I'm writing a story about the supernatural, except with as few "explained by magic" elements as possible. In the case of vampires, I want them to look as similar to humans as possible while being able to see at night as well as we can in the day. This rules out slit or hyperenlarged pupils. A taptum lucidum would be cool but it blurs vision. I read that maybe quickening the protein reaction in cones would work, but it wasn't explained whether that would negatively affect vision clarity. Also, I thought it would be interesting to change the cone frequencies so vampires can see red light more intensely, and also UV light. I believe uv vision in vampires would be beneifcial in warning them of the approaching dawn before its too late. If this means sacrificing some color vision between the two spectrum extremes I am perfectly alright with that. But that then raises the question of how the uv light will pass through the cornea and lens.

  • $\begingroup$ I read one person's story that they can see very very well in the dark and in a dark room they are blinded by the light coming from under the door. The doctors say there is nothing wrong with them though. I was hoping someone might be able to explain something along the lines of that and how to enhance it even further if possible. I don't know a whole lot about this kind of thing $\endgroup$
    – Jane Doe
    Apr 10, 2020 at 20:01

2 Answers 2


The human eye is very optimized to do what it does and that is detect various levels of light that you might find throughout the daytime; essentially dusk till dawn (pun intended). The frequencies that are eyes detect (visible spectra of colours) are not random either and are very in tune with sensing relevant information about the world which aids in survival. Likewise the light levels the eye can detect are very optimized for conducting business over the same period of the day.

Starting with the frequencies:

The reason that our eyes cannot see ultraviolet light very well is because these frequencies and are energetic enough to damage our eyes. So the eye contains an internal lens which filters these frequencies out; there are people who are born without these filters or lose them due to surgery report higher sensitivity to short wavelengths including the ability to see light ultraviolet sources, however, these people are at a higher risk of losing their eyesight due to cataracts. For vampires, I'm guessing they would want to avoid sunlight so it might be beneficial to be more sensitive to ultraviolet light, but I wouldn't see why this would necessitate an external change in appearance of the eye.

Infrared detection is a bit of a different case. Infrared wavelengths interestingly enough tend to be absorbed by materials to which visible light is transparent. For instance, Water and Glass allow visible light through, whereas these materials tend to strongly absorb infrared wavelengths. This of course is a general trend and differs on the exact composition of the material in question, but it is important because the eye is filled with water-based fluids which absorb most near-infrared wavelengths of light.

Some animals, like some snakes, can sense mid-Infra wavelengths to detect sources of heat, but these organs do not even remotely resemble an eye and are very short range (within a few meters). There are many reasons for this, part of this is because short wavelengths require extremely small apertures to focus the light, severely restricting the anatomy of the organ, and also because there are much better ways to see (eyes for example).

So while detecting near-ultraviolet may be a useful fairly practical thing for your vampires, without too much of a visual give-away, I do not see much use nor feasibility in detecting near infra-red.

Now to the question of seeing in low-light environments:

This is difficult because the only ways to enhance the ability to see in low-light environments is to either increase the amount of light allowed into eye (larger pupils) or to increase the light reflected within the eyes (taptum lucidum). Both these method will require visual changes to the eyes.

Increasing the concentration of rods over time to adapt to low level environments, would likely work without resulting in a significant change to the visual appearance of eye, but would still be far short of true night vision. Of course this would likely also affect colour vision and possibly visual acuity to some degree.

  • $\begingroup$ Ah sorry if I made it unclear. When I said "see red light more intensely" I meant to counteract the Perkinje effect, not to see infrared. Do you think quickening the protein destruction in the cones and the rods, and also packing them both more tightly would work? I don't know exactly how tightly they're packed already or any snowball effect type limitations on quickening the process. Or if a vampire would consume the necessary amount of the right kind of protein to sustain it $\endgroup$
    – Jane Doe
    Apr 10, 2020 at 20:40
  • $\begingroup$ Since the rods are optimized for light detection, with a reduced emphasis on resolution and information as opposed to the cones, I'd surmise that a higher concentration of rods would be beneficial for better vision in low light levels, but this would result in lower visual acuity as this would indicate lower reception by the cones. As regarding the biochemical interactions, these processes are notoriously complicated and it is unlikely that simple changes would be beneficial as these processes are highly optimized in biological systems. $\endgroup$
    – user110866
    Apr 10, 2020 at 21:47

How about taking an example from cats? Their pupils get very small when there is lots of light, and get much larger when it is dark. The structure of their eyes also helps them see prey better, which could be an advantage for your vampire.

  • $\begingroup$ From what I read, a cat has to have slit pupils in order for light to hit the multiple sites in their eyes. They're built that way because the shortening of the eye and the tapetum lucidum cause color scattering and blurriness and having multuple sites provides more input to clear up the picture. That'd make them look obviously not human. I was trying to avoid that if possible $\endgroup$
    – Jane Doe
    Apr 10, 2020 at 19:09
  • $\begingroup$ Makes sense. Depending on what time period this is set in, contact lenses might be an option. $\endgroup$
    – nighthawk
    Apr 10, 2020 at 19:31
  • $\begingroup$ Yeah. It would explain why vampires try so hard to stay away from people. The story is set from the year 1400 to the late 20th century. When sunglasses become invented it wouldnt be much of an issue but idk. I feel like a reader would think I'm trying to make them too much like cats $\endgroup$
    – Jane Doe
    Apr 10, 2020 at 19:35
  • $\begingroup$ Pupils can get very small. The issue would lie with them getting big enough. I want them to be uncomfortable in an environment brighter than the minimum of what is required to activate photopic vision in humans. And nearly blinded by your regular lightbulb $\endgroup$
    – Jane Doe
    Apr 10, 2020 at 19:52
  • $\begingroup$ Hmm. Big eyes? That could make enough space for smaller pupils, but it would look weird. $\endgroup$
    – nighthawk
    Apr 10, 2020 at 19:56

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .