What illumination technique utilizes a 2-4mm slit of light aimed at the limbus to observe corneal characteristics?

The technique that uses a 2-4mm slit of light aimed at the limbus to observe corneal characteristics is known as sclerotic scatter. This method involves directing a narrow beam of light across the cornea, which highlights any irregularities or opacities by causing them to scatter light. When light passes through the limbus and intersects with the corneal surface, variations in thickness, hydration, or irregularities can become visible, enhancing the clinician's ability to assess conditions such as edema or dystrophies.

This approach is particularly useful because it allows for the examination of the cornea's structure and integrity without causing significant discomfort to the patient. The scattered light creates a contrast between areas of normal and abnormal corneal tissue, making it an essential tool for optometrists and ophthalmologists in their evaluations.