LASIK EYE SURGERY
LASIK is eye surgery that permanently changes the shape of the cornea (the clear covering on the front of the eye). It is done to improve vision and reduce a person’s need for glasses or contact lenses.
For clear vision, the eye’s cornea and lens must bend (refract) light rays properly. This allows images to be focused on the retina. Otherwise, the images will be blurry.
This blurriness is referred to as a “refractive error.” It is caused by a mismatch between the shape of the cornea (curvature) and the length of the eye.
LASIK uses an excimer laser (an ultraviolet laser) to remove a thin layer of corneal tissue. This gives the cornea a new shape so that light rays are focused clearly on the retina. LASIK causes the cornea to be thinner.
LASIK is an outpatient surgical procedure. It will take 10 to 15 minutes to perform for each eye.
The only anesthetic used is eye drops that numb the surface of the eye. The procedure is done when you are awake, but you will get medicine to help you relax. LASIK may be done on one or both eyes during the same session.
To do the procedure, a flap of corneal tissue is created. This flap is then peeled back so that the excimer laser can reshape the corneal tissue underneath. A hinge on the flap prevents it from being completely separated from the cornea.
When LASIK was first done, a special automated knife (a microkeratome) was used to cut the flap. Now, a more common and safer method is to use a different type of laser (femtosecond) to create the corneal flap.
The amount of corneal tissue the laser will remove is calculated ahead of time.
The surgeon will calculate this based on several factors including:
• Your glasses or contact lens prescription
• A wavefront test, which measures how light travels through your eye
• The shape of your cornea surface
Once the reshaping is done, the surgeon replaces and secures the flap. No stitches are needed. The cornea will naturally hold the flap in place.
LASIK is most often done on people who use glasses or contact lenses because of nearsightedness (myopia). It is sometimes used to correct farsightedness. It may also correct astigmatism.
The FDA and American Academy of Ophthalmology have developed guidelines for determining LASIK candidates.
• You should be at least 18 years old (21 in some cases, depending on the laser used). This is because vision may continue to change in people younger than 18. A rare exception is a child with one very nearsighted and one normal eye. Using LASIK to correct a very nearsighted eye may prevent amblyopia (lazy eye).
• Your eyes must be healthy and your prescription stable. If you are nearsighted, you should postpone LASIK until your condition has stabilized.
Nearsightedness may continue to increase in some people until their mid to late 20s.
• Your prescription must be within the range that can be corrected with LASIK.
• You should be in good general health. LASIK may not be recommended for people with diabetes, rheumatoid arthritis, lupus, glaucoma, herpes infections of the eye, or cataracts. You should discuss this with your surgeon.
• Weigh the risks and rewards. If you’re happy wearing contact lenses or glasses, you may not want to have the surgery.
• Make sure you have realistic expectations from the surgery.
For people with presbyopia, LASIK cannot correct vision so that one eye can see at both distance and near. However, LASIK can be done to allow one eye to see near and the other far. This is called “monovision.” If you can adjust to this correction, it may eliminate or reduce your need for reading glasses.
In some instances, surgery on only one eye is required. If your doctor thinks you’re a candidate, ask about the pros and cons.
LASER PHOTOCOAGULATION - eye
Laser photocoagulation is eye surgery using a laser to shrink or destroy abnormal structures in the retina, or to intentionally cause scarring.
Your doctor will perform this surgery at an outpatient or office setting.
Photocoagulation takes place by using the laser to create a microscopic burn in the target tissue.
The laser spots are usually applied in 1 of 3 patterns.
Before the procedure, you will be given eye drops to dilate your pupils. Rarely, you will get a shot of a local anesthetic. The shot may be uncomfortable.
You will be awake and pain-free during the procedure.
• You will be seated with your chin in a chin rest. A special lens will be placed on your eye. The lens contains mirrors that help the doctor aim the laser. You will be instructed to look straight ahead or at a target light with your other eye.
• The doctor will aim the laser at the area of the retina needing treatment. With each pulse of the laser, you will see a flash of light.
Depending on the condition being treated, there may be only a few pulses, or as many as 500.
Diabetes can harm the eyes by causing diabetic retinopathy. It is one of the most common eye diseases that needs laser photocoagulation. It can damage the retina, the back part of your eye. The most severe from of the condition is proliferative diabetic retinopathy, in which abnormal vessels grow on the retina. Over time, these vessels can bleed or cause scarring of the retina.
sIn laser photocoagulation for diabetic retinopathy, laser energy is aimed at certain areas of the retina to prevent abnormal vessels from growing or shrink those that may already be there. Sometimes it is done to make edema fluid in the center of the retina (macula) go away.
This surgery may also be used to treat the following eye problems:
• Retinal tumor
• Macular degeneration, an eye disorder that slowly destroys sharp, central vision
• A tear in the retina
• A blockage of the small veins that carry blood away from the retina
• Retinal detachment, when the retina in the back of the eye separates from the layers below
Cataract removal is surgery to remove a clouded lens (cataract) from the eye. Cataracts are removed to help you see better.
The procedure almost always includes placing an artificial lens (IOL) in the eye.
Cataract surgery is an outpatient procedure. This means you likely do not have to stay overnight at a hospital.
The surgery is performed by an ophthalmologist. This is a medical doctor who specializes in eye diseases and eye surgery.
Adults are usually awake for the procedure. Numbing medicine (local anesthesia) is given using eyedrops or a shot. This blocks pain. You will also get medicine to help you relax. Children usually receive general anesthesia. This is medicine that puts them into a deep sleep so that they are unable to feel pain.
The doctor uses a special microscope to view the eye. A small cut (incision) is made in the eye.
The lens is removed in one of the following ways, depending on the type of cataract:
With this procedure, the doctor uses a tool that produces sound waves to break up the cataract into small pieces. The pieces are then suctioned out. This procedure uses a very small incision.
• Extracapsular extraction:
The doctor uses a small tool to remove the cataract in mostly one piece. This procedure uses a larger incision.
• Laser surgery:
The doctor guides a machine that uses laser energy to make the incisions and soften the cataract. The rest of the surgery is much like phacoemulsification. Using the laser instead of a knife (scalpel) may speed recovery and be more accurate.
After the cataract is removed, a manmade lens, called an intraocular lens (IOL), is usually placed into the eye to restore the focusing power of the old lens (cataract). It helps improve your vision.
The doctor may close the incision with very small stitches. Usually, a self-sealing (sutureless) method is used. If you have stitches, they may need to be removed later.
The surgery lasts less than half an hour. Most times, just one eye is done. If you have cataracts in both eyes, your doctor may suggest waiting at least 1 to 2 weeks between each surgery.
The normal lens of the eye is clear (transparent). As a cataract develops, the lens becomes cloudy. This blocks light from entering your eye. Without enough light, you cannot see as clearly.
Cataracts are painless. They are most often seen in older adults. Sometimes, children are born with them. Cataract surgery is usually done if you cannot see well enough because of cataracts. Cataracts usually do not permanently damage your eye, so you and your eye doctor can decide when surgery is right for you.
RETINAL DETACHMENT REPAIR
Retinal detachment repair is eye surgery to place a retina back into its normal position. The retina is the light-sensitive tissue in the back of the eye. Detachment means that it has pulled away from the layers of tissue around it.
This article describes the repair of rhegmatogenous retinal detachments. These occur due to a hole or tear in the retina.
Most retinal detachment repair operations are urgent. If holes or tears in the retina are found before the retina detaches, the eye doctor can close the holes using a laser. This procedure is most often done in the health care provider’s office
If the retina has just started to detach, a procedure called pneumatic retinopexy may be done to repair it.
• Pneumatic retinopexy (gas bubble placement) is most often an office procedure.
• The eye doctor injects a bubble of gas into the eye.
• You are then positioned so the gas bubble floats up against the hole in the retina and pushes it back into place.
• The doctor will use a laser to permanently seal the hole.
Severe detachments need more advanced surgery.
The following procedures are done in a hospital or outpatient surgery center:
• The scleral buckle method indents the wall of the eye inward so that it meets the hole in the retina. Scleral buckling can be done using numbing medicine while you are awake (local anesthesia) or when you are asleep and pain free (general anesthesia).
• The vitrectomy procedure uses very small devices inside the eye to release tension on the retina.
This allows the retina to move back into its proper position. Most vitrectomies are done with numbing medicine while you are awake.
In complex cases, both procedures may be done at the same time.
Retinal detachments DO NOT get better without treatment. Repair is needed to prevent permanent vision loss.
How quickly the surgery needs to be done depends on the location and extent of the detachment. If possible, the surgery should be done the same day if the detachment has not affected the central vision area (the macula). This can help prevent further detachment of the retina. It also will increase the chance of preserving good vision.
If the macula detaches, it is too late to restore normal vision. Surgery can still be done to prevent total blindness. In these cases, eye doctors can wait a week to 10 days to schedule surgery.
Glaucoma is a group of eye conditions that can damage the optic nerve. This nerve sends the images you see to your brain. Most often, optic nerve damage is caused by increased pressure in the eye. This is called intraocular pressure.
Glaucoma is the second most common cause of blindness in the United States.
There are four major types of glaucoma:
• Open-angle glaucoma
• Angle-closure glaucoma, also called closed-angle glaucoma
• Congenital glaucoma
• Secondary glaucoma
The front part of the eye is filled with a clear fluid called aqueous humor. This fluid is made in an area behind the colored part of the eye (iris). It leaves the eye through channels where the iris and cornea meet. This area is called the anterior chamber angle, or the angle. The cornea is the clear covering on the front of the eye that is in front of the iris, pupil, and angle.
Anything that slows or blocks the flow of this fluid will cause pressure to build up in the eye.
• In open-angle glaucoma, the increase in pressure is often small and slow.
• In closed-angle glaucoma, the increase is often high and sudden.
• Either type can damage the optic nerve.
Open-angle glaucoma is the most common type of glaucoma.
• The cause is unknown. The increase in eye pressure happens slowly over time. You cannot feel it.
• The increased pressure pushes on the optic nerve. Damage to the optic nerve causes blind spots in your vision.
• Open-angle glaucoma tends to run in families. Your risk is higher if you have a parent or grandparent with open-angle glaucoma. People of African descent are also at higher risk for this disease.
Closed-angle glaucoma occurs when the fluid is suddenly blocked and cannot flow out of the eye. This causes a quick, severe rise in eye pressure.
• Dilating eye drops and certain medicines may trigger an acute glaucoma attack.
• Closed-angle glaucoma is an emergency.
• If you have had acute glaucoma in one eye, you are at risk for it in the second eye.
Your health care provider is likely to treat your second eye to prevent a first attack in that eye.
Secondary glaucoma occurs due to a known cause. Both open- and closed-angle glaucoma can be secondary when caused by something known.
• Medicines such as corticosteroids
• Eye diseases, such as uveitis (an inflammation of the middle layer of the eye)
• Diseases such as diabetes
• Eye injury
Congenital glaucoma occurs in babies.
• It often runs in families.
• It is present at birth.
• It is caused when the eye does not develop normally.
Strabismus is a disorder in which both eyes do not line up in the same direction. Therefore, they do not look at the same object at the same time. The most common form of strabismus is known as “crossed eyes.”
Six different muscles surround each eye and work “as a team.” This allows both eyes to focus on the same object.
In someone with strabismus, these muscles do not work together. As a result, one eye looks at one object, while the other eye turns in a different direction and looks at another object.
When this occurs, two different images are sent to the brain — one from each eye. This confuses the brain. In children, the brain may learn to ignore (suppress) the image from the weaker eye.
If the strabismus is not treated, the eye that the brain ignores will never see well. This loss of vision is called amblyopia. Another name for amblyopia is “lazy eye.” Sometimes lazy eye is present first, and it causes strabismus.
In most children with strabismus, the cause is unknown. In more than one half of these cases, the problem is present at or shortly after birth.
This is called congenital strabismus.
Most of the time, the problem has to do with muscle control, and not with muscle strength.
Other disorders associated with strabismus in children include:
• Apert syndrome
• Cerebral palsy
• Congenital rubella
• Hemangioma near the eye during infancy
• Incontinentia pigmenti syndrome
• Noonan syndrome
• Prader-Willi syndrome
• Retinopathy of prematurity
• Traumatic brain injury
• Trisomy 18
Strabismus that develops in adults can be caused by:
• Diabetes (causes a condition known as acquired paralytic strabismus)
• Graves disease
• Guillain-Barré syndrome
• Injury to the eye
• Shellfish poisoning
• Traumatic brain injury
• Vision loss from any eye disease or injury
A family history of strabismus is a risk factor. Farsightedness may be a contributing factor, often in children. Any other disease that causes vision loss may also cause strabismus.
Dacryocystitis is infection of the tear (lacrimal) sac usually due to a blockage in the tear (nasolacrimal) duct. The tear sac is a small chamber into which tears drain. The usual cause of dacryocystitis is a blockage of the nasolacrimal duct, which leads from the tear sac into the nose. Dacryocystitis may occur suddenly (acute) or be longstanding (chronic).
Often the dacryocystitis infection is mild. Sometimes, the infection is severe and can cause fever. Sometimes a collection of pus (abscess) may form, which can rupture through the skin, creating a passage for drainage.
In acute dacryocystitis, the area around the tear sac is painful, red, and swollen. The area around the eye may become red and watery and may ooze pus. Slight pressure applied to the tear sac may push thick material through the punctum (the opening at the inner corner of the eyelid near the nose).
Chronic dacryocystitis causes the skin over the small chamber into which tears drain (tear sac) to bulge. When pressure is applied, the bulge may not be painful, but a puslike or cheeselike material often comes out of the opening at the inner corner of the eyelid near the nose (punctum or tear duct). People with chronic dacryocystitis often also have chronic conjunctivitis (pink eye).
Diagnosis of Dacryocystitis
• Symptoms and a doctor’s examination
A doctor bases the diagnosis of dacryocystitis on the symptoms and examination findings.
• For acute dacryocystitis, antibiotics followed by surgery
• For chronic dacryocystitis, surgery
Acute dacryocystitis is usually treated with an antibiotic taken by mouth. If a fever is present or if the infection is severe, antibiotics given by vein may be required. Applying warm compresses to the area several times a day also helps. After the acute infection resolves, doctors recommend that people have surgery to bypass the blockage (dacryocystorhinostomy [DCR]) so that infection does not recur. DCR is also the main treatment for chronic dacryocystitis.
IOL IMPLANTS: Lens Replacement After Cataracts
An intraocular lens (or IOL) is a tiny, artificial lens for the eye. It replaces the eye’s natural lens that is removed during cataract surgery.
The lens bends (refracts) light rays that enter the eye, helping you to see. Your lens should be clear. But if you have a cataract, your lens has become cloudy. Things look blurry, hazy or less colorful with a cataract.
Cataract surgery removes this cloudy lens and replaces it with a clear IOL to improve your vision.
IOLs come in different focusing powers, just like prescription eyeglasses or contact lenses. Your ophthalmologist will measure the length of your eye and the curve of your cornea. These measurements are used to set your IOLs focusing power.
What are IOLs made of?
Most IOLs are made of silicone, acrylic, or other plastic compositions.
They are also coated with a special material to help protect your eyes from the sun’s harmful ultraviolet (UV) rays.
The most common type of lens used with cataract surgery is called a monofocal IOL. It has one focusing distance.
It is set to focus for up close, medium range or distance vision. Most people have them set for clear distance vision.
Then they wear eyeglasses for reading or close work
A chalazion is a small bump in the eyelid caused by a blockage of a tiny oil gland.
A chalazion is caused by a blocked duct in one of the meibomian glands. These glands are located in the eyelid directly behind the eyelashes. They produce a thin, oily fluid that lubricates the eye.
An eyelid twitch is a general term for spasms of the eyelid muscles. These spasms happen without your control. The eyelid may repeatedly close (or nearly close) and reopen. This article discusses eyelid twitches in general.
The most common things that make the muscle in your eyelid twitch are fatigue, stress, caffeine, and excessive alcohol intake. Rarely, they can be a side effect of a medicine used for migraine headaches.
Once spasms begin, they may continue off and on for a few days. Then, they disappear. Most people have this type of eyelid twitch once in a while and find it very annoying. In most cases, you won’t even notice when the twitch has stopped.
You may have more severe contractions, where the eyelid completely closes. This form of eyelid twitching is called blepharospasm. It lasts much longer than the more common type of eyelid twitch. It is often very uncomfortable and may cause your eyelids to close completely.
Twitching can be caused by irritation of the:
• Surface of the eye (cornea)
• Membranes lining the eyelids (conjunctiva)
Sometimes, the reason your eyelid is twitching cannot be found.