常见问题解答|概述
The retina is a delicate film containing rod and cone photoreceptor cells. It has the thickness of clear plastic wrap and the tensile strength of wet tissue paper. Vision originates in the retina. The photoreceptor cells convert light into electrical impulses and transport these impulses to the brain via the optic nerve for further processing. Diseases and anomalies of the retina may affect retinal function alone, or in some instances, the retina and its function are altered by disease that originates elsewhere. These conditions can cause the cells of the retina to malfunction or deteriorate over time, leading to a visual impairment. There are many types of retinal disorders and different kinds of visual deficits are encountered by patients with retinal disorders.
What is a retinal disorder?
A retinal disorder occurs when the retina malfunctions. In normal vision, the retina acts like the film in a camera. It is here where the pictures are created, so to speak, and then transmitted to the brain for interpretation.
Most disorders of the retina involve a disruption in the transmission of information from the photoreceptors to the brain. There are two types of photoreceptor cells: rods and cones. Rod cells function best in dim light and thus help us see in dimly lit environments. Cone cells function best in light and thus help us to see in daylight. Specifically, they are used for fine, detailed vision and allow us to perceive color. The cones are concentrated in the fovea, which is located at the center of the retina. Peripheral to the fovea, there is a higher concentration of rod cells and the cones are more widely spaced and interspersed within the rods.
What causes a retinal disorder?
视网膜有许多疾病，每种疾病都有其独特的特征，可能导致各种视觉缺陷。尽管遗传了许多视网膜疾病，但有些是由药物的不良影响或感染引起的。
Retinopathy of Prematurity (ROP)is a condition that occurs in premature infants, which results in problems with blood vessels that grow out of control along the retina. Some retinal disorders are related to illness, such as diabetes, while others can be caused by medications, such as seizure medications or chemotherapy, which can have a toxic effect on the retina.
Most retinal conditions fall into two broad categories: stationary and progressive. Even within these two groups there is a diverse mix of symptoms and severity of visual impairment. While stationary retinal diseases are present at birth, the level of vision loss remains the same over time. Examples of stationary conditions include Leber Congenital Amaurosis, which causes severe visual impairment, and congenital stationary night blindness, which results in decreased night vision. Progressive conditions may not be apparent at birth, but as time passes vision decreases. An example of this is Retinitis Pigmentosa, which results in a wide range of decreased vision.
视网膜疾病的症状是什么？
The symptoms of a retinal disorder vary widely from patient to patient, depending on the type of disorder, whether it is degenerative, where in the retina it originates, and whether it affects the rod or cone cells or both. Generally speaking, children and adults with a retinal disorder may experience any of the following symptoms:
- 晚上（夜失明）的视力差，从明亮的区域调整为昏暗的区域
- 突然或无法解释的视力丧失
- loss of peripheral vision
- loss of vision in a particular visual field
- nystagmus, a rapid, involuntary oscillatory motion of the eyeball
- photophobia, an abnormal sensitivity to or intolerance of light
Can retinal disorders be treated?
对于大多数视网膜变性（视觉丧失丧失的视网膜条件），无法治愈。但是，患者可以通过获得准确的诊断，详细的预后，低视觉辅助工具和遗传咨询而受益匪浅。在某些情况下，例如早产或黄斑变性的视网膜病变，激光手术可用于破坏异常的血管并防止进一步的视力丧失。