Eye Dictionary: E-F
E
Econopred. This is a steroid eye drop that is commonly used after cataract surgery to cool down ocular inflammation. This medicine contains prednisolone acetate. Prednisolone is also available as a generic ... though there is some debate as to the quality of the generic steroid drop suspensions when compared to the brand names like Econopred and Pred Forte.
ectropion. This is an outward rotation of the lower eyelid, usually associated with laxity of the lower eyelid skin. This rotation causes the eyelid to pull away from the eyeball. This leads to dry eye and tearing problems. Mild cases can be treated with artificial tears and nighttime rewetting ointments. If the ectropion is bad enough, however, it may need to be corrected surgically, usually by tightening the eyelid to reapproximate its normal position. There are many causes of ectropion but the most common cause is simply skin laxity from age. The opposite of an ectropion would be an entropion where the eyelid turns inward such that the eyelashes are rubbing against the eye.
Elestat. A prescription-strength allergy drop containing the antihistamine epinastine. It is useful for treating puffy eyelids and ocular itching. Similar prescription-strength allergy drops include Bepreve, Pataday and Lastacaft.
emmetropia. This describes an eye that is neither nearsighted nor farsighted. An emmetropic eye is perfectly in focus for distance and does not require glasses to see far away.
endophthalmitis. This is an infection that occurs inside the eyeball, usually after an eye surgery or penetrating trauma. Internal ocular infection is dangerous as the eye is essentially a "big ball of water" and can quickly turn into an abscess. The vitreous gel does not have a vigorous immune response so that bacteria can replicate at whim and without tissue in the way to slow down growth. You can compare the eye to a swimming pool ... when a pool starts to turn green, it can go bad very fast as the algae replicates and spreads within the water. Endophthalmitis infection is rare these days thanks to modern surgical methods and prophylactic antibiotic coverage. If we suspect an infection, however, this usually means a trip to see our retinal specialist colleagues for a tap and inject (remove a sample for culture and injection of antibiotics inside the eye). If enough pus forms inside the eye, a surgical vitrectomy may be required to clean it out.
entropion. This is when the eyelids turn inwards such that the eyelashes are rubbing against the surface of the eye. The eyelashes irritate the cornea and can even cause corneal abrasions and scarring. With mild cases we treat with ointments and plucking the lashes. Definitive treatment is surgical with an attempt to rotate the eyelid into a more normal (and comfortable) position. The opposite of entropion would be an ectropion, where the eyelid rotates outward away from the eye.
epiretinal membrane. This is a clear membrane that can form on the surface of the retina and usually occurs with aging (though sometimes after ocular trauma). These membranes are common and can be detected with a dilated eye exam ... they look like a shiny glistening sheen on the retinal surface. While usually innocuous, epiretinal membranes can sometimes cause visual problems from retinal distortion. The retina detects light in the back of the eye. Like film in a camera, the retina surface needs to be perfectly smooth and flat to see well. Epiretinal membranes can contract and constrict, tugging on the retina and making the surface wrinkled. This can seriously affect vision if this distortion occurs at the macula (the part of the retina responsible for our fine central vision). If bad enough, these membranes can even open a hole in the retina (see macular hole). The severity of an epiretinal membrane can be evaluated by tracking vision and scanning the retina with OCT photographs. Monitoring at home can be done with an Amsler grid. Treatment is primarily surgical (though newer injectable medicines are being studied that look promising). A membrane peel surgery can be performed by a retinal specialist. This involves peeling the membrane off the retinal surface, then injecting a gas bubble into the eye to help "smooth" the retina back into its normal configuration. This entity is also called "cellophane maculopathy" or "macular pucker."
epiphora. This is a fancy medical way of saying "watery eyes." There are several causes for epiphora, but oddly enough, watering eyes is usually caused by dry eye. When the eyes are dry, they tend to sting and cause reflexive tearing. Occasionally, epiphora occurs because of nasolacrimal duct obstruction. This is when the tear drainage pathway running to the nose becomes blocked.
erythromycin. A popular and commonly used antibiotic ointment for the eye. This ointment is commonly used for mild to moderate infections and cases of blepharitis (chronic eyelid inflammation). This ointment comes in tubes and is available as an inexpensive generic. This ointment can be rubbed into the eyelashes at night or squeezed into the eye itself as it is an excellent rewetting ointment in its own right.
esophoria. This is a tendency for the eyes to drift inwards (cross eyed). Many people are born with a tendency for the eyes to turn inwards but they build strong eye muscles in youth to offset this. With age, these muscles may weaken and the eyes may turn inwards again, causing intermittent or constant double vision. When the eyes consistently remain misaligned, this is then called an esotropia.
esotropia. This is when the eyes turn inwards (cross-eyed). Ocular alignment problems like this can develop from many sources such as congenital crossed-eyes (which is usually treated with strabismus surgery during childhood to straighten the eyes out). Crossed eyes can also occur from decompensation of a pre-existing esophoria (a natural tendency for the eyes to turn inward). Acute crossing can happen after a stroke or cranial nerve palsy ... new onset diplopia (double vision) needs to be evaluated by an eye doctor.
excimer laser. This is a laser used in LASIK surgery. The laser "beam" produced by this laser has a very short wavelength which is outside of the visible spectrum (so it can't be seen with the human eye). Rather than burning or cutting tissue, this laser produces such intense energy that it actually disrupts molecular bonds and essentially disintegrates tissue. This is useful in LASIK surgery where corneal tissue is ablated (disintegrated) off the surface of the eye and allowed to "blow away in the breeze" ... without causing burns or scars on the clear cornea underneath.
exophoria. This is a tendency for the eyes to drift or turn outwards from each other. If bad enough, this can turn into a true exotropia where the eyes do turn outwards, causing diplopia (double vision).
exotropia. This is when the eyes turn outwards from each other ...and is sometimes described as "wall eyed" (the opposite of cross eyed). This alignment problem can occur for many reasons. Some people have a pre-existing exophoria (a tendency for their eyes to turn outwards) since birth but have built up strong eye muscles to keep their eyes looking straight. Later in life, these muscles can weaken and the eyes can start to drift out and cause intermittent (or constant) diplopia (double vision). Strokes or cranial nerve palsies can also cause an exotropia. Alignment problems like this need to be evaluated by an eye doctor, especially if sudden onset. Treatment is first geared toward finding any underlying cause. Double vision may be treated with prism glasses, eye exercises, or
even strabismus surgery.
extraocular muscles. These are the muscles that control eye movement. Eye muscles insert onto the sides of the eyeball and contract (shorten) to rotate the eye in different directions. Any problem with these extraocular muscles (such as a cranial nerve palsy) can make the eyes go out of alignment and cause double vision (diplopia). With strabismus surgery (surgery to straighten the eyes out) the extraocular muscles can be strengthened or weakened by shortening these muscles orby changing their insertion point on the eyeball. Medical conditions likeGraves' disease and myasthenia gravis can also affect the function of the extraocular muscles and cause double vision.
eye chart. The chart used in an eye doctor's office to measure vision. See Snellen chart.
eyelash. Eyelashes are the small hairs that grow from the eyelid margin that serve to protect the eyes from foreign bodies. The lashes also protect the eye by providing sensory information and activating the blink reflex when touched. Certain glaucoma medications (like latanoprost) can make the eyelashes grow thicker and longer. The medication Latisse can also make lashes longer and is sold specifically for this purpose. Trichiasis is the term used to describe abnormal eyelashes that grow in the wrong direction and rub against the eyeball. People can lose their lashes after chemotherapy and from chronic eyelid inflammation from blepharitis.
eyelid. The eyelid is the mobile tissue that covers the eye, protecting the ocular surface and aiding with lubrication. The eyelids have two distinct layers. The outer layer contains the surface skin and muscles (that function to close the eyes). The inner layer contains the tarsal plate – this is a thick layer with a consistency of cartilage that gives the lid its integrity. Eyelashes run along the lid margin and serve to protect the eye from foreign bodies Also running along the lid margin is a row of excretory pores called the meibomian glands. These glands produce oil which is an important component of the tear film. If these pores clog up, the oil can back up and turn into a chalazion. At the inner margin of the eyelids, near the nose, are two drainage holes called the punctum (see puncta). These punctum drain excess tears into the nose via the nasolacrimal duct. With nasolacrimal duct obstruction, this drainage is blocked and leads to watery eyes. Tears are produced continuously by cells embedded in the eyelid and the surface of the conjunctiva of the eyeball itself. Extra "reflexive tearing" is produced by the lacrimal gland which is located underneath the upper eyelid.
eyelid fasciculation. This is a fancy way of saying "twitching eyelid." Fasciculations are quite common, with people complaining that their whole eye has been twitching and jumping. Upon further discussion, we discover that it is actually their eyelid that has been twitching ... they can both feel it, and often see the skin movement when looking in the mirror. These fasciculations are strange, but almost always harmless and usually caused by minor irritation to the eye. I like to compare eyelid twitching to hiccups. Hiccups usually start when water goes down the "wrong pipe." This creates a sensation that the body needs to cough or retch ... and yet, this body reaction is "overkill." Instead, a funny feedback loop forms between the throat and diaphragm and results in rhythmic hiccups. A similar process may occur with the eye. The ocular surface may be slightly irritated and the eye "thinks" it needs to blink. However, the irritation isn't really that bad, so the eyelid ends up twitching instead. The "eye hiccup" theory is my own, and while not entirely accurate, sums up the underlying process for most people. Most people get their lid twitching in waves, with them occurring off and on for several weeks then nothing for months. Certain stressors like caffeine, weather changes, and diet may set them off. If they are bothersome, I tell my patients to use artificial tears and antihistamine allergy drops. If the twitching involves the rest of the face and mouth (hemifacial spasm), occurs in both eyes at the same time (blepharospasm), or the vision itself "shakes" during the episodes (superior oblique myokymia) ... this is more concerning and you need to be evaluated with an eye exam and possibly a neurologic consult.
eye vitamins. Vitamin supplementation has been found to be beneficial for people with macular degeneration. A large clinical trial called the AREDS Study was sponsored by the National Eye Institute. Its purpose was to look for supplements that might slow the progression of macular degeneration. They found that vitamins A, C, and E (along with the minerals zinc and copper) seemed to have a statistically significant benefit when ingested in high quantities. People with mild and moderate macular degeneration were 25% less likely to progress to advanced disease while on this vitamin cocktail, as compared to people taking a placebo. A follow-up AREDS 2 Study has found more supplements that might help, such as the plant pigments lutein and zeaxanthin. Eye
vitamins are available over-the-counter and come in a slew of names and combinations. The most popular are Ocuvite, PreserVision, and I-Caps.
Eylea. An injectable anti-VEGF medicine used primarily for treating wet macular degeneration. Other drugs with a similar action are the injection drugs Avastin and Lucentis.
ectropion. This is an outward rotation of the lower eyelid, usually associated with laxity of the lower eyelid skin. This rotation causes the eyelid to pull away from the eyeball. This leads to dry eye and tearing problems. Mild cases can be treated with artificial tears and nighttime rewetting ointments. If the ectropion is bad enough, however, it may need to be corrected surgically, usually by tightening the eyelid to reapproximate its normal position. There are many causes of ectropion but the most common cause is simply skin laxity from age. The opposite of an ectropion would be an entropion where the eyelid turns inward such that the eyelashes are rubbing against the eye.
Elestat. A prescription-strength allergy drop containing the antihistamine epinastine. It is useful for treating puffy eyelids and ocular itching. Similar prescription-strength allergy drops include Bepreve, Pataday and Lastacaft.
emmetropia. This describes an eye that is neither nearsighted nor farsighted. An emmetropic eye is perfectly in focus for distance and does not require glasses to see far away.
endophthalmitis. This is an infection that occurs inside the eyeball, usually after an eye surgery or penetrating trauma. Internal ocular infection is dangerous as the eye is essentially a "big ball of water" and can quickly turn into an abscess. The vitreous gel does not have a vigorous immune response so that bacteria can replicate at whim and without tissue in the way to slow down growth. You can compare the eye to a swimming pool ... when a pool starts to turn green, it can go bad very fast as the algae replicates and spreads within the water. Endophthalmitis infection is rare these days thanks to modern surgical methods and prophylactic antibiotic coverage. If we suspect an infection, however, this usually means a trip to see our retinal specialist colleagues for a tap and inject (remove a sample for culture and injection of antibiotics inside the eye). If enough pus forms inside the eye, a surgical vitrectomy may be required to clean it out.
entropion. This is when the eyelids turn inwards such that the eyelashes are rubbing against the surface of the eye. The eyelashes irritate the cornea and can even cause corneal abrasions and scarring. With mild cases we treat with ointments and plucking the lashes. Definitive treatment is surgical with an attempt to rotate the eyelid into a more normal (and comfortable) position. The opposite of entropion would be an ectropion, where the eyelid rotates outward away from the eye.
epiretinal membrane. This is a clear membrane that can form on the surface of the retina and usually occurs with aging (though sometimes after ocular trauma). These membranes are common and can be detected with a dilated eye exam ... they look like a shiny glistening sheen on the retinal surface. While usually innocuous, epiretinal membranes can sometimes cause visual problems from retinal distortion. The retina detects light in the back of the eye. Like film in a camera, the retina surface needs to be perfectly smooth and flat to see well. Epiretinal membranes can contract and constrict, tugging on the retina and making the surface wrinkled. This can seriously affect vision if this distortion occurs at the macula (the part of the retina responsible for our fine central vision). If bad enough, these membranes can even open a hole in the retina (see macular hole). The severity of an epiretinal membrane can be evaluated by tracking vision and scanning the retina with OCT photographs. Monitoring at home can be done with an Amsler grid. Treatment is primarily surgical (though newer injectable medicines are being studied that look promising). A membrane peel surgery can be performed by a retinal specialist. This involves peeling the membrane off the retinal surface, then injecting a gas bubble into the eye to help "smooth" the retina back into its normal configuration. This entity is also called "cellophane maculopathy" or "macular pucker."
epiphora. This is a fancy medical way of saying "watery eyes." There are several causes for epiphora, but oddly enough, watering eyes is usually caused by dry eye. When the eyes are dry, they tend to sting and cause reflexive tearing. Occasionally, epiphora occurs because of nasolacrimal duct obstruction. This is when the tear drainage pathway running to the nose becomes blocked.
erythromycin. A popular and commonly used antibiotic ointment for the eye. This ointment is commonly used for mild to moderate infections and cases of blepharitis (chronic eyelid inflammation). This ointment comes in tubes and is available as an inexpensive generic. This ointment can be rubbed into the eyelashes at night or squeezed into the eye itself as it is an excellent rewetting ointment in its own right.
esophoria. This is a tendency for the eyes to drift inwards (cross eyed). Many people are born with a tendency for the eyes to turn inwards but they build strong eye muscles in youth to offset this. With age, these muscles may weaken and the eyes may turn inwards again, causing intermittent or constant double vision. When the eyes consistently remain misaligned, this is then called an esotropia.
esotropia. This is when the eyes turn inwards (cross-eyed). Ocular alignment problems like this can develop from many sources such as congenital crossed-eyes (which is usually treated with strabismus surgery during childhood to straighten the eyes out). Crossed eyes can also occur from decompensation of a pre-existing esophoria (a natural tendency for the eyes to turn inward). Acute crossing can happen after a stroke or cranial nerve palsy ... new onset diplopia (double vision) needs to be evaluated by an eye doctor.
excimer laser. This is a laser used in LASIK surgery. The laser "beam" produced by this laser has a very short wavelength which is outside of the visible spectrum (so it can't be seen with the human eye). Rather than burning or cutting tissue, this laser produces such intense energy that it actually disrupts molecular bonds and essentially disintegrates tissue. This is useful in LASIK surgery where corneal tissue is ablated (disintegrated) off the surface of the eye and allowed to "blow away in the breeze" ... without causing burns or scars on the clear cornea underneath.
exophoria. This is a tendency for the eyes to drift or turn outwards from each other. If bad enough, this can turn into a true exotropia where the eyes do turn outwards, causing diplopia (double vision).
exotropia. This is when the eyes turn outwards from each other ...and is sometimes described as "wall eyed" (the opposite of cross eyed). This alignment problem can occur for many reasons. Some people have a pre-existing exophoria (a tendency for their eyes to turn outwards) since birth but have built up strong eye muscles to keep their eyes looking straight. Later in life, these muscles can weaken and the eyes can start to drift out and cause intermittent (or constant) diplopia (double vision). Strokes or cranial nerve palsies can also cause an exotropia. Alignment problems like this need to be evaluated by an eye doctor, especially if sudden onset. Treatment is first geared toward finding any underlying cause. Double vision may be treated with prism glasses, eye exercises, or
even strabismus surgery.
extraocular muscles. These are the muscles that control eye movement. Eye muscles insert onto the sides of the eyeball and contract (shorten) to rotate the eye in different directions. Any problem with these extraocular muscles (such as a cranial nerve palsy) can make the eyes go out of alignment and cause double vision (diplopia). With strabismus surgery (surgery to straighten the eyes out) the extraocular muscles can be strengthened or weakened by shortening these muscles orby changing their insertion point on the eyeball. Medical conditions likeGraves' disease and myasthenia gravis can also affect the function of the extraocular muscles and cause double vision.
eye chart. The chart used in an eye doctor's office to measure vision. See Snellen chart.
eyelash. Eyelashes are the small hairs that grow from the eyelid margin that serve to protect the eyes from foreign bodies. The lashes also protect the eye by providing sensory information and activating the blink reflex when touched. Certain glaucoma medications (like latanoprost) can make the eyelashes grow thicker and longer. The medication Latisse can also make lashes longer and is sold specifically for this purpose. Trichiasis is the term used to describe abnormal eyelashes that grow in the wrong direction and rub against the eyeball. People can lose their lashes after chemotherapy and from chronic eyelid inflammation from blepharitis.
eyelid. The eyelid is the mobile tissue that covers the eye, protecting the ocular surface and aiding with lubrication. The eyelids have two distinct layers. The outer layer contains the surface skin and muscles (that function to close the eyes). The inner layer contains the tarsal plate – this is a thick layer with a consistency of cartilage that gives the lid its integrity. Eyelashes run along the lid margin and serve to protect the eye from foreign bodies Also running along the lid margin is a row of excretory pores called the meibomian glands. These glands produce oil which is an important component of the tear film. If these pores clog up, the oil can back up and turn into a chalazion. At the inner margin of the eyelids, near the nose, are two drainage holes called the punctum (see puncta). These punctum drain excess tears into the nose via the nasolacrimal duct. With nasolacrimal duct obstruction, this drainage is blocked and leads to watery eyes. Tears are produced continuously by cells embedded in the eyelid and the surface of the conjunctiva of the eyeball itself. Extra "reflexive tearing" is produced by the lacrimal gland which is located underneath the upper eyelid.
eyelid fasciculation. This is a fancy way of saying "twitching eyelid." Fasciculations are quite common, with people complaining that their whole eye has been twitching and jumping. Upon further discussion, we discover that it is actually their eyelid that has been twitching ... they can both feel it, and often see the skin movement when looking in the mirror. These fasciculations are strange, but almost always harmless and usually caused by minor irritation to the eye. I like to compare eyelid twitching to hiccups. Hiccups usually start when water goes down the "wrong pipe." This creates a sensation that the body needs to cough or retch ... and yet, this body reaction is "overkill." Instead, a funny feedback loop forms between the throat and diaphragm and results in rhythmic hiccups. A similar process may occur with the eye. The ocular surface may be slightly irritated and the eye "thinks" it needs to blink. However, the irritation isn't really that bad, so the eyelid ends up twitching instead. The "eye hiccup" theory is my own, and while not entirely accurate, sums up the underlying process for most people. Most people get their lid twitching in waves, with them occurring off and on for several weeks then nothing for months. Certain stressors like caffeine, weather changes, and diet may set them off. If they are bothersome, I tell my patients to use artificial tears and antihistamine allergy drops. If the twitching involves the rest of the face and mouth (hemifacial spasm), occurs in both eyes at the same time (blepharospasm), or the vision itself "shakes" during the episodes (superior oblique myokymia) ... this is more concerning and you need to be evaluated with an eye exam and possibly a neurologic consult.
eye vitamins. Vitamin supplementation has been found to be beneficial for people with macular degeneration. A large clinical trial called the AREDS Study was sponsored by the National Eye Institute. Its purpose was to look for supplements that might slow the progression of macular degeneration. They found that vitamins A, C, and E (along with the minerals zinc and copper) seemed to have a statistically significant benefit when ingested in high quantities. People with mild and moderate macular degeneration were 25% less likely to progress to advanced disease while on this vitamin cocktail, as compared to people taking a placebo. A follow-up AREDS 2 Study has found more supplements that might help, such as the plant pigments lutein and zeaxanthin. Eye
vitamins are available over-the-counter and come in a slew of names and combinations. The most popular are Ocuvite, PreserVision, and I-Caps.
Eylea. An injectable anti-VEGF medicine used primarily for treating wet macular degeneration. Other drugs with a similar action are the injection drugs Avastin and Lucentis.