Certified Ophthalmic Technician Practice Test 2025 – Complete Exam Prep

The variance in corneal curvature measured with a keratometer indicates corneal astigmatism because it assesses the different curvatures of the cornea in different meridians. In a normal cornea, the curvature is spherical, meaning that the same curve exists in all directions. However, in corneal astigmatism, there are two different radii of curvature, which results in an uneven corneal surface.

When the keratometer shows different readings in various meridians, it suggests that the cornea has an irregular shape, leading to astigmatism. This condition can result in blurred vision as light rays are not focused evenly on the retina. Astigmatism can be derived from the natural shape of the cornea or can emerge due to other factors, but the key indicator is the variance in curvature when measured.

In contrast, corneal thickness, corneal opacity, and corneal degeneration pertain to different aspects of corneal health, such as the overall thickness of the corneal layers, presence of scarring or cloudiness, and the structural integrity of the cornea over time, respectively. These conditions do not directly relate to the curvature measurements and thus do not explain the variance noted on the kerat