In keratometry, the horizontal reading is taken from which side, and the vertical from which side?

In keratometry, the horizontal reading is taken from which side, and the vertical from which side?

• A. Horizontal from left; vertical from right
• B. Horizontal from top; vertical from bottom
• C. Horizontal from right; vertical from left
• D. Horizontal from left; vertical from top

Answer: (C)

In keratometry, you’re reading the curvature of the cornea along two principal meridians, using the instrument’s fixed reticle scales. Because the keratometer’s optical image is inverted, the scales are read from the side that corresponds to each meridian in that inverted view: the horizontal meridian is read from the right side, and the vertical meridian is read from the left side. This convention lets the horizontal and vertical readings align with the corneal reflections correctly. Therefore, the horizontal reading from the right and the vertical reading from the left is the correct approach.

In keratometry, you’re reading the curvature of the cornea along two principal meridians, using the instrument’s fixed reticle scales. Because the keratometer’s optical image is inverted, the scales are read from the side that corresponds to each meridian in that inverted view: the horizontal meridian is read from the right side, and the vertical meridian is read from the left side. This convention lets the horizontal and vertical readings align with the corneal reflections correctly. Therefore, the horizontal reading from the right and the vertical reading from the left is the correct approach.