# Any opthamalogists in the house?

**URL:** <https://boards.straightdope.com/t/any-opthamalogists-in-the-house/145706>\
**Category:** Factual Questions\
**Created:** [December 30, 2002, 5:28pm UTC](https://boards.straightdope.com/t/any-opthamalogists-in-the-house/145706 "2002-12-30T17:28:23Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![plnnr](https://avatars.discourse-cdn.com/v4/letter/p/7ea924/32.png) [@plnnr](https://boards.straightdope.com/u/plnnr)\
**Post date:** [December 30, 2002, 5:28pm UTC](https://boards.straightdope.com/t/any-opthamalogists-in-the-house/145706/1 "2002-12-30T17:28:23Z")

</div>

Why does squinting improve my vision when I dont’ have my contacts in or glasses on?

---

<div class="post-metadata">

**Author:** ![Bongmaster](https://avatars.discourse-cdn.com/v4/letter/b/6a8cbe/32.png) [@Bongmaster](https://boards.straightdope.com/u/Bongmaster)\
**Post date:** [December 30, 2002, 7:16pm UTC](https://boards.straightdope.com/t/any-opthamalogists-in-the-house/145706/2 "2002-12-30T19:16:16Z")

</div>

It tends to make the eye rounder which is what caused the distorted vision in the first place.

---

<div class="post-metadata">

**Author:** ![RipRiley](https://avatars.discourse-cdn.com/v4/letter/r/90db22/32.png) [@RipRiley](https://boards.straightdope.com/u/RipRiley)\
**Post date:** [December 30, 2002, 7:32pm UTC](https://boards.straightdope.com/t/any-opthamalogists-in-the-house/145706/3 "2002-12-30T19:32:36Z")

</div>

I like that a guy named Bongmaster explains distorted vision…funny

---

<div class="post-metadata">

**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\
**Post date:** [December 30, 2002, 7:37pm UTC](https://boards.straightdope.com/t/any-opthamalogists-in-the-house/145706/4 "2002-12-30T19:37:21Z")

</div>

I have heard this explanation before although I have never seen any evidence to back it up. I am not at all convinced that squinting applies pressure in such a way as to reshape the eyeball. I must disagree, though IANAO. I think this is more of a phenomenon of optics. Squinting is like stopping down a camera lens. The smaller the diaphragm, the greater the depth of field because the farther from the center of the lens the light enters, the more exagerrated its out-of-focusness will be. You can try this by punching a small hole in a piece of paper and looking through that instead of squinting, eliminating the possibility that this is due to any shape in the eye. A document at www.phy.olemiss.edu/~thomas/weblab/ 224\_web\_items/Exp26\_EyeModel.pdf explains this rather well.

---

<div class="post-metadata">

**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\
**Post date:** [December 30, 2002, 7:43pm UTC](https://boards.straightdope.com/t/any-opthamalogists-in-the-house/145706/5 "2002-12-30T19:43:02Z")

</div>

Whoops, extra space. Try this link.

---

<div class="post-metadata">

**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\
**Post date:** [December 30, 2002, 8:13pm UTC](https://boards.straightdope.com/t/any-opthamalogists-in-the-house/145706/6 "2002-12-30T20:13:04Z")

</div>

Not an ophthalmologist, but I’ve got a degree in optics. **Cooking with Gas** has it right. If you want to verify this, try looking through a small hole punched in something (a hole in a watchband works well). Stopping down the system with a smaller aperture means that the aberrations from off-axis rays are eliminated, but it’s at the ciost of the amount of lighht you get – the image is better, but dimmer. A few years ago somebody actually sold “eyeglasses” that worked on this principle.