What is specular reflection primarily used to examine?

Specular reflection is a technique that primarily utilizes a light source and a mirror-like surface, such as the corneal surface, to analyze the characteristics of that surface. In the context of examining the eye, specular reflection helps in evaluating the cornea's health and surface properties, which includes assessing conditions like corneal neovascularization. This condition refers to the abnormal growth of blood vessels into the cornea, which can be observed through the specular reflection method, allowing practitioners to see changes in corneal transparency and integrity.

While the other choices relate to important aspects of ocular health and contact lens evaluation, they do not specifically align with the capabilities of specular reflection. For example, lens thickness can be assessed using other measurement techniques, contact lens fit typically involves observing the lens on the eye with different methods, and pupil size is measured using tools and techniques like a pupilometer. Therefore, specular reflection's primary focus on the health and surface characteristics of the cornea makes it particularly suited for examining corneal neovascularization.