There are many viral skin infections. They range from the common to the rare, from the mild to the severe and from those causing just skin infection to those with associated systemic disease. The following is a brief account of a selection of the important viral skin infections. Many of the diseases mentioned here are covered in greater detail elsewhere and the reader is referred to appropriate links. Nonspecific viral rash. This is a widespread erythematous rash sometimes seen in viral infections. It is accompanied by the common symptoms of a viral infection, such as fever, headache and malaise. The rash usually develops rapidly. The appearance varies but commonly takes the form of an erythematous blotchy eruption. Local viral infections
The retina is the array of light receptor cells that lines the back of the eye. It contains two types of receptor cells, named after their shape; rod and cone cells, and interconnecting ganglion cells, of which there are two types with differing properties, X and Y cells.
Physiological blind spots are an anatomical fact. There are no receptors (rods and cones) where the optic nerve pierces the retina. The field of vision that falls on the physiologic blind spots is not received by the retinal receptors (no receptors in the optic disc-blind spot) and therefore not perceived by the cortex. Since we are binocular beings, the field of vision that falls on the blind spot of one eye is visualized by the contralateral eye.