Eyes of the Submariner: CR4 Challenge (07/15/08)

Could it be because of the red light used to preserve night vision?

Red displays are always awkward to get your eyes to focus on.

John

More likely it has to do with the distance for the eye to focus at for long periods. Most of your focus distance on a submarine is no more than 3 feet! If the eye does not have a chance to refocus at varying distances periodically, the eye will slightly elongate. When the eye remains focused at the same point for a great length of time is gets "stuck" at that focal distance and the lens does not compensate easily because of muscle atrophy.

There have been numerous studies on the subject, which was once thought myopia was hereditary, but ample evidence exists to show that environmental conditions are the main drivers for the development of myopia. For instance, people or groups of people that do not read and do close visual work do not generate myopia at anywhere near the rate that people who are avid readers or study for long periods of time.

However, I do agree that low light conditions can make focus difficult, but most of the crew do not have to work in low light conditions, so there is no need to subject the whole crew to low level red lamps since they don't need the night vision (only a handful ever perform night watch by naked eye).

You are right that the focal length of the eye is different for different colours**. And I suspect that this is the answer that the challenge is seeking. But there is no way that the 6" focal length could be caused in such a way, as the difference in power of the eyes lens is only about 2.2-Dioptres across the entire visible spectrum. Even combined with the 8' far point in the red, that would represent a practical far-point (in the blue) of 15" - and that is while in the submarine. Plus, in the over-fives-and-under-forties, although there will not be complete recovery, the lens and eyeball will only partially 'set' to a temporary far-point. Maybe Tom spent his time of reading lying on his bunk reading, and he could not get far enough away from the wall - but even reading at 8" in red light would not be likely to cause such a large permanent effect if he had other duties that required walking around.
So, if there is truth in such a large long-term effect, it would not be down to the optical environment in the submarine; maybe something in the recirculating atmosphere? or perhaps an indirect consequence of visits to other sorts of red lights when ashore?

**On a slightly related topic: red displays are a real pain for night-driving - particularly for those of us who are slightly long-sighted and suffering from presbyopia, but who don't otherwise need spectacles for night-driving. (Plus, as the lights outside the vehicle are not red, there is no helpful contribution to avoiding night-blindness - provided that the display does not consist only of very bright but small-area sources)

While it sounds good, the red lighting can't be the real reason for the myopia.

"Rig for red" is only used when at periscope depth and only from just before twilight to just after dawn. That happens at most 30 minutes at a time once or twice a day. The remaining 23 hours will be under standard lighting conditions.

Whoa, I must be missing something. I would think rig for red begins at about 30 minutes prior to sunset and continues until dawn. Otherwise, anyone who peeked through the periscope or went topside (like in the olden days of yore), would have night blindness until their eyes adjusted. Plenty of time to miss that fat target or step over the side.

As that corresponds to the Anonymous words, I imagine the Hero was suffering temporary loss of vision, and really meant 12.5 hours per day on average (much longer on sub-Arctic patrols in winter).

No. the sub does not stay at periscope depth all night with the periscope up peeking around. Typically, the sub will perform a night scan once or twice in a 24 hour period. 30 minutes prior to that scan they will rig for red.

So the con is not under those conditions constantly for 12 hours. Also, the rig for red only impacts a small number of the crew, not everyone.

Clarity is all: so "rig for red" is only applied half an hour before it is planned to use the periscope under dark conditions

Correct.

Don't the Deisel subs need to re-charge their batteries at night anymore then??

Or by day, too.

So how do they charge their batteries then? using a snorkel?

Yes, that is one way.

However, the US and British navies only use nuclear subs (they have no active diesel subs). I don't know how long those navies have been exclusively nuclear.

Oh I didn't know we didn't have any deisels left...

You learn something everyday here

well as my grandma used to say ..."if you keep playing with it you'll go blind"

depending on the year tom was serving, a lack of women may be the other reason tom is refering too

so ... possibly a few too many lonely nights

:P

I wonder if the air pressure, or the composition of the air, in a submarine might be a factor. I'm not saying that either one is, I'm just wondering.

Maybe that's why I'm wonderful - I'm always wondering about something.

I can't see how, but I wondered about that. The eye's Vitreous chamber is filled with an aqueous liquid called the vitreous humor. There are actually three chambers, but the Vitreous is by far the largest.

As you know, fluid doesn't compress much and the problem seems to be related to the elongation of the eye between the lens and the retina. So, I can't see how the correlation would cause the effect.

This has to be it!!

------------------------------------

'Live each day like it's your last, because one day, you'll be right.'

English Comedian Benny Hill

That looks a more realistic idea to me - but so far as I know the pressure inside a submarine is maintained at or near normal atmospheric pressure. That leaves the possibility of composition. The following is what I found on this subject - but I'm not qualified to draw any conclusions from it

One known aspect is the concentration of CO₂. I believe that this is typically allowed to vary between 0.01% and 0.5%; levels above 0.3% can be maintained for days at a time. As a reference, the concentration in the lower atmosphere is about 0.03%, and 0.5% is generally regarded as an upper limit for medium-term exposure. Long-term exposure to such levels is likely to cause significant reduction to the ph level of the blood-stream. I have no idea whether this has any significant effect on the optical configuration of the eye . (Short-term effects on breathing are readily observed from concentrations of 1%)
Hydrogen concentrations can also be higher than normal - in the region of 0.2%.
I have not been able to find figures for US vessels, but I understand that the Swedes hold volatile organic contaminants in the sub-ppm region, with only occasional excursions above that, and then only into the sub-10-ppm range. However, one of the prime constituents is benzene.
The Swedes also hold Formaldehyde, NO₂ and Ozone well below accepted safe operational limits.

...I'm told that anyone entering a submarine for the first time finds the atmosphere rather strange, but I'm not clear what constituents are the cause (I think - albeit without any data to support this - that it's unlikely to be the CO₂ in a surfaced vessel) - if indeed the issue is the composition of the air rather than psychological.

P.S. Unless and until someone comes up with a more reasonable explanation, I'm rather tending to the view that a >6-dioptre change in the eye's focus (as required by the challenge) is nothing other than urban (or possibly sub-ocean) myth.

I believe that higher than normal CO2 levels is the most likely answer apart from the lack of focal distance which the question is clearely indicating is not the "other" answer that is being looked for. High levels of CO2 can cause permanent eye degradation of the type described. Since the CO2 is constantly building up in a submarine due to the crew breathing it is usually cleaned up by chemical means using Soda Lime in "scrubbers". This does allow higher than normal CO2 to exist depending on the efficiency of the scrubbers. I am unsure of what the exact levels are and I suspect that modern submarines probably clean up the air a lot better than the older ones used to.

I think it may also be because Tom is an avid reader. Anybody reading a book while out sailing on the ocean must be an avid reader.

Apparently studies in China show an increased percentage of well-educated people having myopia.

Myopia in submariners is attributed to continually looking at fairly nearby objects. Yours eyes adjust to the environment in which they are being used. The average Eskimos who had never been to schools did not have myopia but the first generation of Eskimo kids who went to school had much higher levels of myopia. It has to be the environment. I think what the challenge is asking for is an alternative contributing factor.

Could it be Tom is just getting old?

The effect of aging on the eyes is presbyopia, and that is mainly a loss of elasticity of the lens so it doesn't change focus as fast. It could be possible that the lens loses part of its focal range too. That brings up the question, then, of how submarine service affects aging.

i am a retired submariner joined submarine in 1973 served till 1981 and still my eye site is normal i don't find any meaning in this discussion

crm

My guess is Tom spends too much time on the computer. This might have the same environmental contribution as living in a submarine.

I'm not sure who Tom is but if he is one of the frequent participants in this blog it might be part of the explanation. Before you ask, I was near sighted 25 years before I saw a computer screen.

My first guess is that the quarters on submarines are so close, everything is in such immediate proximity, that the need for the eye to focus at infinity is virtually nonexistent.

Since focusing of the eye to various distances is done by muscular distortion of the organic optics, failure to exercise those muscles in a submarine may have caused a form of muscular atrophy.

If I am correct in this estimate, then it suggests that a well managed exercise program will restore his distance vision.

BTW, as I've understood it, myopia is the name given to those who lack peripheral vision.

Having to hold a book close to read it is something else.

"Here's looking at ya!"(sic!)

I agree with most of the comments here regarding possible causes of myopia (myopic "near-sighted"):

Close work, avid reader, possibility of increased CO2 levels or atmosheric pressure abberations.

A high carbohydrate diet over a number of years has been linked to problems with the eyes including myopia.

But as a possible alternative reason, Tom may have said that the long periods of time spent without any sunshine may have been a contributing factor. It is a Known medical fact that direct sunshine (especially UV) and the vitamin Riboflavin help to strengthen the Sclera (white part of the eye) which would help prevent elongation of the eye; the main cause of myopia.

Here is a paper that highlights all of the current theories for causes of myopia and an alternative theory that ties repiratory function with myopia. By Paul Scanlon (SGTM) posited in 2006. A good read: http://www.i-see.org/scanlan.pdf

I find it impossible to see how the diaphragm can effect the air pressure at the back of the eye. Constricted sinuses might affect the pressure - but SFIK there is no evidence of any correlation between sinusitis and short sight. On the other hand, there is moderate correlation between high blood pressure early in life** and short sight - but >6-dioptres as reported would be grossly beyond the expected range (your arteries would explode first...)

**Although this would tend to elongate the eyeball, I'm not aware of evidence that this is significant.

Hi physicist,

Was away for a couple of days.

The main reason I posted the link was for the discussion of most of the "accepted" causes and fixes for myopia. I don't completely agree with Mr. Scanlan's theory but I can't dismiss it either. If even some of it can be proved, it would fill in a few of the blanks for causes and may lead to more beneficial treatments.

After watching a man squirt streams of milk from his eyes by holding his nose closed, I believe that the sinuses and eyes are in direct contact. Whether or not the respiratory system can exert enough pressure to prevent elongation of the eyeball under normal conditions will require some time, money and acceptable methods of testing.

There seems to be alot of studies into "causes" but there doesn't seem to be a wide acceptance of Any of them to date. I will just await results of further testing into this and other ideas.

Kindest regards,

Jeff

Hi Jeff

Please forgive my displaying prejudice against an apparently over-hyped* theory, with an improbable physical basis and no practical evidence presented; I'm just a humble (?) experimental physicist.
You may also regard it as irrational that my reaction is reinforced by the article being published without time for peer review and in a journal with a new-age name that has a void web-site... or merely curious that I have found no other references to that journal on the web nor copies in my local technical library

*e.g. the author naming it after himself as ".......'s general theory"

Fyz

"After watching a man squirt streams of milk from his eyes by holding his nose closed"

That guy has good lacrimal ducts.

I'll go for reading in bed in very cramped conditions.

I also think it is because Tom is an avid reader, but I also think he strained his eyes in the submarine due to poor light while reading and that the straining of his eyes to make out the letters were the main cause of his Myopia. He did say he had no problems before he was a submariner and he did read before he went to sea.

What is the other explanation Tom is referring to?

Since nobody has come up with verified statistics of any kind, he must be referring to the onset of old age. Since there is no mention of age (only years) He could be just an average person, not a victum of what he did in the past at all.

The idea of relating it to inner eye pressure and the unusual environment of a U-bee seems to be the most appropriate answer. U-bees are a funny mob at the best of times. Once above water (above 40) they seem to get old like the rest of us.

"The Bonfire of the Vanities".

What was he bloody reading that book for? While Fishing stick to your Bates. It could tell you more. Ky.

you are perfectly right as far as i know nun of my submarine batch mates has this problem one of them retired as Chief of Naval Staff who is alive with whom i am still in touch.

crm

Change of vision with old age tends to require you to hold reading material at a further distance since the lens of the eye is no longer as elastic as it once was and it can not focus well at close distances.

Lack of natural light, pressure and reading screens and books to closely.

I vote for the gaseous environmental effects. There is much we do not know about the various effects of chemical interactions in the body as it relates to the environment.

As for the reading too close scenario, if that eye adapted for close vision, then the short vision should improve, not get worse.

I also agree the use of red light is not a factor. If Tom is mid to late mid age, then he would have served in the nuclear navy and the nukes do not surface very often. The nukes stay underwater 99% of the time so that they are less detectable. Even if he served aboard a diesel boat, the red light is only needed while entering and exiting the hatch to the top of the sail.

Age related reduction in focusing capability is more related to the fact that the lens becomes less flexible too.

I think this question has 'got us'...

environmental factors have been discussed, but not agreed.

We've even had an ex-submariner (crm) mention he had no problems with eyesight after 8 years in subs...

So what is the questioner asking for? it may be something that only affects a few submariners such as reading close up in poor light together with time and age...

But after reading the posts on here it seems its got us stumped!!

Anyone know who set this question? I want words with him/her

John.

There are several reasons why Tom is squinting. The first is that he doesn't know what the heck he is doing fishing from a sailboat in the first place. The second is that he's not sure why he's reading Bonfire of the Vanities when the bikini clad bow candy is zipping by on their runabouts. Finally, after drinking enough beer to think that fishing from a sailboat is an interesting passtime Tom would be squint eyed anyway.

I'm with enviro - who comes up with these questions?

Tom is getting old!

I'm sorry, but this challenge question is loaded with 'fail'.

Near-sightedness (myopia) is not caused or worsened by reading or by having always to focus at objects nearby. Presbyopia (far-sightedness) might be worsened since one's distance-vision is not being exercised, but even this seems very unlikely. During a tour of duty a submariner does spend a lot of time using his eyes for close work, but a typical tour of duty may last 6 months at most. The rest of the year he's using his eyes 'normally'.

If Tom was a submariner 'years ago' it's more likely that he would have age-related presbyopia and would hold his book at arm's length to read it. His reading glasses would allow him to hold it at a 'normal' distance.

Also, who invites a friend to go fishing or sailing and then takes a book along? What an entertaining host he is! (Not.) And why a heavy book like TBOTV? He needed some extra ballast?

"Near-sightedness (myopia) is not caused or worsened by reading or by having always to focus at objects nearby."

There seems to be many studies that contradict your claim.

"a typical tour of duty may last 6 months at most. The rest of the year he's using his eyes 'normally'."

This statement would only be true if the submariner got off the sub at the end of his six-month deployment and didn't get back on until his next deployment. Instead, the typical submariner spends over 12 hours per day on the submarine performing maintenance, training and upkeep even while the submarine is in port. Thus, he is subjected to a restricted focal distance for most of his tour on board the sub. It is only when leaves the sub at night and goes home does this artificial restriction get lifted.

ah, true, but the submarine is not under pressue when it is in port and not under water...this is a fluid pressure issue

The inside of the submarine is held near normal atmospheric pressure when under water.

really? since when? have you never seen a submarine shrink? speak of which you know. True, the pressure is 'near' normal or else the human body wouldn't be capable of it, or at least the change...as nitrogen narcosis would become an issue. but there are pressure diffenences and unlike aircraft, submarines tend to maintain them over long periods of time...not hours but months. They also didn't go blind but had minor changes of vision. I don't know what the actuall pressures are, but I do know that your ears pop both submerging and rising....you're telling me that's nothing?

Take a leap, or a ride. Try it...then talk to me. Norad used t run a lot of 'red light' rooms as well as almost all naval ships in CIC prior to the advent of more advanced display options. Yet the same results have not been observed. Empirical evidence then points to someting other than the lights' wavelength.

Try keeping your criticizm to facts instead of something you just thought up.

I've spent months under red light conditions for 12-15 hour per day..for months on end. Never changed glasses or prascripton/

Theorty and priacticd

Actually, for young people the shape of the eyeball is the major factor in causing myopia or presbyopia. Age-related presbyopia is mainly due to the muscles around the lenses losing their ability to change the shape of the lenses to bring objects into focus.

I've worn glasses, to correct my myopia, for a long time. I've never had trouble holding a book at 'reading' distance, with or without my glasses. The idea that his work as a submariner 'years ago' is now causing Tom to hold the book 6 inches from his face to read it is ludicrous. (If that was due to near-sightedness he'd be so blind he'd have to wear glasses all the time, not just once in a while.) As others have pointed out, he might have suffered with temporary myopia when leaving the sub, but after a few hours his vision would have returned to normal. Also, as I and others have pointed out, the changes due to age make a person hold the book further away, not closer than 'normal' reading distance.

Maybe his problem is not myopia or presbyopia, but cataracts?

Presbyopia - not weakness in the muscles - the problem is that the lens becomes less flexible.

Prebyoptic (altogether now...)

what about proper nutrition? ... on long outages at sea improper nutrition could account for loss of sight as well as a few other health problems ...

the old sunken eyes and falling out teeth of scurvy

... or not enough carrots ... there good for your eyes ... right?

I've never eaten better in my life than when on board a submarine. The Culinary Specialists on subs are artisans.

USS Silversides SSN679, 1974 to 1978.

Hell, the lenght of view from foward crew compartment to the mess was ~50 feet. The view from con to the tunnel was ~ 80 feet. Distance was no problem. But the CO2 level was ~2X that of sea level.

I think it is because of age. My eyes are bad also. But then I've been working with and on lasers for 20+ years. That would be more likely. Life and age.

All 688s for me. Longest distance was about 30 feet in the torpedo room; and no one liked to be there.

yes i agree with you the food served on board submarine is the best i ever had both by taste and nutrition is concerned all the more the food is specifically designed by nutrition specialists which you can neither afford nor available for general public.its just a false concept among people the armed forces in general and submariners in particular.doesn't get good food,further the health of the submariners including eyesight is concerned Navies world over takes care of the submariners by conducting routine tests monthly.half yearly and yearly basis and immediate care is taken for any medical issues if any .as the men serving with submarine forces has to meet very high and stringent medical standards so none of the arguments hold any substance as for the eye sight is concerned

crm

Your food alone would be reason enough for me to sign up on an Indian vessel!

Theory is that because of the close up work that in focusing the muscles pull on the ocular sac and this stretches it over time. After a while the fluid fills and the eye become elongated changing the focal point. Test show that the myopia change in submariners is no worst then any other occupation that does close up work.

Not being the hunter/gather that our ancestors were. Those of us with this problem would have be weeded out of the gene pool.

So other explanation Tom may be referring to though is genetics. Have worn glasses most my life for the condition.

My vision wasn't great before I ever set foot on a sub, but it stayed pretty constant until after I got out with 13 years, (and nearly a decade of sea duty on subs). I'm now blind as a bat without my glasses, but I seriously doubt it had anything to do with my service.

- Lighting's not an issue, whether red or white. As others have said, red's only on in the control room, and not continuously even there. In all other spaces except berthing (where the lights are always out), there's more white light fixtures than most office buildings.

- Short focus may be an issue, but there are plenty of passageways on a nuke (even the older ones with more compartments) where the focal length is 15-20 feet or more. Fast boats have less of those areas, and boomers more, but they are routinely used by all personnel on both types.

- Atmospheric composition may be somewhat of an issue, but the continuous air monitoring system on US subs is very precise. While I don't remember the exact values, the alarm points for various gases seemed pretty tight (much tighter than OSHA's confined space requirements).

- Food may also be a factor. Although the surf 'n turf and beef wellington were the best, the lack of fresh fruits and vegetables after the first week at sea may have some effect.

- Another option which has not been discussed has been sudden pressure changes. Although one atmosphere is the norm, a sudden surge or drop in pressure was not uncommon. The surges could be due to weapons testing (firing water slugs) or ventilating. The drops were frequently due to ventilating in heavy seas when the air intake would occasionally submerge.

EMC(ss)

One only sees reflected light. Very little dust in a sub you would see the close equipment and wall of the sub all not too far away.Thje guy may be right. A stronge thing happens in an aircraft at very high altitude, No dust to reflect and your eyes focus at 36 inches the distance to the instrument panel

My first guess would be a lack of fresh carrots [etal.] but that is not really too engineering related. So,

My second guess is artifical environment; distilled water or O3 levels or atmospheric componet ratios, yet these are still predominantly biology issues. So,

My last guess is an abnormally high occurrence of, and the abnormally sudden rate of Atmospheric Pressure Changes causes the eyeball to expand/contract faster than it was designed for and damages either the shape or structural integrity of the eyeball or the controlling musculature. [Caused by diving and surfacing, etc.]

[A statistical inquiry into the lifecycle of pingpong balls aboard subs might show this]

tom

=-==

err, ahh, snowglobes rather than pingpong balls...

tom

=-==

lol, Been a while since I've been a contentios voice on here..but lets give it a try...

Eye...fluid filled orb.

Myopia...nearsightedness or tightening the curvature.

Submarine...Pressure difference...increasing at depth

Timescale..long exposture to the higher pressure coudl have resulted in the eyeball being compressed and resulting in the lens being slightly reshaped as more bent (concave) resulting in a relaxed position that was leaned, not normal.

Do we have alternatives that run with just the proposed facts and do not bring anciliary information in? (and would like to here the anciliory info too)

i suppose its like fixing the cause of carcinoma and cardiac problems and its relation to smoking i have red 100s of research papers that has been published ,but till to day i haven't seen a definite conclusion .At the best we can say smoking is contributory factor and not the cause similarly the working environment in the submarine might be a contributory factor actual cause might be elseware

crm

I noticed a lot of "red light" notice on the eye issues...One thing about submarines....they don't make a lot of use of red light. Red light shortens the wavelength...make the light less visible over distance....since when has that been a concern on submarines?

Unlike the movies you are all stating as fact, lighing on a submarine is brigher and better on the eyes than surface ships as the possibility of another ship or aircraft noticing a light inside a submarine is significantlly lower than seeing the reflection off your sweating forhead as you bob in the middle of the Atlantic or Pacific ocean, becoming shark bait?

Haveing been on both nuclear and diesel subs, as well as frigates, the lighting on submarines is much better.

What about training for rapid emergency decompression, or even, real rapid emergency decompression: especially if Tom suffers from some other condition (such as Marfan syndrome)?

de compression during training would be normally in a training establishment pre planed in real life situation decompression exercise is only during a rare accident like Soviet subs in recent past and USS thresher in April 1963.

crm

I do not believe this is the correct answer. For one thing, the "Old Submariner" did not support the higher pressure theory. Secondly, the contents of the eye are a liquid as well as whatever is behind the eye. There is no more compression to those liquids than to the rest of the body. All parts of the body will receive equal compression effects except the lungs, or any other part of the body that has gas in it. Unless the eyeballs have gas in them, there is no appreciable compression. This cannot be the correct answer.

Yes, I am very skeptical as well for the exact reasons you cited.

Deep-sea divers used to suffer from progressive short sight. For a long time this was assumed to be due to the pressures and subsequent pressure relief, but experience with hyperbaric oxygen treatment has indicated that the myopia is more likely to be a response to high levels of dissolved oxygen in the blood stream during decompression than the pressure of diving.

So: the explanation is not merely wrong in respect of the conditions in a submarine - it is also incorrect in stating that the conditions it assumes would be likely to cause myopia.

Yes, I have a friend that spent his tour as a submariner. I shot him an email with the challenge question and the response, to which he wrote:

"The explanation is 100% total and complete BS. The air pressure in a submarine is controlled at one atmosphere and great care is taken to maintain that pressure. If it were lower than atmosphere, we would need a crane to pull open the hatches, emergency air valves would never work, and the diesel generator would never start against the exhaust pressure. If it were as high as this idiotic story suggests, high enough to reshape the eye permanently, ear drums of every crewman would rupture and the hatches would blow open and explode off the hinges when we do surface."

The real reason is there are no windows on a submarine. By that I mean there is no way to exercise the eye muscles to view objects at distance. Submarines are very 'close' spaces where objects are never further away than at arms reach. Extended time at sea running submerged (over 9 months in some cases) without exercising the eye muscles can lead to atrophy of those muscles and loss of the ability to focus the lens leading to myopic vision."

Did your friend notice the 6"? His explanation surely doesn't cover anything like that extent of short-sightedness.
I still think the question as posed has no valid answer, other than some affliction not directly related to being a submariner (though I suppose that if Tom was claustrophobic the stress might have aggravated the otherwise unrelated condition)

I suspect that Tom is a fictitious character and 6" is just as fictitious.

Really, the debate just drills down to, what are the causes of myopia for crew members of a submarine? There is a high probability that atrophy of the eye is the major contributor and cabin pressure is probably not a factor.