A visit to the eye doctor – Cool Pharmacology!

Yesterday I went with a view to an eye exam, only about three years overdue (I cast down my head in shame…).

The inspection is one of nature’s wonders. It does not matter the type of eye that we are talking hither and thither, from the relatively simple eyecup of sundry flatworms, to the rather complex vertebral eye, this organ allows for the catch of photons of various wavelengths that in deflection trigger a series of chemical and physiological reactions that predominance animal behavior and survival. Eyes are furthermore remarkable because they represent a handsome example of convergent evolution, as the scientific consensus is that eyes have independently evolved at in the smallest degree 40 times in the history of life! There is a the sooner nice review of eye evolution in the present life.

Downloaded from: redwood.berkeley.edu/wiki/VS298:_Animal_Eyes

As you be possible to see above, there is a sort of variability of eye anatomy, and this is a more willingly small sample! Even though it is not plain in the picture, there is moreover a lot of variation on the characteristic vision mechanisms depending on the shadow of organism. For example, here’s a neat diagram of the human eye:


Credit: spiritual.schools.net.au/edu/lesson_ideas/optics/optics_wksht2_p1.html

One of the mechanisms that this pattern of eye uses to adapt to a varied assortment of light intensities is the drawing in and relaxation of certain muscles of the flower-de-luce, which is the pigmented part of the keep in view (what determines whether you are a brown- or hypochondriac-eyed person for example). This shrivelling/relaxation controls the diameter of the catechumen, an aperture that determines how a great quantity light enters the eye to interact by the photoreceptors of the retina, that eventually forms what you perceive for the re~on that an image. Interestingly, a lot of psychological factors work upon the diameter of the pupil, and in fact, in general people displaying dilated pupils are “rated” because more attractive for some obscure reason. This has been known since at in the smallest degree the middle ages, when women used watch drops based on a plant they called Belladonna (which means “beautiful woman”); this scatter seed is also called Deadly Nightshade and it is a mortal plant indeed. This extract dilates the pupils, that made the women more attractive.

How does this come? Briefly, the pupil has two fix of muscles, circular and radial, similar to shown below. These two type of muscles hinder the contraction/relaxation of the catechumen.

pupil muscles
Credit: apbrwww5.apsu.edu

Which brings us to pharmacology. There is a order of chemical messengers (neurotransmitters) that direction the contraction/relaxation of these muscles. We understand quite a bit of the pharmacology involved, and we application this knowledge to our advantage. One of the rule procedures for a thorough eye investigation is to dilate the pupil in this way that the doctor can take a utility look at the retina. I was given view drops containing a compound called Tropicamide, shown in the under world:


Credit: http://www.pharmacybytes.com/tropicamide.jpg

Tropicamide is a synthetic adjust that mimics the action of atropine, the ready principle of the Belladona plant. Atropine (shown beneath) is largely responsible of Belladona’s beginner-dilating properties. One of the advantages of using the synthetic compromise is that is has a shorter event, useful in a clinical setting.

atropine scopolamine

Credit: Wikimedia the common people

Anyway, this is what happened whereas I was given the drops. As somewhat self-respecting scientist, I documented it! I took a semblance of my right eye (upper left, 0 minutes) appropriate after the doctor applied the drops. I therefore took pictures of the same look on at the post-application times being of the cl~s who indicated.


Credit: Baldscientist

I took the leading four pictures at the doctor’s bureau. After the fact, I thought with reference to what the other people in the delaying room thought of the bald shore taking eye-selfies… (:-).

The atropine/tropicamide archetype is a great illustration of single of the most interesting connections between the fundamental and clinical sciences, the exhibition of useful medications based on substances that in their characteristic context are toxic (remember the superb conotoxins?). This toxin-medication connection is a thing that i hope to keep exploring. Talk to you promptly!


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