Using a ‘Human Model’ to Examine the Vision of Albino Rats
Unless a question is directed towards vision, the thought of the underlying processes in which the eyes and brain perform together is never considered. So, if we were to analyze the underpinnings of vision what would we find? Would there be a simple network of interconnected neurons which simply convey information from the periphery to the brain? The art of seeing is very complex and is sensitive to conformational changes occurring in the eye. The loss of a particular type of photoreceptor can determine whether an individual is color-blind and/or a sudden decline in the eye’s normal level of a neurotransmitter may cause photosensitivity. Knowing that an aberration from the usual construct of the visual pathway can be responsible for several disorders directs attention to examining vision in albino rats. Experimental studies tend to use albino rats because of their passivity; it is interesting to note that albino rats and humans manifest similar symptoms for example, photosensitivity. Often drug testing or brain lesions are performed on animals to create animal models which are used to make generalizations to the human population. There are not many studies pertaining to the visual pathways in albino rats but since animal models are created to make inferences to humans, this paper proposes to use the ‘human model’ of vision to speculate the underlying problems between photosensitivity and the albino rat’s visual pathway.
Human Eye Model As mentioned before, the visual pathway consists of an elaborate network of neurons. In order to discuss photosensitivity, first we must look at the manner in which information is processed in the eye and relayed to the brain with the use of photoreceptors.
The development of the eye is very unique: it develops in an inside to out manner(1). From the rostral to caudal portion, the retina consists of the epithelium layer, photoreceptors, horizontal cells, amacrine cells and the ganglion cells (the ganglion endings make up the optic nerve). The structure is considered inside/out because light needs to pass through several layers before converging on the photoreceptors. The role and properties of the pupil and photoreceptors are key structures in relation to albinism. In the human eye, the pupil is made of melanin. Melanin is a photoreceptive pigment; when present it protects the eyes from ultraviolet light(2). After light passes through the pupil, cornea and other structures it converges on the back of the eye known as the retina.