purkinje images

this presentation provides information regarding purkinje image definition, formation, and their cross section, and their clinical significance.

1. Purkinje images 16immo11 Rashda Rahman

2. Mode of image formation:- Images are formed due to reflection and refraction Purkinje images are formed due reflection of light in the eye. 4 purkinje images are formed in the eye

3. 1 st purkinje image formed due to anterior cornea ( convex) Image formed due a.cornea is virtual and erect Image is formed nearer to anterior surface of lens and next to the 2 nd image 2 nd purkinje image is formed by posterior cornea( convex) It is virtual and erect image formed nearer to anterior surface of lens and front of first image 3 rd purkinje image is formed by anterior surface of lens(convex) Image is formed next to 4 th image almost in vitreous.H Virtual and erect

4. 4 th purkinje image is formed by posterior surface of lens(concave) Its tha only real and inverted purkinje image Present back to the 3 rd image Nearer to posterior lens surface

5. Importance of purkinje images Purkinje image 1 has many important clinical applications, including kerotometry and corneal topography Used in measuring angle kappa(angle of deviation) in Hirschberg test

6. 1 st purkinje image is about 3.90 mm right to anterior cornea Can find using formula F=-2/r and vergence relation L’=L+F The first and fourth Purkinje images are used by some eye trackers, devices to measure the position of an eye. Eye tracking is the process of measuring either the point of gaze (where one is looking) or the motion of an eye relative to the head. An Purkinje Image Tracking The first and fourth Purkinje images can be used for tracking the direction of gaze by the Dual-Purkinje Image technique, which uses the relative positions of these reflections to calculate the direction.