With this article inaugurated the section of glaucoma. Talk glaucoma in later articles, we will now lay the foundation for understanding how stress can affect eye vision.
What is eye strain?
Ocular pressure is the colloquial name of intraocular pressure, IOP, whose initials are. The eye is a roughly spherical body, but it is solid inside and the covers are too rigid, so to preserve the spherical shape using the same trick that we use to shape a ball or a balloon. We fill the interior of a fluid that is more than atmospheric pressure. If the internal fluid pressure is greater than what is on the outside, the cover is stretched and takes the form (approximate) sphere. The air we filled balloon, and must be under some pressure to maintain the shape and not deform. In the eye goes something like, except that in no air.
Therefore we have inside the eye has a pressure above atmospheric. Recalling the science classes of the school, the pressure is equal to the force between the surface and in the international system is measured in Pascal (Pascal is a Newton/m2 a). However, other measures are more popular, centimeters of water, bar (and its submultiple the millibars), atmospheres, and above all, millimeters of mercury (abbreviated in mmHg). The atmospheric pressure at sea level is usually around 760 millimeters of mercury. This would be the absolute value, but in medicine we measure the pressure relative to atmospheric pressure. When we measure blood pressure and gives us for example 12 / 8, really are 120 mmHg systolic pressure (when it's rush of blood the heart) and 80 mmHg diastolic (when the arteries are more empty of blood). Ie 120 mmHg and 80 mmHg above atmospheric pressure. Note that when we abbreviate blood pressure is very common to remove the zero from the right, it's as if we divide ten the result.
What eye strain values are normal?
The pressure inside the eye is usually around 15 mmHg, but there is much variability, so that it accepts a normal range of 5 mmHg up or down. Ie between 10 and 20 mmHg are considered normal stresses. High intraocular pressure is considered from 21 mmHg, and a low pressure below 6 mmHg. It is very important to understand the variability, patients often do not live this way. It is customary to compare with blood pressure, although they are not comparable. Intraocular pressure rise after another 14 to 16 is not very important (to be honest, none), because a difference of 2 mmHg being rigorous in normal ranges is not significant. An increase in systolic blood pressure ("high") of 14-16 it is significant because a change of 20 mmHg.
Moreover, and this is very important, no intraocular pressure is a constant and unchanging. Fluctuates throughout the day, and change for reasons as seemingly banal as holding your breath or straining with the lid when you measure intraocular pressure. Moreover, the pressure measurement is not accurate, and the best measurement system, including an ophthalmologist and one measures the difference can be of 2 mmHg. Therefore, it is important to several measures of intraocular pressure over Tiemo to make us a better idea.
How do we keep eye strain?
Well, let the numbers and get back to the eye. We have said that a balloon filled with air as to achieve the desired pressure in the interior. But what fills the eye?. It is certainly not air.
The part "noble" of the eye are covered, the internal cavity as such does not have an active role in the formation of the image. Therefore, what fills the eye has two basic functions: a) be transparent to let light through it, and b) maintain intraocular pressure. The two elements that fill the interior of the eye are the aqueous and vitreous humor. The vitreous, vitreous body, or simply vitreous fluid can hardly be called. Constitutes the bulk volume of the eye, and is basically a three-dimensional protein and sugar, with few cells, and have "caught" a good volume of water. No active sanquíneos vessels or nerves. In other words, is primarily a fairly homogeneous tissue that makes support, and that is (mostly) transparent. Just spare suffering, for practical purposes is considered stable, not formed or deleted. Because the vitreous is practically zero dynamics, in order to maintain eye pressure has almost no importance (except in a specific treatment for glaucoma, which is irrelevant now.) Therefore, the head of the intraocular pressure is not necessarily the other element, the aqueous humor. The aqueous humor occupies only the front of the eye from the cornea to the lens. The volume is less important than the vitreous. As its name suggests, the aqueous humor is basically water, filtering the blood forming cells, and it is mostly water, and dissolved in it are various food items, small proteins, oxygen, carbon dioxide, etc. This fluid is not sealed, but to be constantly refilled. It is generated in one part of the eye, circulates among structures, and is absorbed by the other side. This constant movement allows the aqueous humor is always rich in oxygen and nutrients, so that meets the needs of the tissues that have no blood supply, which are the cristalno and the inside of the cornea. The production of aqueous humor is balanced, so that the same amount that is formed, it is extracted. This balance depends on intraocular pressure. We do not know all the details of this balance, but in most cases is very effective. Because the density of the aqueous humor is almost equal to that of water, the pressure inside the aqueous and vitreous is transmitted to the back of the eye. Thus, although the aqueous volume represents a minority, global intraocular pressure conditions.
Aqueous production: the ciliary body.
The aqueous humor is generated in a structure called the ciliary body. I talked about it in this article as an introduction to cataract surgery. It is the natural continuation of the iris (really the uveal portion that lies between the choroid and iris, but not necessary to enter both the anatomy). Within the ciliary body is a muscle, but what concerns us now is the ciliary body parts in contact with the interior of the eye, creating what is called ciliary processes (for those who likes a name, also called pars plicata) . These ciliary processes are the most anterior and internal part of the ciliary body, and are training a "wrinkled" behind the iris, from where the tendons (those "cuerdecita") holding the lens.
How the aqueous humor circulates?
After leaving the ciliary processes, the aqueous is in contact with the lens and the anterior part of the vitreous. A normal vitreous is subject to the retina (and another structure called the pars plana, which now does not matter), so that does not let the watery. But if the vitreous is missing or detached, the watery hole has to go to the back of the eye. Therefore, even though no vitreous (or is detached), well fill the gap left by the aqueous. Therefore, the permanence of the vitreous in the eye is not necessary for vision.
Anyway, it is usual that the aqueous is directed forward. He goes through the space between the lens (especially in front of the anterior capsule) and the iris. Then passes over one of the narrowest sections of the route, which is the edge of the pupil. The pupil is the central hole in the iris, and the edge of this hole is very close to the lens. In fact, it is in contact many times, and only separated during short periods in which the aqueous humor flows. This "narrow passage" will be important in some glaucomatous eyes.
Once saved this step, the aqueous humor enters the anterior chamber (the space between the cornea and iris. Here the aqueous broadcasts from back to front and center to the sides.
Out of the aqueous humor of the eye: Trabeculum and Schlemm's canal
As mentioned before, the water must leave the eye. It does so through existing structures in a very special area, where the cornea meets the iris. This area is called the iridocorneal angle, and is very important. As I explain slowly and drawings, I prefer to leave it for another article, which I now it has become very dense.
Is it bad to have pressure in your eye?
As we have seen, is not bad. In fact it is necessary. Same thing happens with other things in medicine is not bad to have cholesterol, blood pressure or prostate. In fact is (except women who do not have prostate xD). The problem is that the figures for blood pressure or cholesterol are above normal, or that the prostate is enlarged. Cholesterol and blood pressure are necessary for life.
And in the same way, eyestrain is necessary for the functioning of the eye. The problem arises when intraocular pressure is above normal limits. In fact, it is problematic (in fact, is often more problematic) that the intraocular pressure is too low, but this usually happens almost never. When intraocular pressure is high there is greater risk of glaucoma. But beware, not all involve high ocular tension glaucoma, and not all have the high tension glaucoma.
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What is eye strain?
Ocular pressure is the colloquial name of intraocular pressure, IOP, whose initials are. The eye is a roughly spherical body, but it is solid inside and the covers are too rigid, so to preserve the spherical shape using the same trick that we use to shape a ball or a balloon. We fill the interior of a fluid that is more than atmospheric pressure. If the internal fluid pressure is greater than what is on the outside, the cover is stretched and takes the form (approximate) sphere. The air we filled balloon, and must be under some pressure to maintain the shape and not deform. In the eye goes something like, except that in no air.
Therefore we have inside the eye has a pressure above atmospheric. Recalling the science classes of the school, the pressure is equal to the force between the surface and in the international system is measured in Pascal (Pascal is a Newton/m2 a). However, other measures are more popular, centimeters of water, bar (and its submultiple the millibars), atmospheres, and above all, millimeters of mercury (abbreviated in mmHg). The atmospheric pressure at sea level is usually around 760 millimeters of mercury. This would be the absolute value, but in medicine we measure the pressure relative to atmospheric pressure. When we measure blood pressure and gives us for example 12 / 8, really are 120 mmHg systolic pressure (when it's rush of blood the heart) and 80 mmHg diastolic (when the arteries are more empty of blood). Ie 120 mmHg and 80 mmHg above atmospheric pressure. Note that when we abbreviate blood pressure is very common to remove the zero from the right, it's as if we divide ten the result.
What eye strain values are normal?
The pressure inside the eye is usually around 15 mmHg, but there is much variability, so that it accepts a normal range of 5 mmHg up or down. Ie between 10 and 20 mmHg are considered normal stresses. High intraocular pressure is considered from 21 mmHg, and a low pressure below 6 mmHg. It is very important to understand the variability, patients often do not live this way. It is customary to compare with blood pressure, although they are not comparable. Intraocular pressure rise after another 14 to 16 is not very important (to be honest, none), because a difference of 2 mmHg being rigorous in normal ranges is not significant. An increase in systolic blood pressure ("high") of 14-16 it is significant because a change of 20 mmHg.
Moreover, and this is very important, no intraocular pressure is a constant and unchanging. Fluctuates throughout the day, and change for reasons as seemingly banal as holding your breath or straining with the lid when you measure intraocular pressure. Moreover, the pressure measurement is not accurate, and the best measurement system, including an ophthalmologist and one measures the difference can be of 2 mmHg. Therefore, it is important to several measures of intraocular pressure over Tiemo to make us a better idea.
How do we keep eye strain?
Well, let the numbers and get back to the eye. We have said that a balloon filled with air as to achieve the desired pressure in the interior. But what fills the eye?. It is certainly not air.
The part "noble" of the eye are covered, the internal cavity as such does not have an active role in the formation of the image. Therefore, what fills the eye has two basic functions: a) be transparent to let light through it, and b) maintain intraocular pressure. The two elements that fill the interior of the eye are the aqueous and vitreous humor. The vitreous, vitreous body, or simply vitreous fluid can hardly be called. Constitutes the bulk volume of the eye, and is basically a three-dimensional protein and sugar, with few cells, and have "caught" a good volume of water. No active sanquíneos vessels or nerves. In other words, is primarily a fairly homogeneous tissue that makes support, and that is (mostly) transparent. Just spare suffering, for practical purposes is considered stable, not formed or deleted. Because the vitreous is practically zero dynamics, in order to maintain eye pressure has almost no importance (except in a specific treatment for glaucoma, which is irrelevant now.) Therefore, the head of the intraocular pressure is not necessarily the other element, the aqueous humor. The aqueous humor occupies only the front of the eye from the cornea to the lens. The volume is less important than the vitreous. As its name suggests, the aqueous humor is basically water, filtering the blood forming cells, and it is mostly water, and dissolved in it are various food items, small proteins, oxygen, carbon dioxide, etc. This fluid is not sealed, but to be constantly refilled. It is generated in one part of the eye, circulates among structures, and is absorbed by the other side. This constant movement allows the aqueous humor is always rich in oxygen and nutrients, so that meets the needs of the tissues that have no blood supply, which are the cristalno and the inside of the cornea. The production of aqueous humor is balanced, so that the same amount that is formed, it is extracted. This balance depends on intraocular pressure. We do not know all the details of this balance, but in most cases is very effective. Because the density of the aqueous humor is almost equal to that of water, the pressure inside the aqueous and vitreous is transmitted to the back of the eye. Thus, although the aqueous volume represents a minority, global intraocular pressure conditions.
Aqueous production: the ciliary body.
The aqueous humor is generated in a structure called the ciliary body. I talked about it in this article as an introduction to cataract surgery. It is the natural continuation of the iris (really the uveal portion that lies between the choroid and iris, but not necessary to enter both the anatomy). Within the ciliary body is a muscle, but what concerns us now is the ciliary body parts in contact with the interior of the eye, creating what is called ciliary processes (for those who likes a name, also called pars plicata) . These ciliary processes are the most anterior and internal part of the ciliary body, and are training a "wrinkled" behind the iris, from where the tendons (those "cuerdecita") holding the lens.
How the aqueous humor circulates?
After leaving the ciliary processes, the aqueous is in contact with the lens and the anterior part of the vitreous. A normal vitreous is subject to the retina (and another structure called the pars plana, which now does not matter), so that does not let the watery. But if the vitreous is missing or detached, the watery hole has to go to the back of the eye. Therefore, even though no vitreous (or is detached), well fill the gap left by the aqueous. Therefore, the permanence of the vitreous in the eye is not necessary for vision.
Anyway, it is usual that the aqueous is directed forward. He goes through the space between the lens (especially in front of the anterior capsule) and the iris. Then passes over one of the narrowest sections of the route, which is the edge of the pupil. The pupil is the central hole in the iris, and the edge of this hole is very close to the lens. In fact, it is in contact many times, and only separated during short periods in which the aqueous humor flows. This "narrow passage" will be important in some glaucomatous eyes.
Once saved this step, the aqueous humor enters the anterior chamber (the space between the cornea and iris. Here the aqueous broadcasts from back to front and center to the sides.
Out of the aqueous humor of the eye: Trabeculum and Schlemm's canal
As mentioned before, the water must leave the eye. It does so through existing structures in a very special area, where the cornea meets the iris. This area is called the iridocorneal angle, and is very important. As I explain slowly and drawings, I prefer to leave it for another article, which I now it has become very dense.
Is it bad to have pressure in your eye?
As we have seen, is not bad. In fact it is necessary. Same thing happens with other things in medicine is not bad to have cholesterol, blood pressure or prostate. In fact is (except women who do not have prostate xD). The problem is that the figures for blood pressure or cholesterol are above normal, or that the prostate is enlarged. Cholesterol and blood pressure are necessary for life.
And in the same way, eyestrain is necessary for the functioning of the eye. The problem arises when intraocular pressure is above normal limits. In fact, it is problematic (in fact, is often more problematic) that the intraocular pressure is too low, but this usually happens almost never. When intraocular pressure is high there is greater risk of glaucoma. But beware, not all involve high ocular tension glaucoma, and not all have the high tension glaucoma.
The brothers jealousy
Travelling with children
First Aid Accidents
People and food hygiene
First aid: Airway patency
First aid kit
Paracetamol Poisoning
Ibuprofen Poisoning Cause Symptoms Treatment
Aspirin Poisoning Cause Symptoms Treatment
Iron Poisoning Cause Symptoms Diagnosis Treatment
Caustic Poison Cause Symptoms Treatment
Methanol and ethylene glycol poisoning
Hydrocarbon Poisoning Cause Symptoms Treatment
