Exploding Eye Lecture (Video)

Here is our latest lecture on eye trauma, where I discuss many causes of ocular trauma: heat injury, projectiles (airsoft, paintball, bb gun), chemical burns, laser, and explosive trauma. You can watch this lecture in high-resolution 720p by changing the settings to “HD” in the player below (or by watching the YouTube version in HD mode). This is a graphic presentation … so you might want to watch in full-screen mode for the full effect. Enjoy!

Screen Shots From this Video (comments below)

Eye Fire Damage — The eye is relatively protected from heat and fire damage by its location within the skull.

It also helps that the eye is filled with water (vitreous). Water makes a great conductor of heat, and can dissipate energy. For example, if you hold a balloon over a candle, it will pop immediately. However, if you put water in a balloon and repeat this candle experiment … it will NOT explode. In fact, you can even boil water inside a balloon if you are patient enough.

Disney Smoking Injuries — It’s been about 10 years since I visited Disney World. At the time, it was early in my eye career and I was terrified that tourists (all holding cigarettes at child’s eye height) were going to injure a child by poking their eye with a lit end. Fortunately, cigarettes have a small flame, and the tear surface can immediately quench most of it if the cigarette is only a glancing blow. You prove this by putting out a cigarette on your hand (or even your tongue).

Cigarette to Eye — Applying a lit cigarette to a pig eye, we find surprisingly little burn damage on the surface.

Electronic Cigarette Eye — Electronic cigarettes don’t cause any burn damage to the eye at all!

Sparkler Eye Injury — One injury we see on occasion is a sparkler in the eye. This typically occurs in small children who are given a sparkler to hold on holidays.

Magnesium Eye Damage — Sparklers are dangerous, primarily because the metals they contain (such as magnesium) burn at extremely high temperature. This is a magnesium strip … not only does it burn brightly, but it doesn’t quench well in water.

Sparkler to Eye — The eye’s tear film doesn’t have a chance to quench a magnesium fire, so significant ocular burns can occur.

Ballistic Pendulum — BB guns, airsoft, and paintball are the main penetrating ocular injuries we see with children. In an attempt to estimate the relative damage these “toys” create, we can use a ballistic pendulum. This is a simple plastic block suspended by strings. When shot from the side, the block moves and a scale measures how far it traverses.

BB Gun Energy — We can also calculate the kinetic energy knowing the weight and velocity of the pellets (bbs, paintballs, airsoft pellet). The equation is KINETIC ENERGY = 1/2 x MASS x VELOCITY SQUARED. A BB gun gives about 2 joules.

Airsoft Gun Energy — Airsoft has half the kinetic energy of a steel bb.

Paintball Gun Energy — Paintball, on the other hand, has 15 joules of kinetic energy. That’s about ten times the amount of BB and Airsoft pellet!

Eye Nail — When estimating the damage created by a projectile (bb gun, paintball, airsoft pellet) … the penetrating power of these items must be considered. After all, a single nail can easily pop a balloon with little force. Make that 100 nails, however, and you have a different proposition.

Shoot Tin Can — I then test each of the guns on tin cans and tomatoes to test their penetrating power. Despite its low kinetic energy, the steel bb gun penetrates the best.

Penetration Testing — To to test the penetrating power of these guns, I placed a pig eye in this skull model, and shoot it with each weapon.

BB gun Eye — The BB gun penetrates through the cornea with no problem at all, with extremely gory results.

Airsoft pellet to eye — Airsoft pellets do NOT penetrate through the cornea … even when shot on full automatic.

Paintball to Eye — The paintball completely destroys the eye. Like hitting the eye with a hammer, the globe explodes.

Sulfuric Acid and Sugar Reaction — To demonstrate the damage that acids create on tissue, I perform a simple experiment involving sulfuric acid and sugar.

Exothermic Reaction — Sulfuric acid reacts with sugar to create an exothermic reaction.

Boiling Carbon — As the water boils off, all that is left is a carbon residue.

Eschar — This carbon crust is similar to the crust or “eschar” that forms with acid burns to the eye. Coagulation necrosis and other debris can limit deeper penetration into tissue.

Acid and Base Burn Eye — This is in contrast to bases. Base burns denature proteins, breakdown cell walls, and goes deeper and deeper in the skin and eye.

Acids versus bases — This experiment tests whether acids or bases will cause more tissue damage to the eye. I’ve filled the right glass with 95% sulfuric acid and the left sodium hydroxide (lye).

Dipping eye in acid and base — After dipping these pig eyes in the chemicals, the base causes much more damage … liquefying the tissue and destroying the globe.

Base eye injury — After a few more minutes of base burn, the scleral wall has mostly broken down. You can see the dark uveal tissue (retina, choroid) and the internal lens in the middle.

Acid versus Base — It’s quite obvious here that the base has caused more damage than the acid … the eye on the right has only suffered from surface layer acidic cooking.

This is the Crookes Radiometer. When first invented, it was thought to demonstrate the particle nature of light. Light photons were absorbed by the black panels, and bounced off the white, creating motion. The true mechanism of how this works is more complex, involving the generation of heat along the black panels and air-currents within a partial vacuum. Either way … this radiometer is essentially a “solar mill” and demonstrates that light can transmit energy.

This is a high-powered laser from Dragon Lasers. It has a power of 1000mW (1 Watt). Most laser pointers, in contrast, have a power of only 3-5mW. This laser is therefor about 200 times more powerful.

Laser Balloons — This is evident when shooting at balloons. Here you can see the laser shooting through a line of balloons in only a split-second.

Laser Burn Eye — I can’t demonstrate retinal laser burns in this pig eye (unfortunately, the corneas are too cloudy to transmit light) but we can see that this laser will burn the eye.

M80 Eye — This is a modern m80 firecracker. M-80s were originally created by the military to simulate gun and artillery fire. They caused a lot of injuries and were banned during the 60s. The “modern version” seen in this picture isn’t as powerful … it’s just a regular “firecracker” with a larger housing to make it seem powerful. You know it’s a fake because the fuse/wick also comes out the end (the original m80 had a fuse that came out the side).

Firecracker Eye — During this part of the video, I show the damage of fireworks in an open and closed clay hand.

Firecracker Testing — We then explore the affect of firecrackers near the eye (this is a pig eye from a student dissection kit).

Firecracker Aftermath — Despite the firecracker explosion, the eye hasn’t ruptured.

Eye hand explosion — Enclosing the eye with a hand, creates a more intense explosion.

Bottlerocket Eye — Bottle Rockets can injure the eye from impact and explosive forces.

Ruptured Globe - Limbus — With blunt and concusive trauma, the eye tends to rupture at two places. The most obvious site is at the limbus (at the edge of the cornea). A rupture here is quite obvious, as the uveal tissue (iris) will extrude outward. Repair can be challenging but surgical access is straightforward.

Ruptured Globe - Muscle Insertion — The other location for a rupture is at the insertion of the rectus muscles on the eye. The scleral wall is very thin at these insertion points. These ruptures are much more difficult to get access to, and may even require temporary disinsertion of the muscles during the repair.

Presumed Ruptured Globe — In a case of suspected rupture globe, where the limbus is intact … we may have to explore under the muscles to find the scleral rupture.

28 Comments

Ozone says:

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Hello Dr. Tim Root,

Thanks so very much for yet another explosive video! Very nice one indeed!

Pls kindly post video on BINOCULAR INDIRECT OPHTHALMOSCOPY. This technique NEEDS YOUR EXPERT BREAKDOWN ON VIDEO.

Thanks in advance sir!

preethi says:

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thanks!easy to understand!

othieno ivan says:

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i love u with deep respect sir.
I wish u could come to uganda and be my tutor.
I love u

Anton Vurdaft says:

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Just perfect! You always know, how to amaze your listeners :):) Your efforts are great!

dd says:

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wow

Bill says:

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Fantastic videos as always. Much appreciated. I may not love you as much as Othieno Ivan, but I certainly have great respect for you.

Anant Vikram Lakhotia says:

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Excellent lecture & show Doc. Thanks for enlightening. Very informative and helpful.

Wendy Miller RRT says:

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Wonderful presentation! I look so forward to sharing this with my Diagnostic Medicine Class. Thank you for sharing~

Clive Novis says:

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Excellent. Very ingenious demonstrations.
Thank you very much.
Clive Novis, ophthalmologist, South Africa.

Ms. pink says:

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Excelent lecture!

zhouyingming says:

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thanks，helpful

Daryl says:

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Tnx Dok Timothy. From the Philippines

Prof Rekha Khandelwal says:

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I am teaching in India and love your lectures.I show them to my residents and we all enjoy together.A wonderful way to teach ophthalm ! you have taken so much efforts and it is definitely a unique project.Keep it up.

mohamed says:

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great .. as usual 🙂

many thanks 🙂

ENRIQUE says:

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I am a first year optometry student, and I thoroughly enjoy your videos!

Enrique
Memphis, TN

uzma says:

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awsome lecture i like it to much

khaled thabet says:

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thank you for this very good lecture which contian very important point .

kavya says:

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very useful lecture

Magdy fouad says:

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keep it up doctor, the lectures are awesome, med. students in Egypt like your way of teaching.

Vicky says:

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I train the San Antonio Fire Depertment EMS and was “surfing” for some new material for my burns lecture and found YOU!

This is an amazing and totaly captivating presentation and will most definitely hold the attention of this very unique (easily bored) audience.

You are to be commended for combining scientific data with humor.

wahib says:

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Great job, well done….funny and helpful

SYED BARKAT ISLAM says:

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It’s wonderful and So Impressive

ibe chukwudi T says:

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even as an optometrist, i am greatly instructed by your insightful lectures. keep it up doc.

Ophthoren says:

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Such a awesome video！

Chiranjibi Mainali says:

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awesome doctor
entertaining!!

Dr. Ángel de la Mora says:

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Laser pointers often lack appropriate labeling and They are selling lots of them as toys when the power is far beyond that of pointers (five milliwatts ) so the FDA advises:

– Never aim or shine a laser pointer at anyone.
– Don’t buy laser pointers for your children.
– Before purchasing a laser pointer, make sure it has the following information on the label:
a statement that it complies with Chapter 21 CFR (the Code of Federal Regulations);
the manufacturer or distributor’s name and the date of manufacture;
a warning to avoid exposure to laser radiation; and
the class designation, ranging from Class I to IIIa. Class IIIb and IV products should be used only by individuals with proper training and in applications where there is a legitimate need for these high-powered products.
see more here:
https://www.aao.org/eye-health/news/laser-pointer-eye-injury
http://www.nejm.org/doi/full/10.1056/NEJMc1005818

Cho Cho Lwin says:

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Very nice Video lectures. Thank you.

Omar Chaudhary says:

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Wow, AMAZING lecture!!!! Entertaining and very informative.

28 Comments

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