithelial or stromal).
  • Important Note: May be a key sign of infectious keratitis.

Signs of Infiltration

  • Discrete/focal spots in the cornea or diffuse band of haziness near the limbus.
  • Grey, dull, grainy appearance.
  • Generally sub-epithelial, almost always in the anterior half of the stroma.
  • Often located in proximity to local bulbar conjunctival and limbal hyperaemia.

Aetiology of Infiltration

  • Multifactorial: Multiple potential causes; clinician must evaluate to determine the primary cause(s).
    • Mechanical trauma
    • Viral
    • Allergic responses
    • Solution toxicity
    • Hypoxia
    • Lens deposits
    • Poor hygiene
    • Tight lens fit
    • Idiopathic

Management of Corneal Infiltration

  • Cease lens wear until infiltrates resolve.
  • Alleviate mechanical trauma.
  • Loosen lens fit.
  • Improve oxygen performance.
  • Improve lens hygiene.
  • Alter solution / care system.
  • Prognosis: Good for recovery if the visual axis is not involved.
  • Medical Treatment: Indicated if infiltrates encroach on the visual axis or do not resolve following lens removal.
    • Involves the use of prophylactic antibiotics and steroids.

Culture Negative Peripheral Ulcer (CCLRU/CLPU)

  • Alternative name: Contact Lens-related Peripheral Ulcer (CLPU).
  • Definition: Non-infectious infiltrative response to bacterial toxins.
  • Usually associated with soft extended lens wear.
  • Typically monocular.
  • Likely to leave a small peripheral scar.

Culture Negative Peripheral Ulcer Symptoms

  • Mild-moderate ocular discomfort or foreign body sensation (i.e., not painful).
  • Mild photophobia.
  • Increased lacrimation.

Culture Negative Peripheral Ulcer Signs

  • 1-2 small round epithelial lesions in peripheral cornea.
  • Clearly defined margins, 0.2-1.0mm in size.
  • Infiltrates surrounding the lesion.
  • Usually noticed by the patient, but not always.

Culture Negative Peripheral Ulcer Management

  • Cease lens wear immediately.
  • Ocular lubricants.
  • Prophylactic topical antibiotic.
  • Key Consideration: If in doubt as to whether infectious or sterile, treat as infectious due to potential consequences.
  • Review in 24 hours.
  • Recurrence: Likely; counsel on further extended wear.
  • Consider daily disposables.

Contact Lens Induced Acute Red Eye (CLARE)

  • Definition: Inflammatory reaction of the cornea and conjunctiva, usually following overnight lens wear.
  • Rare in daily wear, infrequent in extended wear.
  • 10% of cases may be bilateral.

Contact Lens Induced Acute Red Eye Symptoms

  • In mild form, patient notices the problem upon waking.
  • In severe cases, the patient is awakened in the early hours of the morning with extreme unilateral pain.
  • Photophobia and lacrimation.
  • Patient then notices they have a red eye.

Contact Lens Induced Acute Red Eye Signs

  • Marked bulbar and limbal conjunctival hyperaemia.
  • Little / no lens movement upon initial examination.
  • Debris may be visible trapped beneath the lens.
  • Epithelial staining detected following lens removal.
  • Slit lamp examination reveals small sub-epithelial infiltrates near the limbus.
  • Other transient signs may include anterior chamber flare and low-grade neovascularization.

Contact Lens Induced Acute Red Eye Aetiology - Multifactorial

  • Tight-fitting extended wear soft lens.
  • Inflammatory toxic effects from trapped debris.
  • Mechanical irritation from poor lens design.
  • Irritative response to acute hypoxia or lens deposition.
  • Hypersensitivity / toxic reaction to solution preservatives.
  • Tear film thinning.

Contact Lens Induced Acute Red Eye Management

  • Cease lens wear! CLARE resolves quickly, and infiltrates clear within a few weeks.
  • Prophylactic antibiotic drops/cream.
  • When the condition is fully resolved, refit with daily wear / disposable lenses.
  • Consider lens design and fit, Dk/t, non-preserved care system.
  • Careful monitoring - CLARE can recur.
  • Potential for infective keratitis following CLARE is high.

Further Reading

  • Efron N (2019) Contact Lens Complications 4th Edition. Philadelphia. Elsevier (Chapters on Corneal Infiltrative Events and Microbial Keratitis)
  • Efron N & Morgan P (2006) Rethinking contact lens associated keratitis. Clin Exp Optom 2006; 89: 5: 280–298.
  • CCLRU/LVPEI Guide To Corneal Infiltrative Conditions.