弱视被误解的“关键期”

 

“It ain’t what you don’t know that gets youinto trouble. It's what you know for sure that just ain't so that is theproblem.”

——MARKTWAIN

“让我们陷入困境的不是无知,而是看似正确的谬误论断”

——马克·吐温

Mark Twain, the famous American author, issaying there are many things that are thought to be true that simply are not.This is certainly true in the area of the treating amblyopia and strabismus.The sad fact is that many traditional ophthalmologists and optometrists stillcling to outdated beliefs that recent scientific research has clearly shown tobe untrue. The even sadder fact is that many people are still subjected to old,invasive, and even damaging treatment while they could be helped but are notreceiving the necessary treatment.

美国作家马克·吐温说过,许多看似正确的观点,事实上是错误的。这种现象在斜弱视治疗领域也存在。尽管大量研究证明,许多传统的斜弱视治疗理念并不正确,但令人难过的是,很多传统的眼科医生和眼视光医生,仍在坚持这些过时的治疗理念。更令人难过的是,尽管已经有了更新、更有效的斜弱视治疗方法,但是,以错误理念为基础的侵入性、甚至是创伤性的治疗方案,仍在被广泛使用。

DEMYSTIFYINGTHE “CRITICAL PERIOD” |解读“关键期

There is no age limit totreat amblyopia and strabismus! So, why has it taken so long for the scientificcommunity to accept neural plasticity?

既然斜弱视治疗没有年龄限制,那么,为什么“大脑神经可塑性”这一观点,要经过如此长的时间,才得到主流学术界的认可?

In 1981, Drs. TorstenHubel and David Wiesel won the Nobel Prize in Physiology and Medicine fortheir experiments on the visual cortex of cats and monkeys.

1981年,托尔斯滕·胡贝尔博士和 戴维·魏塞尔博士,由于对猫和猴子大脑视皮层的研究成果,获得了该年诺贝尔生理与医学奖。

In their studies, the Nobel Prize winnersdemonstrated that cats and monkeys deprived of vision in one eye could regainvisual function in that eye but only during a specified period in early lifeknown as the critical period. After this time, it was felt that recovery wasnot possible. The results of these experiments, conducted on animals, were thenextrapolated to humans, and it was said that the critical period for vision inhumans lasted only until 7 or 8 years of age. After that, nothing could be doneto improve vision because neural plasticity was lost.

他们以年幼的猫和猴子为实验对象,研究发现,剥夺动物单眼视力一段时期后,这只眼的视功能还能恢复。但前提是,解除剥夺是在发育的早期阶段,即所谓的关键期。过了这段时期后,视功能就无法恢复了。随后,这项研究结果被推论到人类身上。推论认为,人类视觉发育的关键期,只持续到7岁或8岁,在此之后,由于大脑神经失去可塑性,视功能将无法恢复。

It is very important to bear in mind thatcats and monkeys are not humans, and were not treated with any form of visiontherapy. It is also important to understand that the conclusions drawn from theexperiments equated critical period of development with critical period inrehabilitation. This is an incorrect assumption and one which was never made byHubel and Wiesel. This incorrect assumption has hurt many patients and shouldhave never been made! In fact, subsequent scientific experiments on cats byDuffy, Snodgrass, et al. as well as by Kratz and Spear clearly demonstratedthat vision can be regained, sometimes very rapidly, even after the criticalperiod.

请注意,猫和猴子不是人类,这些动物也没有接受过,任何形式的视觉训练。同样值得注意的是,这些推论,把视觉发育的关键期,假设等于视觉康复的关键期。这个假设并不成立托尔斯滕·胡贝尔戴维·魏塞尔博士,也从未做出过这样的假设。这个错误的假设伤害了许多斜弱视患者!这样的悲剧本不应该发生。事实上,随后一系列的实验证明,即使过了关键期,猫的视功能也可以恢复,有时甚至恢复很快。进行这些实验的人包括,杜菲和斯诺德格拉斯的团队,以及克拉茨和斯皮尔的团队。

Another important point concerning theconcept of critical periods is explained by Dr. Susan Barry in the a blog onPsycology Today called, Eyes on the Brain. Dr. Barry pointed out that in Hubeland Wiesel’s experiments, the animals’ eyelids were sewn closed, so they didnot receive any form of vision through the closed eye. While this manipulationsimulates form deprivation amblyopia caused by a congenital cataract orcomplete ptosis (droopy eyelid completely covering the eye), it does notsimulate functional amblyopia. Only about1% of all the people with amblyopiasuffer from deprivation amblyopia. The critical period experiment does notapply to 99% of those with amblyopia.

在《每日心理学》上,苏珊.巴里博士也提到了关键期的问题。她指出,在胡贝尔和魏塞尔的实验里,动物的眼睑被完全缝合,被缝合的眼看不到任何东西。虽然,这个实验模拟了形觉剥夺性弱视,即先天性白内障或上睑下垂(上眼睑下垂,完全覆盖眼睛)引起的弱视,但是,该实验并没有模拟功能性弱视。弱视患者中,只有大约1%是行觉剥夺性弱视。因此,对于99%的弱视患者,这个关键期实验的结论并不适用。

文章摘自: CROSSED & LAZY EYES MYTHS,MISCONCEPTIONS AND TRUTHS)