Читать книгу Essentials of Veterinary Ophthalmology - Kirk N. Gelatt - Страница 122

The optical part of the visual process ends with photons striking the outer segments of the photoreceptors. The neuronal part of the visual process begins with the capture of these photons and absorption of their energy by the photopigments in the outer segments of the cones and rods, where a chain of biochemical reactions starts. In addition to these sensory neurons, the retina also contains secondary and higher order neurons and an intricate neural circuitry that performs the initial stages of image processing before trains of electrical impulses are transferred through the axons of the retinal ganglion cells (RGCs) to areas in the brain where secondary processing and eventually visual perception occur. A schematic representation of the retina is shown in Figure 2.13.