What is expected to be seen under a wood lamp in a case of corneal abrasion?

Corneal Abrasion Findings Under Wood's Lamp Examination

When examining a corneal abrasion under a Wood's lamp, you will see the abraded area appear bright green due to fluorescein staining, which highlights the area of epithelial defect. 1

Examination Technique

• Apply fluorescein dye to the corneal surface, which will appear yellow under normal light 1
• When examined under cobalt blue light (Wood's lamp), the abraded area will fluoresce bright green, clearly delineating the area of epithelial loss 1
• The size, shape, and location of the abrasion can be accurately assessed using this technique 2

Specific Findings

• The abraded area will appear as a bright green area against the darker background of the intact cornea 1
• The borders of the abrasion will be clearly defined, allowing for measurement of the size (important for determining follow-up needs) 1
• The depth of the abrasion can be assessed by the intensity of the staining 2
• Pooling of fluorescein in areas of corneal thinning must be differentiated from actual epithelial staining 2

Additional Assessment

• Look for any foreign bodies that may be present on the corneal surface or embedded in the cornea 1
• Assess for any linear pattern of abrasion which might indicate a foreign body under the eyelid 2
• Evaluate for any stromal infiltration which could indicate infection rather than simple abrasion 2
• Check for anterior chamber reaction which may be present with more significant abrasions 2

Clinical Pearls and Pitfalls

• A Wood's lamp examination without fluorescein will not adequately reveal corneal abrasions - proper staining is essential 1
• Small abrasions (≤4 mm) without complications may not require follow-up if symptoms are resolving 1
• Larger abrasions or those with complications require 24-hour follow-up 1
• Contact lens-related abrasions require special attention and antipseudomonal antibiotic coverage 1
• Corneal abrasions typically heal within 24-72 hours; persistent symptoms warrant re-evaluation 3
• Failure to identify and remove foreign bodies can lead to persistent symptoms and delayed healing 1

Red Flags During Examination

• Deep stromal involvement or infiltrates may indicate infection rather than simple abrasion 2
• Hypopyon (pus in anterior chamber) suggests infectious keratitis requiring immediate treatment 2
• Alkaline pH of the eye (can be tested in the inferior cul-de-sac) may indicate chemical injury 4
• Complete corneal uptake of fluorescein rather than a localized area may indicate more severe injury 4
• Decreased visual acuity out of proportion to the abrasion size requires careful evaluation 1