Leukodystrophy is one of a group of disorders characterized by degeneration of the white matter in the brain. The word leukodystrophy comes from the Greek roots leuko, white, dys, abnormal, and troph, growth. The leukodystrophies are caused by imperfect growth or development of the myelin sheath, the fatty covering that acts as an insulator around nerve fibers. When damage occurs to white matter, immune responses can lead to inflammation in the CNS, along with loss of myelin. The degenerat
A corneal laceration can be a partial- or full-thickness injury to the cornea. A partial-thickness injury does not violate the globe of the eye (abrasion). A full-thickness injury penetrates completely through the cornea, causing a ruptured globe. This topic discusses the full-thickness injury.
A compound eye may consist of thousands of individual photoreceptor units or ommatidia (ommatidium, singular). The image perceived is a combination of inputs from the numerous ommatidia (individual eye units), which are located on a convex surface, thus pointing in slightly different directions.he eye of a red-tailed hawk. Visual acuity, or resolving power, is the ability to distinguish fine detail and is the property of cone cells. It is often measured in cycles per degree (CPD), which measures an angular resolution, or how much an eye can differentiate one object from another in terms of visual angles.