Broadly speaking, there are two types of amblyopia:
1.Organic*：This type of amblyopia is caused by disease in the eyes itself or in the visual (neurological) pathway. I will not address this type of amblyopia in this book because the treatment, if anything can be done at all, is medical in nature.
2.Functional: Functional amblyopia is a condition in which there is reduced sight (visual acuity), not due to disease, but rather to a treatable disruption in normal cortical visual function. Within this type of amblyopia, there are many causes, the most common are the following:
a)Refractive: Functional amblyopia, usually due to a difference in the refractive measurement (optical prescription) in one eye as compared to the other. I can also be due to an equal, but very high amount of atigmatism or refractive measurement in both eyes.
*The use of the term amplyopia in this situation often causes confusion. When we speak of amblyopia we are generally speaking of a condition that is not due to disease or pathology. But since it is written about in many textbooks it is included here. There is also a type of amblyopia, called hysterical amblyopia which arises from emotional factors. But since these conditions are not common and are written about in many textbooks they are mentioned here simply for completeness.
b) Strabismic: This occurs when one eye deviates (turns in or out) most or all of the time. To avoid double vision, vision is suppressed or turned off in the brain. Since the vision of the turned eye is not used, its function never develops to its full potential, resulting in amblyopia.
c) Mixed: In this type of amblyopia there are both organic and functional components, one superimposed on the other. With this type of amblyopia, it is often not possible to know how much improvement can be made until treatment is initiated and to know exactly when you have reached a limit where no further improvement is possible.
13.Monocular visual acuity test.
Copyright © 2011 版权所有：北京世纪合辉医药科技股份有限公司 All rights reserved