What indicates a defect when examining the cornea with a light source?

The presence of a defect in the cornea can often be identified by a lack of reflection observed during examination with a light source. When the cornea is intact and healthy, it reflects light uniformly, leading to a shiny appearance. A defect, such as a scratch, ulcer, or other forms of corneal injury, disrupts this uniform reflection, resulting in the lack of reflection that can be observed during the examination.

A shiny appearance of the cornea typically indicates a smooth, intact surface, which is not associated with defects. Clear visibility of the underlying structures and the corneal surface also suggests normal conditions, as the transparency of a healthy cornea allows for unobstructed viewing of what's behind it. Bright redness can indicate inflammation or irritation, but it does not specifically point to a defect in the corneal surface itself. The lack of reflection, however, is a clear clinical sign that indicates some form of compromise or injury to the cornea, aligning closely with the examination findings related to corneal defects.