User:YHLelis/沙盒
| Astigmatism | |
|---|---|
 | |
| Blur from astigmatic lens at different distances | |
| 分类和外部资源 | |
| 醫學專科 | Ophthalmology |
| ICD-10 | H52.2 |
| ICD-9-CM | 367.2 |
| OMIM | 603047 |
| DiseasesDB | 29648 |
| MedlinePlus | 001015 |
| MeSH | D001251 |
Astigmatism is a type of refractive error in which the eye does not focus light evenly on the retina.[1] This results in distorted or blurred vision at all distances. Other symptoms can include eyestrain, headaches, and trouble diving at night.[1] If it occurs early in life it can result in amblyopia.[2]
散光（又稱亂視，散光眼，Astigmatism）散光是眼睛的屈光不正常的一種徵狀，與投射在視網膜上的光線是否平均有關[1]。常見的徵狀有視線扭曲變形或視線模糊。散光患者看東西時會較難細微地看清景物。一般情況下，散光並不會獨自出現，患者的眼睛通常都會伴有近視或遠視。其他的徵狀包含眼睛容易疲勞，頭痛，且「無法從事夜間潛水」[1]。若在幼年時即患有此症，會導致眼睛弱視[2]。
The cause of astigmatism is unclear.[3] It is believed to be partly related to genetic factors.[4] The underlying mechanism involves an irregular curvature of the cornea or abnormalities in the lens of the eye.[1][3] Diagnosis is by an eye exam.[1]
目前散光的確切發生原因仍不清楚，部分專家認為與基因有關．散光的發生機制與角膜或水晶體的異常屈光度。规则散光多数是由于角膜先天性异态变化所致，还可能存在晶状体散光。也有些后天引起的散光，比如眼睑长针眼或粟粒肿，长期用眼姿势不良（如经常眯眼、揉眼、躺着看书等等），这样眼皮压迫角膜也会使角膜弧度改变，发生散光并使散光度数增加，另外，一些眼科手术如白内障及角膜手术也可能改变散光的度数及轴度。 不规则散光主要由于角膜屈光面凹凸不平所致，如角膜溃疡、瘢痕、圆锥角膜、翼状胬肉等。此症通常需要經過眼科檢查才能確診。
Three options exist for the treatment: glasses, contact lenses, and surgery. Glasses are the simplest. Contact lenses can provide a wider field of vision. Refractive surgery permanently changes the shape of the eye.[1]
目前常見三種治療方式為配戴眼鏡，隱形眼鏡和進行矯正手術。配戴眼鏡是最簡單的治療方式，配戴隱形眼鏡則可以提供較為寬廣的視野。若進行矯正手術則會永久地改變眼球形狀。
預防方法：
1. 最好3～4岁时做第一次全眼部检查，以后毎年定期眼部检查1～2次。指导幼童养成良好的卫生习惯，不随便用手或其化物品接触眼睛，以避免传染眼疾。看书时光线要充足，光线最好来自左后方；看书姿势要正确，并且保持在30公分至40公分之间的距离。
2. 选择读物时字体要清晰，不可太小。
3. 看电视须距离电视画面对角线的5～7倍。连续看书不超过一小时。需配眼镜者，应由医生或眼科視光師检查后配镜。
In Europe and Asia astigmatism affects between 30 and 60% of adults.[4] People of all ages can be affected.[1] Astigmatism was first reported by Thomas Young in the early 1800s.[3]
各年齡層的人都有可能患有此症。在亞洲和歐洲約有30-60%的成人都受到散光的困擾。此症是由Thomas Young於1800年初期所發表確認。
References
- ^ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Facts About Astigmatism. NEI. October 2010 [29 September 2016].
- ^ 2.0 2.1 Harvey, EM. Development and treatment of astigmatism-related amblyopia.. Optometry and vision science : official publication of the American Academy of Optometry. June 2009, 86 (6): 634–9. PMID 19430327.
- ^ 3.0 3.1 3.2 Read, SA; Collins, MJ; Carney, LG. A review of astigmatism and its possible genesis.. Clinical & experimental optometry. January 2007, 90 (1): 5–19. PMID 17177660.
- ^ 4.0 4.1 Mozayan, E; Lee, JK. Update on astigmatism management.. Current opinion in ophthalmology. July 2014, 25 (4): 286–90. PMID 24837578.