Both b and c
- The interpretation of the given placido disc test is Normal.
- It is one of the tests conducted to study the shape of the corneal surface(Corneal topography).
- Consists of equally spaced alternating black and white rings with a hole in the centre to observe.
The following results may be seen on examination:
- Areas where the mires appear closer together – steeper corneal curvature
- Areas where mires are more widely spaced – flatter corneal curvature
- Distinct, well-formed mires – regular and smooth surface.
Placido disc interpretations in various conditions:
Note: Distortion of the circle is seen in keratoconus, keratoglobus, corneal ulcer, and corneal abrasion.