Question

The visual axis of the eye is best defined as the line from the:

• A. Center of cornea to retina
• B. Object to fovea
• C. Center of lens to cornea
• D. None

Hint:

It is the line of sight from what you look at to the point of sharpest retinal vision.

Answer 1

The Correct Option is B

Step 1: The eye has two reference lines. The optical (anteroposterior) axis joins the centres of the cornea and the lens, while the visual axis is the functional line of sight.

Step 2: The visual axis is defined as the line joining the fixation point (the object being looked at) to the fovea centralis, passing through the nodal point of the eye. The fovea is the area of sharpest vision, so the eye is aligned to bring the image of the object precisely onto it.

Step 3: Matching this to the options, the description object to fovea is option b and is correct. The visual axis and the optical axis are not identical; they differ by a small angle (angle kappa or alpha).

Step 4: Center of cornea to retina and center of lens to cornea describe the optical axis components, not the line of sight, so they are wrong. Hence the visual axis runs from the object to the fovea.