How is a slit-lamp exam performed for uveitis?

Updated: Jan 15, 2019
  • Author: Monalisa N Muchatuta , MD, MS; Chief Editor: Gil Z Shlamovitz, MD, FACEP  more...
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Answer

Slit-lamp examination is performed as follows:

  • Examine the cornea by direct illumination with a broad beam at a 30°-40° angle between the viewing microscope and the light source.
  • Examine the epithelium for abrasions, edema, ulcers, or foreign bodies.
  • Inspect the stroma for deep ulcers and edema.
  • Scan the endothelium for keratitic precipitates (white blood cells on the endothelium), a hallmark of iritis (see the image below). Small to medium keratitic precipitates are classified as nongranulomatous, whereas granulomatous keratitic precipitates are large and have a greasy or "mutton-fat" granular appearance.
  • The most important structure to examine is the anterior chamber, which is bound by the cornea and the iris and is filled with aqueous humor. Examine the anterior chamber using a vertically and horizontally short beam. Normally, the aqueous humor is optically clear. In uveitis, however, an increase in the protein content of the aqueous causes an effect upon examination known as flare, which is similar to that produced by a moving projector beam in a dark smoky room.
  • White or red blood cells may be observed in the anterior chamber and are graded on a scale of 1+ to 4+, as follows:
    • 0 - None
    • 1+ - Faint (barely detectable)
    • 2+ - Moderate (clear iris and lens details)
    • 3+ - Moderate (hazy iris and lens details)
    • 4+ - Intense (fibrin deposits, coagulated aqueous)
  • White blood cells that layer in the anterior chamber are called hypopyon.
Small stellate keratic precipitates with fine fila Small stellate keratic precipitates with fine filaments in a patient with Fuchs heterochromic iridocyclitis.

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