内视现象

内视现象（Entoptic phenomenon）是一种由人眼本身的内部造成的视觉效果。（有时也称为entopic phenomenon ，可能是印刷错误。）
用亥姆霍兹话来说：「在合适的条件下，落在眼睛上的光线可能致使我们得以看见眼睛内的某些物体。这些知觉称为「内视」（entoptical）。」

**概述**
内视影像所投射在视网膜上的影像有其物理基础，这与由视觉系统引起的视错觉不同，视错觉的特点是视知觉似乎与现实不同。内视影像则是由观察者自己眼睛内部的现象引起的，这种影像与视错觉和幻觉有个共同之处，观察者都无法与其他人分享对于这种现象的直接和特定的观点。
亥姆霍兹helmholtz说明了某些观察者可轻易看见而其他人却完全看不到的内视现象。这种差异不足为奇，因为产生这些影像的眼睛，在具体的层面上对每个人来说都是独一无二的。由于个体之间有所差异，加上两个观察者无法共享一个几乎相同的刺激，所以这些现象与大多数视觉感觉不同，也不同于大多数借由观察共同刺激所产生的视错觉。不过主要的内视现象之间有充足的共性，现在已能令人满意地解释其物理成因。

**例子**
内视效应的一些例子包括：

**参见**
 关于鬼的科学解释- 耳内现象（Endaural phenomena）- 结构衡量（Form Constant）- 临睡幻觉（hypnagogia）- 感觉剥夺箱（Isolation tank）- 囚人戏剧（prisoner's cinema）- 闪烁的视野缺损（scintillating scotoma）- 视雪症- 蓝天内视现象- 飞蚊症- 《论色彩学》（Theory of Colours）

**参考文献**
 Jan E. Purkyně, 1823: Beiträge zur Kenntniss des Sehens in subjectiver Hinsicht in Beobachtungen und Versuche zur Physiologie der Sinne, In Commission der J.G. Calve'schen Buchhandlung, Prag.- H. von Helmholtz, Handbuch der Physiologischen Optik, published as "Helmholtz's Treatise on Physiological Optics, Translated from the Third German Edition," ed. James P. C. Southall; 1925; The Optical Society of America.- Leonard Zusne, 1990: Anomalistic Psychology: A Study of Magical Thinking; Lea; 0-8058-0508-7  date=20071114212320 - Becker, O., 1860, “Über Wahrnehmung eines Reflexbildes im eigenen Auge About perception of a reflected image in your own eye,” Wiener Medizinische Wochenschrift, pp. 670 672 & 684 688.- M. Tscherning, 1920, Physiologic Optics; Third Edition, (English translation by C. Weiland). Philadelphia: Keystone Publishing Co. pp. 55–56.- White, Harvey E., and Levatin, Paul, 1962, "'Floaters' in the eye," Scientific American, Vol. 206, No. 6, June, 1962, pp. 199 127.- Duke Elder, W. S. (ed.), 1962, System of Ophthalmology, Volume 7, The Foundations of Ophthalmology: heredity pathology diagnosis and therapeutics, St. Louis, The C.V. Mosby Company. p450.- Snodderly, D.M., Weinhaus, R.S., & Choi, J.C. (1992). Neural-vascular relationships in central retina of Macaque monkeys (Macaca fascicularis). Journal of Neuroscience, 12(4), 1169-1193. Available online at: http://www.jneurosci.org/cgi/reprint/12/4/1169.pdf.- Sinclair, S.H., Azar-Cavanagh, M., Soper, K.A., Tuma, R.F., & Mayrovitz, H.N. (1989). Investigation of the source of the blue field entoptic phenomenon. Investigative Ophthalmology & Visual Science, 30(4), 668-673. Available online at: http://www.iovs.org/ date=20150322000208 .- Giles Skey Brindley, Physiology of the Retina and Visual Pathway, 2nd ed. (Edward Arnold Ltd., London, 1970), pp. 140–141.- Bill Reid, “Haidinger's brush,” Physics Teacher, Vol. 28, p. 598 (Dec. 1990).- Walker, J., 1984, “How to stop a spinning object by humming and perceive curious blue arcs around the light,” Scientific American, February, Vol. 250, No. 2, pp. 136 138, 140, 141, 143, 144, 148.

**外部连结**
 Entoptic+Vision-  Picture of the entoptic phenomenon: Vitreous Floaters date=20190612194449  (PDF file, requires an Acrobat Reader or plugin)-  Diagram of entoptic subjective visual phenomena date=20190613035528 -  Video describing history and science of first entoptic viewing technique date=20200226084909 -  Video describing history and science of second entoptic viewing technique date=20200410084537 -  The Relation Between Migraine, Typical Migraine Aura and “Visual Snow” date=20171225033640