The Misconceptions of Color Blindness 

I remember a classmate of mine writing about growing up colourblind, alongside his colourblind brothers. They'd occasionally visit the local farm to get vegetables, and their mother called them "the worst tomato pickers ever."

Over the course of 31 years, my late husband and I had so many arguments about color -- the house color, the walls, the curtains, the furniture, the car, etc. etc, etc. I thought he had terrible taste! Six years after his death we found out that I'm blue-yellow colorblind. Oops. My grown children then told me my own color choices were highly eccentric, but they didn't want to argue with me. Mostly we think it's pretty funny, but I would have let him choose the colors if I had known.

I would love to hear some stories of how ophthalmology into other specialties. As an example: all my mother’s doctors missed her having Neurofibromatosis. It was finally the ophthalmologist that suggested she be tested for NF mutation even though she had had a lot of lipomas removed through the years. Another wild one-my grandmother saw an ophthalmologist when she was in her mid 40s, and he referred her to a gynecologist. Something about her eyes cued the ophthalmologist that she might have endometriosis. We have wondered for years what tipped him off.

I always know I'm going to learn something when Knock, Knock, Hi/Eye drops.

Great topic and video!! My sister's family has the typical red-green color blindness (from her husband's family). Her daughter got the color blindness glasses for one of her son's when he was older. The expression on his face the first time he saw purple was priceless. They specifically waited until he was older so he could understand the limitations of the glasses. He does not wear them all the time, it does give him some control over his condition. Side note, one way she deals with her husband's color blindness is to decorate in blues and yellows and other colors he does see. She avoids simple green or red designs when possible.

Thanks again for having such detailed captions! You almost never see the ‘um’s and ‘uh’s captured anywhere else. All those subtle changes between the audio and the captions add up and the result can be incredibly disorienting. Caption writing is a difficult job, and I applaud you for giving it the attention it deserves.

After several years in continuous burnout, and inspired by your sketches, I decided to abandon A&E (accidents and emergencies, but most are pleople who I'd barely would consider any kind of ill)... and will start Pathology next month. I'm still a surgeon at heart, but we'll see how it goes. But still a surgeon.

I found the Dalton lens application extremely useful for getting understanding how color blind people see the world. It has a tool you can change the color space to allow color able people to experience contrast like color deficient vision.

Re: lensless existence, in 1978 I had a congenital cataract in my right eye removed at ~1yo and they just... never did anything further. (I know pediatric lens is differently shaped from adult lens, so that created a timeline, but my mother just never followed up?) Besides the part where there's no ability to focus, it's about half? as good as the peripheral vision in my good eye. I *can* see distinct stuff, big color differences and big light differences help distinguish shapes. I can tell hands have fingers, but unless they're nearly in touching range I can't tell how many are being held up, just that some are. Your video, for example, is a pinkish blob on top of a darkish shoulders triangle, in a brownish room blob, in a dark border. And, obviously, I don't have binocular vision, so no parallax, and no depth perception on the good side. Less obviously, I am permanently aware of the left side of my nose, and I have some small degree of visual perception into the ultraviolet range, albeit from the lenless eye. I understand that goes away with most later-life loss of lens as a function of brain filtering, but I have to suppose it was early enough in my life that my brain decided this was just what the world looked like: two different pictures, two different spectrums, permanent nose. (ETA: I got distracted! I'm mildly blue-green colorblind in the good eye, mildly enough that I didn't really realize there wasn't just 'a really wide range of aqua tones' and 'stoplights aren't usually considered to be blue-green' until I was an adult and asked other people. My brother is INTENSELY red-green colorblind, which we discovered together through the helpful efforts of Nintendo's Dr. Mario.)

Today I did my final presentation for my science class and it was on eyes and I included you telling the story of the origin of cataract lens replacements. Fingers crossed I get a good grade! 🤞

I’ve been working for optometrists off and on for about 13 years as an optician and optometric technician and I love Knock Knock Eye. I can always go to my docs and ask follow up questions and geek out with them about eyeballs, they always perk up! I’d be interested in learning more about VA changes post partum, or why corneal transplants are helpful for keratoconus vs scleral contacts.

I participated in an experiment where they tried different types of glasses and tests for my red-green colorblindness. Most fruszrating 2 hours of my life. But in the end the conclusion was, that my red-green colorblindness is that bad, that I don't really benefit from any of the glasses. There was one that kind of worked, but I would need to relearn the colors with it, for a really tiny benefit, that I could barely distingish.

We bought (we all-me, my two siblings, and my mom all chipped in for it) my dad, who has relatively bad red-green colorblindness, a pair of colorblind sunglasses. The site had him take a test first to identify type and severity and whatnot, and we all did it to convince him to as well (interestingly, I, a female, test positive for colorblindness pretty frequently, despite not testing as such as a young child). Anyways, he LOVES the sunglasses. Will wear them all the time on vacation and places he knows are supposed to have pretty colors. He loves the beach and holidays (esp. Christmas and Halloween) because of all the new colors. He’s like a little kid. He also had no idea that “macaroni yellow” is totally a thing. He kept trying to call it orange until we corrected him. However, and this is what’s interesting, we tried getting him the colorblind glasses since he loved the sunglasses so much, as we figured they would work much better than the sunglasses at night lol. But the glasses didn’t work. I can’t remember if he said there was no difference at all or just a negligible difference, but, either way, we ended up returning them. There are some other brands that are supposed to be marginally better for his kind of colorblindness, but they’re crazy expensive (even more so than the ones we’d already purchased) and you have to wear them for lengths of time for them to actually start working-and that’s if they work at all. We gave it up for a lost cause. He loves the sunglasses anyways.

So what happens if it the iris or sclera get injured? Does it affect your vision? Does it hurt? Also, could you do a video on Marfan's syndrome? Ophtalmologists like to drag in the med students to look at my Marfan eyes, so I assume it's a a relatively rare condition.

Thank you for this. There is a small but shocking still extant amount of people I have met who genuinely believe i basically look through a kaleidoscope all day

I didn’t know I was interested in eyeballs, but I’ve been enjoying these! I would be interested in an episode that gives a general overview of eye anatomy, maybe with that model you’d mentioned, if that’s possible. I sometimes have trouble keeping the terms straight!

My daughter is red-green color blind. She worked as a cashier during the Christmas rush at Walmart. Counterfeit $100 bills were passed and she could tell immediately that they were fake. She said that the bill looked orange to her compared to real $100 bills. "Like Monopoly money." They had her look through all the cashier's drawers and she found 3 more that had been accepted by other cashiers. They were supposed to use the marking pens but being the Christmas rush and the sheer number of shoppers they didn't catch it.

Thank you for explaining it so succinctly. It's hard to explain to people that it takes me a hot minute to distinguish the blue and purple stripes in a rainbow due to my colorblindness.

When my brother was in elementary school (he’s 55 now), I’ll never forget after he came home from school he broke down saying during his classrooms arts and crafts time, it was painting day..he couldn’t tell red from brown and I think if I remember (I’m five years older than him), he said he realized he was using brown to paint something but he thought it was red. He was too embarrassed to tell his teacher but he didn’t mention any kids making fun of him, the kids probably didn’t notice either since little kids just paint colorful blobs lol… but to my brother, it was a big deal. My mom talked to him to not worry, just keep painting and look at the colors first, but just have fun painting. He actually got a big happy face from his teacher saying great work when he went back to class. But that day, it really upset him because he didn’t know what was wrong with him and his vision. He could read from his classroom seat to the chalk board and see the letters just fine. This was in the early 80s and my mom had his eyes checked but she was told my brother’s eyes are just fine and he’ll grow out of it. Just test him on his colors. I guess he did ok after that and I think my mom talked to his teacher and she was sweet enough to privately let him know which was brown and red, blue and teal.. mostly just brown and red. Now at 55, my brother is struggling with aggressive mental illness for the last twenty years and he’s getting worse and he has been to several mental health facilities but they never keep him long enough to help him. And yet, he’s still so smart and the best rock drummer since he was a teenager. The brain really works in mysterious ways. Btw, a few of my male first cousins and one first female cousin on my mom side are also colorblind and they all have successful careers. 😁

I'm a videogame development student and an important aspect of that is learning about accessible design. I've had so many arguments with fellow students who wanted to do the lazy thing and use only color (mostly red/green) to differentiate between important elements in group projects. I even had to have this argument during the HCI course, where *not doing these things* was a criterium for passing!

As an Iowan, I love the shout out to U of I. We generally just want functional not perfect. My son was also found to be color blind at 4-5 years old, probably passed on from my dad as he is color blind in the same way. I have extremely far sighted vision so my son got checked young.

An interview suggestion for you: Sue Barry, an adult woman who regained stereopsis at the age of 48 and wrote an AWESOME book about it called "Fixing My Gaze." She also had some not ideal run-ins with ophthalmologists over it. She's a neuroscientist as well, so she'd be perfect for your interview series.

As an aspiring physician, I love your vids doc! Keep up the phenomenal work!!

I want to see you do a collab with ChubbyEmu and do an episode on those eyedrops.

I worked for a colorblind pathologist about 50 years ago. I don't know his specific diagnosis. He did show us the color filter system he used to convert the various tissue stains to near-monochrome. He was highly respected by the surgical staff, the other pathologists, and the Medical Examiner. And a great guy to work with, even as the junior "computer specialist"

I had a elementary school teacher with complete colorblindness! From what I remember he actually was able to derive certain colors from context (maybe he still had a little bit of cones? But I think he said it was just context).

This might be more of a neurological topic than ophthalmology, but I’d love to hear you discuss cortical blindness. My grandmother developed it and it was very interesting to see what she thought she saw.

Speaking of the iris not healing, I knew that already because my dad has an injury to his iris so there's a little, but noticeable, rip/discolored spot on it that's been there since he was a kid (he may have been born with it). His eye still works just fine though.

I'd love a scary spooky opthalmology or other medical stories themed episode. It just kinda struck me as funny you're talking at 11:30 at night with the lights properly activating every last cone instead of turning them down 😋

Because of one of your videos I bought and now carry with me systane original lubricant PF. Very convenient individual droppers. The other day a colleague mentioned that he felt like he had something in his eye. I offer him one of the droppers to flush it out and he says, ooh, I love systane, thanks. This guy does NOT emote. Most emotionally charged thing he’s ever said to me. Complete resolution of foreign body sensation. Also on the “what is systane PF doing for you” front, had a patient who was complaining of dry eyes - says she uses eye drops constantly. Has been a problem x 10 years, during which she has been to the doctor 0 times. Inspired by aforementioned eyedrop vid, asked more questions about her OTC eyedrops. Dollar store. Suggested that, before we embark on an autoimmune workup, she try preservative free eyedrops. Complete resolution. There is good news out here for eyeballs. In solidarity, Rural FM

Would love to see a video on iridocyclitis. The more detailed the videos the more I enjoy them.

Two of the things about vision really struck me with this episode: 1) The part about cataracts. Very early in my career path toward medicine, I worked at a psychiatric hospital (more like a mental patient warehouse, but that's another story). One of the longer-term patients was a very quiet woman who was there for depression. Why was she depressed? Because she had to have cataract surgery and her glasses were the old-fashioned, truly coke-bottom lensed glasses, and apparently her situation was so very difficult for her to deal with that she refused to ever appear in public again. It was traumatic enough for her that she admitted herself to a psychiatric hospital. Sad, very sad. 2) The main section on Color Blindness. My stepson is Color Blind. What type, I do not know, and if he has been told, he does not recall. His father (deceased) was not Color Blind, nor are his two half brothers (my two sons), nor was anyone else in his father's immediate family or his father's brother or family. I think that is remarkable, like a bolt out of the blue. So it really struck me when you gave the statistic of 7% of the population, and the gene being recessive on the X chromosome. There should be statistically more Color Blind males in this family unless this was not an inherited gene Color Blindness, but a genetic fluke in this one case.

I have green/blue/purple confusion after a head injury. Always wear a helmet when riding a horse!

Thanks this informative episode, doc! I've had colorblindness that has followed me my whole life so it's nice to know just a bit more. I also have an eye condition called intermittent exotropia and I was hoping to learn a bit more about that too! It's a kinda funny condition I love freaking my friends out with since I can just move one of eyeballs at will (albiet only in one direction). Also I hope the teeth curse does not come your way.

This is great content, would be great to learn more about Ophthalmology, Seeing the cool Surgeries, The exams. More of that!!

Thanks Doc! A few weeks ago you said you may bring an eye model form the office so the episodes are even more fun to watch...

So thankful for this series on eyes. On another note - I really appreciated your recent pod with the ortho bros where they talked about the Cranial nerve 6 and its role in strabismus and other things. Would not have connected those two things.

Great topic and explanation! Yes it's a complex topic but your explanation made me feel like I understood what you were talking about. Don't know if I could explain it to someone else without listening to it a few more times but it was done in such a way I would like to listen to it again

Holy Cra.... How is Visine still on the shelves? I tracked down the stories and that's just nuts. Odorless, tasteless, lethal, and available at any grocery or drug store. Wow.

Thanks. Info appreciated.

Huh, so apparently the ophthalmologist equivalent of the general surgeon's adage of "don't f**k with the pancreas" (at least, the general surgeon I shadowed mentioned it, using the exact same phrasing) is "don't f**k with the iris." It's for a completely different reason for the general surgeon (as explained to me, the pancreas has everything in it that can digest what you eat, and since you're made of the same basic stuff that you eat, the pancreas can digest you too if you anger it), but it is interesting that the phrasing is exactly the same, just a different organ/part

There was an even earlier form of cataract surgery done by Galen in Ancient Rome. He’d take a super tiny scalpel, cut a hole in the cornea, then take a tiny straw, and then suck the cloudy lens out.

Turns out that the human body did not evolve with invasive repair in mind. For the vast majority of our existence, anytime a foreign object is untroduced into the body somewhere other than an appropriate orifice, something was going very wrong. The body will try its best to patch and repair things on its own, with mixed success. Maintenence hatches were not in the spec.

Love these eyeball segments Dr G. All the way from Australia 🇦🇺. Learning about eyes at 2am. 😂❤

I absolutely love your videos! 🤩 I wld love some good eyeball news! (Neuromuscular that is) 6th nerve palsy!

Can you talk about pros and cons of LASIK or SMILE

Oooo Can you do an episode on Lasix surgery? Please Dr. G.

Listening to your stream of consciousness is fun, plus I learn things.

One of Viagra's possible side effects is blue tinted vision. How does it do that? Does it somehow boost the blue cones/make them more sensitive?

I had a friend who couldn't see pink/purple at all! He saw it as plain blue. The biggest problem was if he was shopping by himself he would come home with bright purple clothes 😅

My car is tan, people tell me it looks bronze to them. However, I believe it is blue-gray. I tell people that it reflects the sky light. But, maybe its my eyes. And if so, what else am I seeing wrong. Good grief, I was a color photo printer for many years! Perceiving and matching colors was my profession!

Dr. G have you done a podcast on Charles Bonnet syndrome? I have a friend in her late 80s with macular degeneration that suffers horrible hallucinations a lot.

As a mouth opthalmologist, I approve of eye dentists.

Very insightful content

Do one about retinitis pigmentosa !

I helped a best friend realize he has some red green blindness - asked me if I liked his shoes and I said yes but I didn’t think liked that color. We argued over the color. He asked friends and they confirmed the color I saw. He got tested and viola he had some mild color blindness. The topic I would like to see discussed is the quirks of the different eye colors. Do blue eyed people have different eye quirks vs brown vs green? I have heard that blue eyed people have that starburst effect because they let more light in. Is that true?

Just yesterday I was learning about quantization of energy and how quantum jumps model how rods and cones detect different colors, very cool stuff

That hair...dude!😂 I love it🤣❤

For cataract coming back question- do you think the question was referring to PCO? What do you say about PCO to patients before surgery?

Great video

I'd love to hear about diagnosing and treating people that have limited language.

The film /Monster/ definitely lubricated my eyes a whole bunch. (I cried a lot.) It's very good

Could you do a video on YAG laser surgery and Lasik surgeries?

My son is colorblind, I'm the carrier as my dad was colorblind too. I noticed it when my son was young as I knew what to look for. Like my dad, he can't tell blues and purples and greens and browns.

You're hilarious. Keep it up!

Regarding topics, I’d love to hear about blepharitis, or as my (former) doctor called it, my menopausal eyes. I actually have some age causes, some environmental issues (I’m a wood fire potter so am exposed to clay dust, saw dust, and wood ashes,) and some genetic maybe causes like generally fussy eczema and rosacea inclined skin. So I’m interested in structure of… blephars? And causes of inflammation therein. If you’ve covered it already, apologies.

Really enjoying these eye episodes. Just curious if the brain can cause colour blindness by not interpreting the information from the eye?

My dad was red green color blind. Many many decades ago there was a small town in Ohio thatt reversed red and green lights on their only stop light. We were yelling at him from the back seat to stop stop! That's when we learned he was colorblind.

7:57 to quote Sam O'nella, vision went from "I can't tell if i'm dead or not" to "Ah, it's quite yellow out today. OMG, Something moved somewhere!"

Dr Fleck is a Swiftie! this is so cool lol

I know someone with achromatopsia, 100% doesn't see any color. I was internally kind of excited when she said so because of how rare it is to see only gray scale.

I seem to have a touch of color blindness in one eye, is that possible? In my right eye, colors look warmer and more vibrant than the left.

Question: You say the sclera does not heal. Every 2 months I get an IOI of Eylea ... do I end up with just a bunch of holes in my scalera? Is this why they go ape shit with the antibiotics and Betadine which stings like the Dickens.

I have a difficult time distinguishing dark blue from black, even to the point holding two pieces of clothing next to each other and not being able to determine the difference! 😂

I had a boss that thought blue was purple and he couldn't see red. It was fun asking for directions 😂

Any long term complications from lasik? Like will cataracts surgery be more complicated, or any other issues??

I'm red/blue/green color blind and tried the Encroma glasses. They did nothing, they just made everything a little darker and that's it.

How about macular puckering, or retinal thinning for a video?

My father had red-green blindness. My mother found out after they were married. One day, he said he couldn’t find his gray pants. My mother turned the house upside down looking for them. Then my father said, “Here they are!” while holding up a pair of GREEN pants. 🤦‍♀️

Hey Doc, Is there a chance you can do a Knock Knock Eye for an eye exam every non-ophthalmologist medical professional should know? I'm a triage nurse at a community emergency clinic, and it happens often enough that I'll get patients with eye pain, blurred vision, blunt trauma, foreign bodies, and plenty of periorbital cellulitis and conjunctivitis. So while I can figure out eye movement with the H pattern to test the muscles, and can hold up fingers to see how many the patient sees, and I can move my finger towards and away from the patient, I always feel like I'm coming up short. We don't have an ophthalmologist at the clinic, so it's usually either an internist or pediatrician that get cases of infection-related stuff or a surgeon for trauma-related stuff. I kinda feel like this is basic knowledge that has been lost somehow.

You needed to wish back that dentist corneal abrasion

Would you be able to talk about acquired colour blindness some time ? When I was in high school, I had some sort of condition for a period of time where after waking up, for a brief time, I would have colour blindness where all blues became grey, greens and reds became a bit muted. I think this was my blue cones responding to all light. As far as we could guess, it was caused by a pinched nerve. It didn't make sense to me since it would happen no matter my head or neck position, but I was not the doctor so I didn't question. The condition disappeared later on (or at least hasn't re-occurred) and I have since developed BIID as a result of that experience. I wish to go back to having this colour blindness It doesn't seem like one that is documented from what I could find, but it was my honest experience.

That dentist curse is scary, I've had an infect tooth, I wouldn't wish it upon my worst enemy!

What about tetrachromacy? Has that really ever been documented? Is there a test for it other than DNA? Fascinating topic.

Doctor I have a question: What's beyond the eyeball, optic nerve, optic chiasm and occipital lobe? All my anatomy books also show stuff that has nothing to do with eyeballs, therefore I'm confused as to why I have to learn it. (Joke btw).

Holy cow! First like and no views! I'm NEVER this early! I'm so excited!

I feel somewhat over represented in these videos as I have or experienced: colour blindness, lazy eye, retinal detachment, cataract post-vitrectomy and visual snow. I also have recurrent uveitis which I'm not sure has been covered 😀, also scintillating scotoma and suspected glaucoma

Curious how your other docs in your practice like you have such a following on social media. Does it result in patients wanting to only see you? Or does it work against you? I like how Dr Mike is handling being in real practice.

LoL @ cursed by a dentist!

I'm curious to hear some examples for each type of color blindness of colors that get mixed up/mistaken for one another or else significantly altered for each. (I'm about halfway through the episode so I'll edit or delete as appropriate, haha)

There's a book named Island of the Colorblind that's about an island where achromatopsia is common. It's an interesting read.

Oh, I have a good question- how can I remove the "floaters from my eye" ? I'm 30..something, vision ok (with glasses), but I can see some annoying floaters (especially when looking into a microscope.. that doesn't help, hehe).

Sounds like a classic Yiddish curse: May all your teeth fall out, except one to give you a toothache.

Could you please touch on tetrachromacy briefly at some point? It sounds really interesting to me.

As an achromatopsic, I have to remember to tell people my eyes shake normally and I do not have a brain injury. And explaining to judgmental people that just because my pupils are unusual in normal light (bright for me) does not mean I am on drugs. Oh, and I am not snubbing you - I can't see you down the street waving. 🙄

I almost failed kindergarten because no one knew I was actually colorblind. They just thought I was really dumb. Turns out it was a little of both...

Heres my question coming in we'll see if i get an answer. Can a stroke effect color blindness? No one ever knew my grandad was color blind till after the stroke were taking care of him and he says get the screw driver from the red bag. Its a bright green bag though. And we've checked he wasnt misremembering we showed it to him and he thinks its red. I just think him or someone else would of noticed if he was sevearly colorblind a long time ago. Edit googleing it brought up several studies from the NIH so ima say yes it can.

My brother is the only one colour blind in our small family. But something relating to regarding those colour blind glasses, what about video games that have settings for colour blind? How accurate is it?

So if rods which sense light contrast, basically, are your more rough vision and don't produce an image that's quite as sharp as cones, why is it that when trying to pick out details in images it's recommended that you do so in a dark environment like where the vampires in Radiology live? I'm not doubting that it does actually work that way, just curious as to what the mechanism at work is.

You should cover actual blindness in an episode.