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    Thursday, January 04, 2007  

The name "dry eye" can be a little confusing since one of the most common symptoms is excessive watering! It makes more sense, though, when you learn that the eye makes two different types of tears.

The first type, called lubricating tears, is produced slowly and steadily throughout the day. Lubricating tears contain a precise balance of mucous, water, oil, nutrient proteins, and antibodies that nourish and protect the front surface of the eye.

The second type of tear, called a reflex tear, does not have much lubricating value. Reflex tears serve as a kind of emergency response to flood the eye when it is suddenly irritated or injured. Reflex tears might occur when you get something in your eye, when you're cutting onions, when you're around smoke, or when you accidentally scratch your eye. The reflex tears gush out in such large quantities that the tear drainage system can't handle them all and they spill out onto your cheek. Still another cause of reflex tearing is irritation of the eye from lack of lubricating tears. If your eye is not producing enough lubricating tears, you have dry eye.

dry eye

Symptoms of dry eye:

  • Watery eyes
  • The feeling that there's sand in your eyes
  • Eyes that itch and burn
  • Vision that becomes blurred after periods of reading, watching TV, or using a computer
  • Red, irritated eyes that produce a mucus discharge

Causes of dry eye:

  • Age: As we get older, glands in the eyelid produce less oil. Oil keeps tears from evaporating off the eye. Decreased oil production allows tears to evaporate too quickly, leaving the eye too dry.
  • Diseases including diabetes, Sjogren's and Parkinson's
  • Hormonal changes, especially after menopause
  • Prescription medications: These include some high blood pressure medications, antihistamines, diuretics, antidepressants, anti-anxiety pills, sleeping pills and pain medications. Over-the-counter medications including some cold and allergy products, motion sickness remedies, and sleep aids can also cause dry eye.
  • Hot dry or windy conditions: High altitude, air-conditioning and smoke can also cause dry eye.
  • Reading, using a computer or watching TV
  • Contact lenses
  • Eye surgery: Some types of eye surgery, including LASIK can aggravate dry eye.
  • Inflammation: Recent research suggests that dry eye may be caused by inflammation due to an imbalance of "good" fats and "bad" fats.

Diagnosing dry eye:

Your eye doctor can check for dry eye by examining your eyes with magnifying instruments, measuring your rate of tear production and checking the amount of time it takes for tears to evaporate between blinks. The doctor can also check for pinpoint scratches on the front surface of the eye caused by dryness using special, colored eyedrops call fluorescein or Rose Bengal.

Treatments for dry eye:

The most common treatment is use of artificial teardrops that help make up for the lack of natural lubricating tears. Artificial tear products come in liquid form, longer lasting gelform and long-lasting ointment form, which is most often recommended for nighttime use. Many different brands of artificial tears are available over-the-counter. Some contain preservatives and some do not. Unpreserved tears may be recommended for people whose eyes are sensitive to preservatives. Artificial tears can generally be used as often as needed, from a few times per day to every few minutes. You should follow the regimen your doctor recommends.

When infection, inflammation of the eyelids or clogged oil glands contribute to dry eye, special lid cleaning techniques or antibiotics may be recommended. It may also help to avoid hot, dry or windy environments or to humidify the air in your home or office.

Restasis is an exciting new treatment for Dry Eye Disease. Restasis drops help the eyes produce more tears by reducing inflammation, which is often a cause of dry eye. Unlike artificial tears, Restasis is the first drug proven to effectively treat a cause of Dry Eye Disease rather than only temporarily alleviate symptoms.

Punctal occlusion is a medical treatment for dry eye that may enable your eyes to make better and longer use of the few lubricating tears they do produce.a

   [ POSTED BY ALEX @ 6:52 AM ] [ ]


 

During childhood, people with normal vision have the ability to focus on objects as close as their nose and also on objects very far away. They can rapidly, without conscious thought, switch focus from near to far vision. This is called accommodation. As each year passes, that ability to focus and to switch focus decreases. By the time most people reach their forties, they need an aid, such as reading glasses or bifocals, to focus on objects close up. This condition is called presbyopia.

Monovision
Monovision allows a person to see close objects clearly
with one eye and distance objects clearly with the other eye
(Roll your mouse over the image to change it)

Monovision is a technique where one eye (usually the dominant eye) is corrected for clear distance vision, and the other eye is corrected for comfortable near vision. Monovision allows a person to see close objects clearly with one eye and distance objects clearly with the other eye. The vision part of the brain tends to filter out the image from the eye that is not in clear focus, so those who have monovision eventually do not pay attention to the eye that is not as clearly focused. Those who have monovision are often able to see well enough both at distance and near to do things at any age without corrective lenses.

Monovision can be achieved with contact lenses or with vision correction procedures by correcting the non-dominant eye for near vision and the dominant eye for distance vision. If you are considering a vision correction procedure, your doctor can put you into monovision contact lenses so you can try it before you permanently correct your eyes with monovision.

Most people's brains automatically get used to monovision within a couple of weeks or months. In our experience, most people over the age of 40 to 45 who try monovision and take the time to fully become accustomed to it, like it and find it very useful.

   [ POSTED BY ALEX @ 6:50 AM ] [ ]


 

Presbyopia is a vision condition in which the lens loses its flexibility, making it difficult to focus on close objects. During the early and middle years of life, the crystalline lens of the eye has the ability to focus both near and distant images by getting thicker for near objects and thinner for distant objects. When this ability is lost, presbyopia results.

Presbyopia makes it difficult
to focus on close objects

Symptoms of presbyopia:

  • Blurry close vision that starts after age 40
  • Difficulty adjusting focus when switching from near to distance vision
  • Eye fatigue along with headaches when doing close work
Presbyopia
As we age, the lenses in the eyes
lose some of their elasticity
(Roll your mouse over the image to change it)

Causes of presbyopia:

  • Age: As we age, the lenses in the eyes lose some of their elasticity, and without elasticity they lose some of their ability to change focus for different distances. Presbyopia may seem to occur suddenly, but the actual loss of flexibility takes place over a number of years. Long before an individual is aware that seeing close up is becoming more difficult, the lenses in the eyes have begun losing their ability to flatten and thicken. Only when the loss of elasticity impairs vision to a noticeable degree is the change recognized. Presbyopia usually becomes noticeable in the early to mid-forties.

Diagnosing presbyopia:

A comprehensive examination will include testing for presbyopia. Your eye doctor can conduct a refractive evaluation to determine whether your eyes focus light rays exactly on the retina at distance and near. A visual acuity test will determine your ability to see sharply and clearly at all distances. Your eye doctor will also check your eye coordination and muscle control, as well as your eyes' ability to change focus. All of these are important factors in how your eyes see.

Treatment of presbyopia:

Reading glasses and contact lenses are used by many for the temporary treatment of presbyopia. However, there are a number of vision correction procedures that can surgically reduce or eliminate the effects of presbyopia. Some presbyopic patients like monovision, which allows them to see distance clearly in one eye and close-up clearly with the other eye.

   [ POSTED BY ALEX @ 6:49 AM ] [ ]


 

Myopia, unlike normal vision, occurs when the cornea is too curved or the eye is too long. This causes light to focus in front of the retina, resulting in blurry distance vision


Light focuses in front of the retina
causing blurry distance vision
(Roll your mouse over the image to change it)

Myopia is a very common condition that affects nearly 30 percent of the U.S. population. It normally starts to appear between the ages of eight and 12 years old, and almost always before the age of 20. As the body grows, the condition often worsens. It typically stabilizes in adulthood.

Symptoms of myopia:

  • Blurry distance vision

Causes of myopia:

  • Heredity
Object nearby appear clearly

Diagnosing myopia:

Many times, myopia is diagnosed during school screenings. Sometimes parents notice that their children are having difficulty seeing street signs or the television. Your eye doctor can conduct a refractive evaluation to determine whether your eyes focus light rays exactly on the retina at distance and near. A visual acuity test will determine your ability to see sharply and clearly at all distances. Your eye doctor will also check your eye coordination and muscle control, as well as your eyes' ability to change focus. All of these are important factors in how your eyes see.

Treatment of myopia:

Glasses and contact lenses are used by many for the temporary treatment of myopia. However, there are a number of vision correction procedures that can surgically reduce or eliminate myopia.

   [ POSTED BY ALEX @ 6:42 AM ] [ ]


 

The word "Phakic" refers to those who have not undergone cataract surgery and still have their eye's natural internal lens. IOL stands for "intra-ocular lens." In the Phakic IOL procedure, an intra-ocular lens is placed inside the eye. The patient's natural lens is not removed, as it would be in cataract surgery. There are three lens designs under development. The NuVita lens is placed in front of the iris. The Verisyse™, or iris claw lens is attached on the front of the iris. The Implantable Contact Lens, or ICL, is placed between the iris and crystalline lens.


Phakic IOL procedures are being used on severely nearsighted and farsighted patients who may not be candidates for the more common laser procedures such as PRK , LASEK, and LASIK. However, unlike laser vision correction procedures that permanently change your vision, it is possible to remove Phakic IOLs.

 Phakic IOL

Phakic IOLs is for those who:

  • want to reduce or eliminate thir dependence on glasses or contacts
  • are extremely nearsighted or farsighted and not yet presbyopic
  • have had a stable eye prescription for at least one year
  • have no health issues affecting their eyes

What to expect on surgery day:

You will arrive at the surgery center about an hour prior to your procedure. Once you have been checked in you may be offered a sedative to help you relax. You will then be prepared for surgery. The area around your eyes will be cleaned and a sterile drape may be applied around your eye. Powerful eye drops or a local anesthetic will be used to numb your eyes. When your eye is completely numb, an eyelid holder will be placed between your eyelids to keep you from blinking during the procedure.

Next, a very small incision will be made and the intra-ocular lens will be inserted. The small incision will bond itself using the natural outward pressure in your eye, without the need for stitches. The Phakic IOL procedure is very quick, typically taking less than 20 minutes. There also is a short recovery time. The results of the surgery are almost immediate, however your vision will probably be a little blurry from the anesthesia, so someone will need to drive you home. You should relax for the rest of the day. You may experience some discomfort, but this is usually alleviated with an over-the-counter pain reliever. Most patients resume normal activities within a day or two.

   [ POSTED BY ALEX @ 6:40 AM ] [ ]


 

Wavefront technology was originally pioneered in the field of astronomy and physics to aid in reducing 'aberrations' or imperfections in the multiple lenses of telescopes. In much the same way, we use LADARWave® CUSTOMCORNEA® to provide us with an accurate assessment of the optical imperfections found in the entire eye's optical system.

At Laser Eye Center, our surgeons are the first to utilize LADARWavey® CUSTOMCORNEA® wavefront technology to measure and address both lower and higher order aberrations (visual imperfections in the eye's optical system). Unless both lower and higher order aberrations are addressed during laser vision correction, the quality of your vision may not be ideal, even if you have post-operative vision of 20/20.

Here is how this exciting technology works:

Flat light waves enter eye.Flat light waves enter eye.


Distorted light wave exits eye.Distorted light wave exits eye.

First, flat waves of light are passed through your eye using a computerized wavefront measuring instrument called LADARWave®. As the light waves travel through your eye's optical system, the imperfections in the eye distort the flat light waves. LADARWavey® captures the distorted waves as they exit your eye and compares them to the perfectly flat light waves that would have been reflected if your optical system had no distortions.

Higher order abberation.Higher order abberation.


Ideal wavefront map.Ideal wavefront map.

Next, a 3D map is generated representing your unique visual distortions, including both lower and higher order aberrations. This map is then transferred to the LADARVision® 4000 Excimer laser, and guides the laser as it reshapes your cornea, providing you with a truly customized laser vision procedure.


   [ POSTED BY ALEX @ 6:39 AM ] [ ]


 

LADARVision® is unquestionably one of the most sophisticated and precise laser vision correction systems available today.

LADARVision® 4000 Excimer Laser

LADARVision Excimer Laser

Why we've chosen LADARVision®:

  • Using laser and radar technology developed by NASA, LADARVision® was the first approved system with active eye tracking, which compensates for involuntary eye movements. Although other laser systems have now developed eye-tracking systems, LADARVision® has the only system utilizing laser radar tracking technology, a system that measures eye movement 4,000 times each second and is capable of following eye movements regardless of how rapid or erratic they may be. Successful laser application does not rely on your ability to hold your eye perfectly still.


Top left eye without tracking.
Right eye with tracking

With tracker disabled the lines show a high degree of involuntary eye movement.

With tracker enabled, the laser tracks eye movement throughout the procedure.

  • LADARVision® is the only Excimer laser system with an FDA-approved claim that states that its LADARTracker™ improves the accuracy of corneal shaping.
LADARTracker™ improves the
accuracy of corneal shapingl
  • Many doctors believe that the LADARVision® system with its LADARTracker™ is ideal for treating farsightedness and astigmatism because correction for these vision problems requires longer laser treatment times. During these longer treatments, the LADARVision® eye tracker accurately follows eye movement.
  • LADARVision® has the broadest range of approvals of any FDA-approved Excimer laser and makes it the only one capable of treating all types of refractive errors including nearsightedness, farsightedness and astigmatism.
  • LADARVision®'s unique small-spot laser beam (less than one millimeter in diameter) offers micron size reshaping of the cornea resulting in an extremely smooth surface. LADARVision's ability to use a larger optical zone for treatments minimizes potential nighttime side effects of glare, halos, and starbursts. This feature is most important for patients with large pupils.

LADARTracker™ improves the
accuracy of corneal shaping


   [ POSTED BY ALEX @ 6:33 AM ] [ ]


 

LASEK is a relatively new laser vision procedure that combines elements of PRK and LASIK, and may offer some advantages over both. Instead of removing the epithelium (the thin layer of protective skin that covers the cornea) like in PRK, a flap of surface epithelium is loosened with a diluted alcohol solution and moved aside. The surface under the epithelium is then treated with the laser and the epithelial flap is returned to its original position. Using the epithelium flap as a natural protective bandage with LASEK, as opposed to completely removing the epithelium as with PRK, may improve healing and the incidence of postoperative haze.

The margin of safety with LASEK may be greater than that with LASIK as the need for a microkeratome is eliminated, so there's no risk of flap complications.

LASEK removes tissue within the cornea to treat low to high levels of nearsightedness, farsightedness and astigmatism.

PRK

PRK

LASIK

LASIK

LASEK

LASEK

To treat nearsightedness, the steep cornea is made flatter by removing tissue from the center of the cornea. This moves the point of focus from in front of the retina to directly on the retina.

To treat farsightedness, the flat cornea is made steeper by removing tissue outside of the central optical zone of the cornea. This moves the point of focus from behind the retina to directly on the retina.
To treat astigmatism, the cornea is made more spherical -- like a basketball instead of a football. This eliminates multiple focusing points within the eye and creates one point of focus on the retina. Astigmatism can be treated at the same time as nearsightedness and farsightedness.

LASEK is for those who:

  • want to reduce or eliminate thir dependence on glasses or contacts.
  • are at least 18 years of age.
  • have had a stable eye prescription for at least one year.
  • have no health issues affecting their eyes.
  • have wide pupils.
  • have corneas too thin for LASIK.

What to expect on surgery day:

You will arrive at the Laser Eye Center about an hour prior to your procedure. Once you have been checked-in and settled comfortably, you will be prepared for surgery. The area around your eyes will be cleaned and a sterile drape will be applied. You may be given a sedative to help you relax. Eye drops will be used to numb your eyes; no injections or needles are used. When your eye is completely numb, an eyelid holder will be placed between your eyelids to keep you from blinking.

You will arrive at the Laser Eye Center about an hour prior to your procedure

Next, a specially designed instrument will be placed on your eye around the area that will have the laser applied. Then a diluted alcohol solution will be placed in the instrument, which loosens the epithelium from the surface of the cornea. The epithelium is then pushed to the side.

You will be asked to look directly at a target light while the laser reshapes your cornea. The laser will be programmed with the information gathered in your pre-operative exam. The laser treatment will be completed in less than a minute or two, depending on the amount of correction needed. To finish the procedure, your doctor will smooth the flap back into place. A temporary bandage contact lens will be used to keep the epithelium in place and reduce post-operative discomfort.

You will be asked to look directly at a target
light while the laser reshapes your cornea

Following your procedure, your eye(s) may be shielded for protection. Your vision will probably be a little blurry at first, so someone will need to drive you home. You should relax for the rest of the day. You may experience mild to moderate discomfort for two or three days. You will be given instructions on how to manage this discomfort before you leave. Most patients resume normal activities within two to three days. Vision can fluctuate for up to six months.

The laser treatment will be completed
in less than a minute or two


   [ POSTED BY ALEX @ 6:31 AM ] [ ]


 

PRK was the first procedure performed using the Excimer laser. It corrects vision by reshaping the cornea. The difference between LASIK and PRK is that with LASIK a corneal flap is created and the laser is applied to the inner tissue of the cornea. With PRK, the epithelium (or outer skin of the cornea) is removed and a laser is applied to the surface of the cornea. PRK can be used to correct low to high levels of nearsightedness, farsightedness and astigmatism.

PRK
PRK

 LASIK
LASIK

To treat nearsightedness, the steep cornea is made flatter by removing tissue from the center of the cornea. This moves the point of focus from in front of the retina to directly on the retina.

To treat farsightedness, the flat cornea is made steeper by removing tissue outside of the central optical zone of the cornea. This moves the point of focus from behind the retina to directly on the retina.

To treat astigmatism, the cornea is made more spherical -- like a basketball instead of a football. This eliminates multiple focusing points within the eye and creates one point of focus on the retina. Astigmatism can be treated at the same time as nearsightedness and farsightedness.

PRK is for those who:

  • want to reduce or eliminate thir dependence on glasses or contacts
  • are at least 18 years of age
  • have had a stable eye prescription for at least one year
  • have no health issues affecting their eyes
  • have corneas too thin for LASIK
  • have large pupils

What to expect on surgery day:

You will arrive at the Laser Eye Center about an hour prior to your procedure. Once you have been checked in you may be offered a sedative to help you relax. You will then be prepared for surgery. The area around your eyes will be cleaned and a sterile drape may be applied around your eye. Anesthetic eye drops will be used to numb your eyes; no injections or needles will be used. When your eye is completely numb, an eyelid holder will be placed between your eyelids to keep you from blinking during the procedure.

Next, your doctor will remove the epithelium, a thin layer of protective skin that covers the cornea. You will be asked to look directly at a target light while the laser reshapes your cornea. The laser will be programmed with the information gathered in your pre-operative exam. The laser treatment will be completed in less than a minute or two, depending on the amount of correction needed.

Following your procedure, your eye(s) will be examined with a slit lamp microscope. Your eyes may be shielded for protection. Your vision may be blurry or hazy for one to five days. You will experience some discomfort as the epithelium heals and covers the treated area. Eye drops, pain medication and possibly a protective contact lens can be used to minimize this discomfort. Most patients resume normal activities within one to three days. Vision can fluctuate for up to six months.

   [ POSTED BY ALEX @ 6:28 AM ] [ ]


 

Hyperopia, unlike normal vision, occurs when the cornea is too flat in relation to the length of the eye. This causes light to focus at a point beyond the retina, resulting in blurry close vision and occasionally blurry distance vision as well. Usually this condition is undetected until later in life because the young eye is able to compensate for the hyperopia by contracting the internal lens of the eye.

Farsightedness
Light focuses beyond the retina causing
blurry close vision
(Roll your mouse over the image to change it)



Symptoms of hyperopia:

  • Blurry close vision
  • Occasionally, blurry distance vision

Causes of hyperopia:

  • Heredity
Farsightedness (Hyperopia) Objects in the distance appear clearly

Diagnosing hyperopia:

Many people are not diagnosed with hyperopia without a complete eye exam. School screenings typically do not detect this condition because they test only for distance vision. Your eye doctor can conduct a refractive evaluation to determine whether your eyes focus light rays exactly on the retina at distance and near. A visual acuity test will determine your ability to see sharply and clearly at all distances. Your eye doctor will also check your eye coordination and muscle control, as well as your eyes' ability to change focus. All of these are important factors in how your eyes see

Treatment of hyperopia:

Glasses and contact lenses are used by many for the temporary treatment of hyperopia. However, there are a number of vision correction procedures that can surgically reduce or eliminate hyperopia.

   [ POSTED BY ALEX @ 6:00 AM ] [ ]


 

Conductive Keratoplasty is a relatively new procedure that uses radio waves to shrink collagen tissue within the cornea to treat low to moderate farsightedness and presbyopia and bring near vision back in focus.

Using a small probe, thinner than a strand of human hair, a controlled release of radio waves are applied in a circular pattern on the outer cornea to shrink small areas of collagen. This creates a restrictive band, like the tightening of a belt, that increases the curvature of the cornea.

CK NearVision
CK makes the cornea steeper
and increases its focusing power

NearVision CK is for those who:

  • want to reduce or eliminate their dependence on glasses, reading glasses or contacts
  • have difficulty with close vision
  • are at least 40 years of age
  • have not had a significant change in their vision for one year
  • have no health issues affecting their eyes
  • are not pregnant or nursing

What to expect on the day of your procedure:

NearVision CK does not require a surgical facility. First, your eye will be completely numbed with powerful eye drop anesthesia. When your eye is completely numb, an eyelid holder will be placed between your eyelids to keep you from blinking during the procedure. CK_NearVision
Your eye will be completely numbed with powerful eye drop anesthesia

Then either sitting upright as if undergoing an eye exam or lying back, you'll be asked to look at the microscope light. Your eye will be marked with a series of dots. Your surgeon will touch the dots with the probe making a full circle around the outer margins of the cornea. There will be eight to 32 treatment points, depending on the amount of correction needed. As the dots are touched, heat from the radio waves shrinks the tissue, producing a clenching effect that creates a more curved cornea. Some patients elect to have only one eye treated to give them monovision.

CK NearVision
There will be eight to 32 treatment points

Soon after the procedure, your eyes will be examined and you will go home and relax for the rest of the day. For the first couple of days, you may experience some scratchiness in your eyes, or excessive watering. This rapidly improves and medications can be taken to relieve any discomfort. Normal activities are generally resumed within a day or two. While many patients see improvement in their near vision immediately after the procedure, it usually takes a few weeks to several months for vision to stabalize and the results to be fully realized. As with other vision correction procedures, you may experience some discomfort and light sensitivity (glare or halos) for a few days following NearVision CK.

Normal activities are generally
resumed within a day or two

Realistic expectations:

The decision to have NearVision CK is an important one that only you can make. The goal of any refractive surgical procedure is to reduce your dependence on corrective lenses. However, we cannot guarantee you will have the results you desire.

Because NearVision CK is minimally invasive, the procedure has exhibited very minimal risk and almost no side effects. During the first 24 to 48 hours after NearVision CK, you may experience tearing and some discomfort. You may also experience slight over-correction of your vision, which stabalizes during the following weeks. If you are a good candidate, you will be given additional information about the procedure that will allow you to make an informed decision about whether to proceed. Be sure you have all your questions answered to your satisfaction.


   [ POSTED BY ALEX @ 5:59 AM ] [ ]



    Saturday, December 23, 2006  

LASIK - laser vision correction

   [ POSTED BY ALEX @ 11:32 PM ] [ ]