When performing Hirschberg testing, which Purkinje image is generated?

Hirschberg testing is a clinical test used to assess the alignment of the eyes and to determine the presence and magnitude of strabismus. This test relies on the reflection of light from the cornea, known as the Purkinje images. There are four Purkinje images, but the first one (PS 1) is the most relevant in the context of Hirschberg testing.

When light is shone onto the cornea, the first Purkinje image, which is formed by the reflection from the anterior surface of the cornea, is utilized in this testing. The location of this reflection relative to the pupil is indicative of eye alignment. If the reflection falls centrally within the pupil, it suggests that the eyes are aligned. Any deviation from this central position can indicate misalignment or a strabismus condition.

PS 1 is important in this context because it provides direct, visual feedback on where the eyes are positioned in relation to each other. This makes it the primary Purkinje image used in the Hirschberg test. Understanding the significance of PS 1 helps practitioners evaluate ocular alignment effectively during an examination.