The epithelium doesn’t attach to the cornea after an injury.  It is loose and easily torn off.  Normally the epithelium should attach back to the cornea.  When this part of the eye is injured as from a scratch, an abrasion or a foreign body, the epithelium should grow back, seal down to the cornea and heal in a quick manner.  The epithelium of the cornea is one of the quickest healing tissues of the body in fact.  The presumably healed epithelium may cover the injury site and even appear normal  even with a microscopic view.

This condition is considered a dystrophy which means the tissue doesn’t work the way it should.  In this case, it doesn’t heal properly.

This can be a very frustrating condition for patients to endure.  They will report a sensation that a foreign body must still be present even though it was completely removed earlier.  This feeling of pain can be quite intense.  Extreme sensitivity to bright light can occur also when this problem is at it’s worst.  The patient swears something is still there and will even doubt that the doctor got the foreign body out – suspecting that another must be present or that the doctor must have missed something.

What is happening is that the epithelium moves with each blink.  The blink moves the loose epithelium, healed but not attached over the cornea. The epithelium rubs against raw nerve endings giving the sensation of a persistent foreign body with each blink.  Doubt about the health care provider’s competency may enter the patient’s mind especially if previous foreign bodies never produced such a problem.  ”This used to always get better,” or “I’ve had these injuries before and they healed up quite quickly in the past,” are common statements made by some.

Patients with Recurrent Corneal Erosion may often seek several opinions for their condition if they feel their current doctor does not appear to be efficiently healing their problem.  They can move from doctor to doctor in frustration.

RCE can be difficult to treat because it recurs.  A patient may carefully follow the correct treatment and suddenly lose all their success upon awakening one morning in pain – the epithelium rubbed off because of dryness of the eye causing the upper lid to adhere to the epithelium, ripping it when the eyes are first opened upon awakening.  The can occur over weeks – even months.

We find that the treatment needs to be customized to each patient.  A strategy for one patient may not necessarily work for another.  The treatments we try include:

Artificial tears: Many times a day.  Usually more is needed than the patient can attend.  One drop even once an hour or more often may be necessary.

Nighttime Ointment:  A bland ophthalmic ointment such as Lacrilube or Refresh PM instilled into the eye helps to prevent nighttime drying – which may be the most common reason for recurrence.

Hypertonic saline solution such as Muro 128 5% by Bausch and Lomb is a salt water drop that is 5 times more salty than our natural tears.  The extra salt of these drops can draw fluid trapped between the epithelium and the cornea to help the epithelium adhere to the cornea.  This drop may be needed several times a day and can sting upon instilling.  An hypertonic ointment at night may also be prescribed.

Bandage contact lenses may help by fitting tight against the cornea preventing the epithelium from moving.  This can allow the epithelium to stay still long enough to adhere.  For some people, a bandage contact lens may not work or seem to worsen the condition.  Studies have demonstrated that snug to tight fittting lenses can work best.  However a dry eye condition itself can make a lens uncomfortable.

Patching of the eye can be used if a bandage contact lens does not work.  Patching for some people  however may feel worse in a way similar that the bandage contact lens didn’t work.

Debridement is a procedure that removes the loosened epithelium.  A very light scuffing of the cornea may roughen the surface enough to allow the epithelium to grow back attached to the eye.

Anterior stromal puncture accompanied with debridement places a grid of tiny anchor points for the epithelium to attach to the cornea as it grows back.

Ocular comfort drops is a recent development.  A formulation of dilute anesthetic was recently discussed at an ocular disease conference.  Only 10% the strength of normal anesthetic, it’s weak enough to prevent toxic effects but allow patient comfort until healed.  This requires careful follow up to prevent complications and can only be used for a very select few conditions.  We have had excellent results with this option.

Time is a critical component of any treatment of this condition.  Days may run into weeks which run into months.  Setbacks may occur frequently requiring we begin from the beginning all over again.  The good news is that most patients do get the upper hand in successfully managing this condition and achieving a complete healing – although it took longer than they wish.

If you suffer from this condition you have our sincere empathy and understanding.  Persistence on your part will pay off in overcoming this often painful and nagging healing problem.  We dedicate ourselves to staying with you during thick and thin in helping you achieve a normal life.

This type of strabismus is called a left intermittent hypertropia.  There is a deviation of the left eye upward.

Most images show Lincoln’s eyes pointing straight which suggest the problem was not constant.

The image above is probably amongst the most well known of Lincoln portraits and also one which shows the problem.  His left eye is deviating upward slightly revealing more of the white part of his eye (the sclera) than in his right eye which is looking into the camera.

Another image illustrates the problem – perhaps more so.

Most other portraits of Lincoln show a head tilt to the right which could be a compensation for the relative weakness of an extraocular muscle producing the deviation.

Finally, what if one applied colorizing technology to Lincoln’s portrait?  You may come up with this result.  Coloring of an image taken by Alexander Gardner on February 5, 1865 and colorized by James Nance for the Abraham Lincoln Art Gallery.

His head tilts to his right slightly.  What impact does this image bring to you by adding color?

Cataract Surgery is Done with Lasers
Never – almost. Yes, experimental research but nothing practical yet developed. Nearly 100% of cataract surgeries are still performed with traditional microsurgical techniques. Lasers can be used after cataract surgery to clear up cloudy membranes. This is where the confusion may often lie.

All Red Eyes are Infections
It has been our experience in our office that most red eyes are due to allergies or dry eye.We see more viral than bacterial etiological causes. This is why your eye doctor can’t just call in some antibiotic. Antibiotics fight bacteria and do not kill viri or decrease allergies.

Refractive Surgery Forever Removes the Need for Eyeglasses
People may assume no more visits are required to the eye doctor after refractive surgery. In fact people need MORE FREQUENT eye care after eye surgery. Refractive surgery today has a better than ever chance of eliminating your refractive error. One condition it can not cure however is Presbyopia. Presbyopia is the natural loss of focusing ability which first shows symptoms past the age of 40. Increasing working distance, eyestrain, blurred near vision are its symptoms. Presbyopia is not treatable except for corrective lenses.

Contact Lenses can be Welded to the Eye if you Weld with Them In
Nope. Contact lenses actually have been found to protect the eye from severe injury. Less trauma has been observed following foreign bodies and chemical splash/burns to the eye. A contact lens has been found to act as a protective shield for the cornea often taking the brunt of damage.

Stronger Glasses can Fix Every Vision Problem
“All I need is a pair of glasses that will work.” is a complaint often heard by eye doctors from patients seeking second opinions due to eye and vision conditions which have deteriorated their ability to see. Neurological problems can interfere with vision. Post-concussion syndrome frequently complicates vision problems. Cataracts interfere with a person’s ability to see. Retinal diseases like macular degeneration often cause a desire for a patient to ask the doctor for stronger glasses. Sometimes they are prescribed, but often special low vision magnifiers, electronic magnification aids and other special aids are needed.

Poor Night Vision is Infrequent
This is actually our most common complaint that we hear of. Small refractive errors is #1 cause. At night the pupil dilates which causes the eye to become more sensitive to changes in an eyewear prescription. Cataracts, macular degeneration, optic nerve disease and contact lens overwear can decrease night vision as well. Nicotine has been shown to decrease the ability to dark adapt. Dirty car windshields can create a phenonema known as the Mandelbaum effect. The focusing system draws inward creating an artificial form of near-sightedness. Night myopia is a similar phenonema which can occur as well despite perfectly clear windshields. Rainy weather decreases your ability to see to drive at night. Wet roads decrease the amount of light reflected back to you from your headlights and increase the amount of light from oncoming cars. Often no detectable problems are found. Aging is a frequent cause of night vision problems. The retina takes longer to recharge its photoreceptor chemicals as we mature. Retintitis Pigmentosa, a traditional cause of night blindness is another retinal disorder which has classically been associated with poor night vision is actually very uncommon.

Eyeballs are Removed During Surgery
Rarely, surgeons usually work around them. The muscles and the optic nerve are of a fixed length. Removing the eye risks avulsing (tearing) of the optic nerve.

“I’m Legally Blind Without my Glasses”
By it’s definition legal blindness is 20/200 in the better eye with correction (glasses or contact lenses) or less than a 20 degree visual field in the better eye. To say you are legally blind without glasses is not in keeping with the true definition.

These Lenses are Scratch-Proof
No lens yet developed is truly scratch-proof. There is always some material which can scratch a lens. A diamond can be scratched by another diamond. Lenses instead should be termed scratch-resistant. A plastic lens with a scratch-resistant lens is more durable than a lens without the coating. Glass to this date remains the most scratch-resistant material – more durable than plastic with a scratch-resistant coating.

Migraine

Some authorities have stated that up to one quarter of the population experience a migraine headache at some time in their life.  It is a disease which usually starts in childhood, and peaks in the third and fourth decades, only to subside in many patients as they enter their fifties.  Most but not all patients have a history of migraine in other family members.

Classic migraines can produce visual phenonema which include "fortification spectra" with a blurred vision zone surrounded by zig-zag type lines resembling an 1800's era fort.

Although the cause of migraine headaches is not known, the mechanism of pain and other symptoms seems to be related to exaggerated fluctuations in the size of the blood vessels to the brain and its surrounding structures.  These contractions and relaxations of the muscles in the blood vessels may be due to abnormal concentrations of certain chemicals such as histamine, serotonin, and prostaglandins.  In the classical episode, a period of narrowing causes decreased blood flow, followed by the dilating phase in which the onrushing blood stretches the pain sensitive lining tissues.

Symptoms

The typical case begins with a warning phase in which the patient has an “aura” of impending problems.  There may be flashing lights in one eye, blurring, blind spots, or distortions of vision.  Distortions may take the appearance of zig-zag lines.  These are called “fortification spectra” — so named because of the similarity in appearance of the design of military forts 100 years ago.  Tingling of the arms or face may occur. After about thirty to sixty minutes, the headache begins: usually on one side but sometimes becoming generalized, it is pounding, worse with movement or bending over, and can be excruciating.  Nausea and vomiting may follow, with marked sensitivity to bright lights and loud noises.  The sufferer may want to withdraw to a dark quiet room, yet the headache seems to follow him everywhere. Usually within 4 to 6 hours, it finally subsides.

The above description concerns a classic migraine; many or even most patients have variations on this theme.  The more common “common migraine” may lack the warning symptoms, and the headache may be far longer lasting, although similar in nature. Irritability and depression may occur hours or days before the onset. Still other patients may have combinations or alternating episodes of headaches with exceptions to the above descriptions or other unusual symptoms including periods of paralysis, dizziness, or even loss of consciousness.

Precipitating factors are multiple–commonly mentioned examples include stress, sleep recovery after a period of deprivation (“Sunday morning headache”), fasting, alcohol in general and red wine in particular, menstruation, and caffeine excess or withdrawal. Birth control pills may cause or worsen migraines, and may be a risk factor for strokes.  More women than men suffer with migraines, but not to an extreme degree.

DIAGNOSIS

Although the history is often virtually diagnostic, the careful physician will be alert to clues suggesting the presence of an alternative or additional diagnosis including tumors, hemorrhage, infection, or other disorders.

If there is any doubt, further tests of the blood, x-rays, and other neurologic evaluations may be necessary.

Treatment
Once the diagnosis is firm, obvious causes eliminated, and the patient reassured about the nature of the disorder, appropriate counseling is given to deal with any stress or other psychological elements at play. Medications may then play a major role in management.

Ergotamine and related drugs such as Cafergot, Ergomar, and Midrin contain blood vessel constricting agents.  They are generally given by mouth, but some may be given by rectal suppository if vomiting is present.  When given early, especially in the warning stage, they may successfully abort the headache within seconds to minutes.  Repeated bouts of headaches may be prevented with weeks to months of prophylactic doses of similar drugs.  Side effects include severe blood vessel obstruction, angina, and other symptoms, but are uncommon at the usual doses. These are potent drugs and should be taken under close supervision and only in the prescribed doses.

Sometimes the ergot class of drugs are not successful.  In the acute case, pain relievers including narcotics may occasionally be needed.  Other drugs including methysergide and cyproheptadine are occasionally used.  Propranolol and amitryptilline are two of the most commonly used preventive drugs, and are useful when headaches are occurring with sufficient frequency to interfere with productive daily activities, or when excessive doses of ergots are required.  A promising new development is the discovery that a class of drugs called “calcium channel blockers” can dramatically treat even the most resistant cases at times, and possibly may have a preventive role as well. Nifedipine is such a drug. Still experimental for this disease (although in wide use for certain heart conditions), calcium channel blockers may have a vital role in migraine therapy of the near future.

Cluster Headaches
Somewhat similar to common migraines, cluster headaches differ in their tendency to occur over several weeks or months in rapid sequence–daily or several times weekly, then disappearing for months at a time, i.e. clusters of headaches.  Typically, they strike young adult males, often awakening the sufferer at night, confined to one side of the face or head, and often accompanied by tearing or nasal discharge. The pain may be the most severe ever experience, and victims have been said to commit suicide to escape the pain.  Thankfully they are usually self-limited and disappear after an hour or so.

Therapy has traditionally been similar to that of migraine, although a preventive emphasis is often more prominent. Calcium blockers, as discussed above, may revolutionize therapy as their role becomes better established. Lithium, prednisone, and indomethacin have also been useful at times.

Tension Headaches
The commonest of headaches, tension headaches are caused by the involuntary sustained contraction of the muscles surrounding the skull and face. Prolonged mental concentration, stress, and a variety of individual factors may bring on the pain.  Young people are affected most often, though the headaches may persist for life.  Almost no one escapes at least an occasional tension headache.

Common pain patterns are those involving the back of the head and upper neck, the forehead (like a hat that is too tight), and around the eyes. The pain is a steady ache, lasting hours to days.  Other than fatigue and mild depression, other symptoms are usually absent.  It is not uncommon to have a tension headache not during periods of stress, but rather after the stress is relieved.  Rarely do tension headaches awaken a patient.

Treatment involves the use of hot or cold applications, relaxation or meditation techniques, and simple pain relievers such as aspirin, acetaminophen, or ibuprofen. These drugs are far more effective taken early in the course of the headache, as opposed to waiting until the pain is severe.   Anecdotally, regular exercise of aerobic intensity often reduces the incidence of tension headaches. The prognosis is benign, but interference with normal activities can be significant. In that event, medical attention may be necessary, and judicious use of anti-anxiety agents, formal counseling, and other measures may be necessary.

Diagnosis rests upon ruling out other causes of headache, which can usually be done without the use of extensive testing. At least initially, a physician diagnosis should be made for this common entity, although recurrences may be quite familiar to the patient, and rarely require medical attention.

Mixed Headache Syndrome
Until fairly recently, the usual headache sufferer was classified as either having migraine or tension headache. Treatment would be given for one or the other, and the results would be observed.  Although most did quite well, there remained a sizable number of patients who would continue to suffer despite treatment.  Many would get partial relief only.

It is now recognized that many patients actually have elements of both tension and migraine or “vascular” headaches, or so-called “mixed headache syndrome.”  As might be assumed, treatment involves delicately balancing the treatment to allow for both components, with variations depending on the nature of the headache, the patients ability to differentiate the two, all the while avoiding the tendency toward overmedication. Diagnosis rests on a very carefully obtained history and examination by a caring physician, who may then use selected additional tests when indicated.  The main point is that a clearcut categorization into the previously discussed types of headaches is not always accurate, necessary or beneficial to the patient.

Temporal Arteritis
This disease is is mentioned here only to state that any headache which comes on for the first time in a person over 50 years of age should be considered as possible temporal arteritis until ruled out by a simple blood test.  The risk of missing this diagnosis is sudden onset of blindness or possibly even death.  It is an inflammation of blood vessels (vasculitis) and can be treated with medications once diagnosed.  Pain with chewing, pain over the scalp when combing one’s hair, or pain in the temple area of the head upon rubbing are signs which should result in an immediate call to your doctor if you are over 50.

Click Here to open the diagram in a larger widnow.

Most of the time, you can go to the eye doctor and get a pair of glasses without any trouble getting used to the them.  There are occasions when a patient can have trouble adapting to the changes in the prescription written by the doctor.  A prescription for glasses is similar to a prescription for medication.  Sometimes side effects can occur after a doctor writes a new prescription.  Yes, even lenses can have side effects.

Whenever a pair of glasses does not seem to work, we like to perform a failure analysis to determine the cause.  This process helps us to prevent from making the same mistake in the future as well as provide you with a clear explanation.  As you can see from the list of causes below, glasses design can be complex with many reasons for problems.

Below are reasons why new prescriptions don’t work for some people.

Getting new glasses during or after vision loss
Patients with vision loss from conditions such as a cataract, diabetes, glaucoma, macular degeneration or other conditions may not have had the real impact displayed to them until they get new glasses.

Despite counseling on part of a doctor or staff on the limitations to expect from new glasses, people may not process the information we try to tell.  It’s as if a psychological block, a type of denial exists, with a subconscious desire that new glasses fix all cases of blurred vision.  Their past experience with visual blur had always been improved with new glasses.  They remember the positive impact new glasses made.  This expectation is probably strong and seems to persist in some patients despite even careful counseling.

When they see for the first time that new glasses didn’t help, it can hit one like a brick wall.  This is the first real impact of their vision loss.  Despite the education, the emotional wall now breaks down.  Denial can turn into anger (see the 12 stages of healing) for the eye care professional who are trying to do their best.  Sometimes we as eye doctors may not have counseled our patients well enough for them to be prepared.

Stress in one’s life can influence our adaptability to new lenses.  Going through a major illness, family changes, grieving, compound our ability to get used to new eyewear.   See another post titled Can Emotions Affect Vision?

Large prescription change
A large change in prescription can challenge our ability to adapt to the new prescription.  Doctor’s will often have to cut the strength of the lens to aid in adaptation.  The prescription can be increased again later to further improve your vision.  We try to anticipate how much you can adapt and prescribe the amount which gives the greatest benefit.  Sometimes we find that this amount can be too much.

Astigmatism or prism not tolerated in the prescription
While a refraction may reveal the presense of astigmatism, it may not mean that a person should be prescribed the full amount or even any of it.  This and other conditions may produce a “pulling sensation” of one or both eyes while you attempt to wear the glasses.  Eye alignment problems such as convergence insufficiency can create similar trouble as well and may mean that vision therapy is required to correct the condition.

Awareness of optical material difference
A few people can notice an improvement in the clarity of glass compared to plastic or between plastic and some other material.  The advantages of a lighter weight lens may not be worth the change you notice.

Awareness of frame or edge of lens
Some individuals can become aware of the edges of the frame.  This effect is more noticeable if a dark color or a bold, plastic frame is chosen.  Some have described a sensation of being “closed in”.  This is often unpredictable and occurs more frequently in people who are getting glasses for the first time.  Selecting a rimless or a metal frame with a thin eyewire can improve this problem.  Contact lenses or refractive surgery are options also.

Monocular cataract (cataract in one eye)
A cataract in one eye can affect how we see with both eyes working together as a team.  Some people still have problems with their eyesight because the cataract still obscures their vision and interferes with their ability to see comfortably with both eyes.  Monocular cataracts can also result in prescription shifts which can cause other problems with adaptation which may be checked off elsewhere.

Binocular cataracts (cataracts in both eyes)
Cataracts in both eyes can deteriorate vision in mild to severe ways.  Eyeglass prescriptions change more frequently when cataracts are present.  An examination may reveal that glasses may help still even with the cataract.  When the glasses do not seem to help however and your problem still continues, cataract surgery becomes the best solution to eliminate the problem if all other eye health factors are normal.

Binocular interference
Glasses are usually designed to give each eye ideal vision by itself and under binocular (two-eyed) conditions.  When new glasses produce problems with eyestrain, headaches, double vision or dizzyness, the problem may be be due to the effect that the glasses are stimulating the brain to attempt to use information from both eyes whereas before only information from one eye was being processed at any given moment.  Unequal refractive error, eye turns, weak or unstable eye muscles and monocular cataracts all can create this type of problem.  Either the predisposing problem needs to be resolved to allow normal binocularity or the glasses will have to be remade to continue the “one-eye only” input style the brain is used to.

Eye alignment problem
A new pair of glasses can result in double-vision in some individuals.  This can happen while looking up or down the lens away from it’s optical center.  Symptoms can also occur while looking at near for a period of time.  Each individual has their own tolerance to how much deviation it can tolerate before giving headaches, eyestrain or double-vision.

Non-Optical problem
Some conditions can not be improved with a regular pair of glasses.  We do our best to try to confirm that glasses will help a person.  Conditions such as cataracts, macular degeneration, glaucoma, diabetic retinopathy can create decreased vision to the point which eyesight can not be improved with regular glasses.  “I just want a pair of glasses that will work,” is the most common comment mentioned to a problem which can not be fixed by glasses alone.  Special visual aids may be needed in these cases.  See the first section Getting new glasses during or after vision loss and Can Emotions Affect Vision?

Changes in vision due to a base curve change in the lens design
Most eyeglass prescriptions allow the manufacturing laboratory to decide on the base curve of the lens to give the best optical performance.  The base curve of a lens refers to the inherent curvature of the front surface.  Some prescription lenses while having the same power may have different curvatures because of the base curve selected by the lab.  Most people adapt to this new curve readily but some can not tolerate the change.  Remaking the same new prescription with the base curve of the old glasses solves this problem.

Image size difference between each eye
If prescription lenses of significant unequal powers are put into a pair of glasses, the image on the retina may not be the same size.  This creates a form of binocular interference as mentioned before.  This can occur by itself, with the development of cataracts or from eye surgery including cataract and retinal surgery.

Bifocal Power – Working Distance Problems
Bifocal strength is determined by several tests during your vision exam.  Each different power of a bifocal has a specific focal range – a zone of clear vision for that power.  The stronger a bifocal is, the closer in the material must be held.  A person’s natural reading distance may not equal the optimal bifocal strength determined in the exam.  Print held at your natural reading distance appears blurred until you hold it closer in.  Remaking the glasses with a weaker bifocal moves the zone of clear vision out to a person’s natural reading distance.  Computer screens often sit further out than a person’s natural reading distance and may require a trifocal, a progressive or a special pair of glasses designed for the computer’s distance.  Some people may notice that a blurred vision zone develops at distances beyond an arm’s distance which can be made clear with neither the top or the bottom of a bifocal lens.  When this happens, a trifocal with a third power segment or a progressive multifocal is needed to keep vision clear at this intermediate distance. There are some cases where vision may have deteriorated to the point where normal print needs to be larger to see it.  An easy way to magnify the print when this happens is to prescribe a strong bifocal.  This stronger bifocal requires a person to hold the material closer than they naturally would in order to help them see well enough to read.

Bifocal height problem
A bifocal can be set too high or too low.  The best height can vary from person to person.  Whenever possible we try to match the current relative height of the bifocal of your last pair of glasses if you are having no problems.

Bifocal line awareness
Some people can become perceptually aware of a bifocal line to the point of distraction.  This awareness normally goes away after the regular two week adaptation period.   If problems continue past this period, a prescription can often be remade in a pair of lineless bifocals or two pairs of glasses with one set for distance and one set for near.

Refractive shift since exam
Cataracts, diabetes, pregnancy and an unstable eye-focusing system are the most common causes for changes in prescriptions which occur in a short time.  Usually the underlying cause needs to be cured before a stable prescription can be determined.

For diabetes, one’s prescription can change as the blood sugar level varies.  Even after control, it takes 5 weeks or longer sometimes to get a reliable and repeatable refraction.

Cataracts can also cause prescription shifts in relatively short amount of time (weeks or months).

Medications can sometimes dramatically affect prescriptions.  We once observed a 7.00 D shift during the use of Topamax, a migraine treatment medication.

Specific Progressive Lens/”Lineless” Bifocal problems

Near area too narrow -  The usable width of most progressive lenses is not as wide as most conventional “lined” designs.  This can be a problem for people who tend to move their eyes only as they read and do not move their head.  If an acceptable wide near area progressive can not be found then a traditional bifocal or reading glasses may be needed.

Trouble adapting to lens periphery – The periphery of a progressive lens is blurry and can produce a swimming motion which may not be well tolerated by some.  This can produce motion-sickness like symptoms especially in people prone to this problem.  Traditional bifocals or single vision based glasses (one pair for distance and/or one pair for near) may be needed.

Lens Aberrations

Spherical aberration Some newer lens designs can get rid of distortions which make walls appearred bowed in or out.  Aspheric lenses can correct for this distortion but can in some create symptoms similar to base curve changes.  Traditional spherical designs can help correct this problem.

Chromatic aberration Colored fringes on lights may be noticed with high prescriptions in lens materials described as “lighter and thinner”  Chromatic aberration is caused by high index lenses that refract light differently for each wavelength which results in images splitting up and developing colored fringes.  This effect is more pronounced the further away from the optical center you view an object.

Waves Waves are defects in the surface of the lens.  The lens is not perfectly spherical in shape and distorts light in specific places creating a distortion in the image which can appear like waves.

How much change can humans adapt?
A study looked into the ability to adjust to new viewing conditions.  This experiment tested the absolute limits the human visual system could adapt.

The study paid college students to wear special glasses every waking moment of the day.  The students were told to put the glasses on from the first moment they awakened to when they went to bed.  They were to do everything with them on even shower and bathe with them on.

One half of the glasses were a simple lens with no prescription in it for a control.  The experimental half had glasses that turned the world upside down.  Up was Down and Left was Right.

The experimental group had a terrible time.  Imagine trying to navigate the world that’s upside down.  Walking was awkward and unsteady with poor balance.  Subjects developed headaches, eyestrain even nausea and vertigo.  Their handwriting was awful. They had trouble reading, eating, typing and moving around.  These symptoms lasted about 3 weeks.  Then remarkabily they all adapted.  In the second half of the experiment the glasses were taken away and the symptoms came back while adjusting back to the normal world.  Their recovery was much shorter – 3 days instead of 3 weeks.

This experiment showed that with extreme prescriptions, adaptation is possible.  It also showed that a motivated individual will work at keeping their glasses on to allow adaptation.  In the experiment, college age students were being paid to participate.  They had a motivation to succeed to earn the money.

In the real world

In the real world, we can’t expect people to change to this dramatic amount.  Fortunately no eyewear prescription is ever this disruptive.  We can ask that they try to give it 3 weeks of real committed effort.

Another factor involves age.  Subjects age 20 will adapt more easily than subjects age 30 and age 30 subjects will adapt more easily than age 40 and so on.  Neurological adaptation slows over the decades.

A 70 year old with real vision problems caused by a retina disease will be a real challenge.  There will never be an instant fix in acclimatizing with glasses. Their expectations are based on previous glasses instantly sharpening vision and feel disappointed when this is not achieved.  Or the glasses may swim and swirl around because somehow they are “too strong” or “too weak” or “not right.”

Even folks age 40 can have trouble adjusting to their first progressive lens.  The same observations have been reported in people getting used to a no line bifocal.  This effect is more common if a history of motion sickness or a condition like Meniere’s disease exists.

Hang in there.  Eye care professionals do the very best we can to help.

Getting a new pair of glasses
Patients with vision loss from conditions such as a cataract, diabetes, glaucoma, macular degeneration or other conditions may not have had the real impact displayed to them until they get new glasses.

Despite counseling on part of a doctor or staff on the limitations to expect from new glasses, people may not process the information we try to tell.  It’s as if a psychological block, a type of denial exists, with a subconscious desire that new glasses fix all cases of blurred vision.  Their past experience with visual blur had always been improved with new glasses.  They remember the positive impact new glasses made.  This expectation is probably strong and seems to persist in some patients despite even careful counseling.

When they see for the first time that new glasses didn’t help, it can hit one like a brick wall.  This is the first real impact of their vision loss.  Despite the education, the emotional wall now breaks down.  Denial can turn into anger (see the 12 stages of healing) for the eye care professional who are trying to do their best.  Sometimes we as eye doctors may not have counseled our patients well enough for them to be prepared.

Crime scene witness differences
Eyewitness testimony in the previous century was considered the best evidence possible.  Now it is considered nearly the worst.

Emotional factors influence the reliability and accuracy of witness descriptions.  The stress factors involve in a crime can influence the ability for a witness to recall events accurately.  Several studies have shown that different people will describe events differently and offer differing descriptions of the perpetrator.  Differences even occur when stress is eliminated and witnesses just watch a video of events.

Color Vision and Emotion
One study from Caltech suggests that color vision evolved and improved to help humans see emotion.  In addition to food identification, the neurobiologist theorized it was socially important for humans to interpret the emotions of others.

Post Traumatic Stress Disorder

PTSD has well documented effects on vision. The most common effect is blurred vision.  The study quoted notes several possible ways blurred vision can occur but the symptom itself can be vague and difficult to discover why.  From a clinical perspective, I have observed patients reject new eyewear with reports of blurred vision even though all tests were exactly on target with the prescription.  Stress can cause blurred vision.  Not just severe stress like PTSD but any greater than usual stress such as divorce, social changes, life changes, major illness of self or a loved one, and employment-related concerns.  The ability to adapt by a minor change in a prescription may be the straw that breaks the camel’s back if one is already coping at their maximum ability of other stressors.

How do we see?

When we look at an object, called the “object of regard,” each eye forms an image of the object on the retina, the light- sensitive membrane lining the inside of the back of the eye.  The image produced is termed the “image of regard.”  After being processed in the retina, it is converted into electrical impulses which are transmitted along the optic nerve to the visual centers of the brain.  Although the brain is presented with a pair of images of the same object, one from each eye, it fuses the two images into one.  The result of this process is what we think of as our vision.

A child’s eye-brain system is amazingly plastic or pliable and is not mature until the child reaches eight or ten years of age.  Even past this age, recent studies show evidence of remarkable plasticity well into adulthood.  But this does not imply that a younger child’s vision cannot be normal.  Indeed, the average child has 20/20 visual acuity by the age of nine months.  None-the-less, subtle development does occur in this system until the child is considerably older.

Each eye has brain cells associated with it that respond only to that eye. There are other cells in the brain that respond only to stimuli from both eyes.  These are termed binocular cells.  Because of the plasticity of these eye-brain connections in younger children, both types of cells need continuous input to ensure proper maturation of the visual system.  Any disruption in this maturation process may cause problems.  Amblyopia is the term for a major interference with this visual development.

In some ways each eye is designed to be competitive with its counterpart, i.e. there is a rivalry between the two eyes for the brain’s attention.  When something interferes with one eye’s imaging and processing functions, that eye can lose vision and become amblyopic.  The eye itself may function normally without any permanent damage, but the brain becomes less and less attentive to it and begins to rely more and more on stimuli from the other eye.  An actual loss of cells, including binocular cells, occurs in the brain area serving the amblyopic eye.

Causes

Any condition that interferes with normal retinal processing or clear vision can produce amblyopia.  There are three main ways that this interference can occur:

1.  Strabismus — A constantly crossed eye does not image the object of regard.  Therefore, a child with esotropia, or crossed eyes, who always looks at the world with his left eye while his right eye is crossed does not receive the same visual information in each eye.  The deviated right eye receives deprived information.  Because of the rivalry in the brain, the visual input from the constantly deviating eye is ignored or shut off and more and more the brain depends on visual information from the straight eye.  Ultimately, the constant deviation and poor visual processing in one eye leads to amblyopia in the brain cells serving that eye.

2.  Deprivation — Anything that prevents a clear picture from reaching the retina can produce amblyopia.  A classic example is a cataract in a child.  When an adult develops a cataract, surgical treatment usually corrects the vision to 20/20 whether the cataract had been present for one month, one year, or even ten years.  But in a child, even if a cataract has been present for a short time–even a matter of weeks–surgery to remove the cataract may not restore good vision.  The youngster’s visual brain cells, having not received clear images through the cataract, may already have become amblyopic.  Other disorders that can cause deprivation are corneal scars and opacities, and opacifications elsewhere in the system caused by a variety of eye diseases.

3.  Anisometropia — This is very common, and unfortunately, a very insidious type of amblyopia because it is without any sign or symptom in a child.  Anisometropia is by definition an imbalance between the refractive error of each eye.  That is, one eye has a need for a stronger spectacle correction than the other eye.  For instance, the right eye may have two units of farsightedness, whereas the left eye may have four units of farsightedness. Consequently, the left eye receives a more blurred image than the right.  That image is ignored and the brain cells serving that eye deteriorate while the brain concentrates on the clearer image from the right eye.  This process may also occur with astigmatism or nearsightedness.

Diagnosis

The diagnosis of amblyopia requires a complete optometric exam.  As noted above, a normal child does not reach 20/20 visual acuity until nine months of age; however, the vision can be checked as early as three to four months of age. The symmetry of vision rather than absolute acuity is assessed initially.  This comparison between the two eyes may detect a difference in their ability to see clearly.

Ideally, most children should receive an initial visual screening from their pediatrician or family physician at approximately six months of age.  If a problem is detected, or if there is a suspicion of an abnormality, a complete vision examination by an optometrist is recommended to assess the visual acuity of each eye, to look for the presence of any eye disease, such as strabismus or cataract, and to determine the refractive error or power of glasses that might be prescribed.

Another common source of amblyopia diagnosis is a screening program which may be carried out by certain organizations, clubs, or day care centers, etc.  If a child goes through a screening program and an abnormality is suspected, he should receive a referral to an optometrist.  Primary care physicians and group screening centers can only suspect the problem; it is the optometrist that must confirm the diagnosis and carry out the definitive treatment.

Treatment

Treatment for amblyopia is twofold: correction of the underlying problem and therapy of the amblyopia itself. Obviously the treatment for the underlying disease, whether that be a strabismus, an anisometropia, or a unilateral cataract, depends on the particular condition that is present.  The treatment for amblyopia is best done in a step-wise process.   The child may be placed in glasses and occlusion or patch therapy to cover the good eye.  Several non-prescription elliptical eye patches are commercially available.  Like BandAids, they stick directly to the skin with their own adhesive.  They cannot be stuck to the glasses, as the child will simply look over the top of the frames.  Occluding the good eye forces the brain to rely on the amblyopic eye, slowly reversing the brain cell deterioration.  Recovery usually takes several months, although it can occur in a shorter period of time in very young children.  Eye patches may be worn for anywhere from several hours per day to all the waking day.  Some optometrists prefer intermittent patching, i.e. two hours per day, eight hours per day, etc., while others advise full-time occlusion.  This type of treatment howe ver, does very little to restore the function of the binocular cells which require input from the eyes at the same time.  Visual acuity may improve but binocular vision may not be restored.  

Studies in recent years have also reinforced the effectiveness of using cycloplegic eyedrops as a patching alternative.  These are drops (the same as dilating drops) which “turn off” the focusing ability of the better seeing eye to help stimulate the amblyopic eye into better use.   This can have a similar effect as a patch but without the cosmetic appearance issues.  One study has even shown that weekend use of cycloplegic eyedrops can improve vision – allowing children to focus efficiently during the school week for studying.

The use of vision therapy continues to evolve and improve in the treatment of amblyopia.  New studies now show substantial improvements in vision in patients older than nine years, the age which used to be thought that little could be done for treatment.  The goal of vision therapy is to improve visual acuity by the use of activities to stimulate and develop vision in the weaker eye and to restore or improve binocular vision through the use of activities which strengthen a person’s eye-teaming abiltiy.

The most important concept in the treatment of amblyopia is the age of the child.  The earlier the amblyopia is detected, the better the potential for succes with treatment.  The above limitations relate to the plasticity of the brain that was mentioned earlier.  The eye-brain is flexible enough to reverse the cell deterioration in the first few years of life, but after that crucial time period, the amblyopic condition becomes more difficult to remediate.

There is one other form of amblyopia treatment that is much less commonly employed and  involves placing an eye drop in the good eye causing the vision to blur in that eye more than the other eye.  As with patching, the idea is to stimulate the brain’s attentiveness to the amblyopic eye.  Most doctors use this method sparingly.

Treatment options for amblyopia and success rates are better than ever thanks to newer techniques and recent reseach validating these methods.  If treatment has been limited to only one of the above techniques then the patient should seek further treatment.  Amblyopia treatment involves a commitment between the doctor, the patient and the parent to best treat the condition.

Floaters can appear intermittently, drift around and blur vision.

Floaters refer to the apparent floating spots that appear in your central vision.  Floaters are small cloudy particles present in the back cavity of the eye called the vitreous and are commonly seen by many people.  Floaters are often remnants of a blood vessel which once existed between the optic nerve and the lens.  Before you were born, this vessel broke up into many bits.  Floaters  can also occur when new problems begin in the posterior segment of the eye.  Retinal tears, holes and detachments have the potential to produce many new floaters often described as a  “shower of gnats”.

Vitreous Detachments occur in most people as we age.  A vitreous detachment will produce both flashes and floaters.  Vitreous detachments occur when the normally gel-like vitreous breaks down into a less viscous, watery state.  This will often create fears of a retinal detachment in some people.  The truest symptom of a retinal detachment is the sudden loss of peripheral or central vision.  This is often described as a curtain descending over one eye.  Unfortunately, many individuals are not aware of the loss of a single eye’s peripheral vision until it is too late.  Only a dilated eye examination will reveal if the symptoms are caused by a retinal or vitreous detachment.

The best thing to do if you notice a sudden onset or increase in flashes, floaters or curtains is to call our office so we may directly inspect the retina.  Do not delay calling us even if it occurs at night or on a weekend.

A number of different conditions of the vitreous or retina can produce floaters.

Undilated pupils can limit the view inside

By making the pupil larger, we can see more

Dilation of the pupil refers to the technique of instilling eyedrops which temporarily make your pupils larger.  This gives your doctor an opportunity to see more of your retina when he looks into your eye to examine its health.  It’s a lot like looking into a keyhole to see what’s inside a room; the bigger the keyhole, the more you can see.

A commonly noticed effect of the drops is the temporary reduction in focusing ability to see things at near clearly.  For some younger patients this effect is an advantage to the doctor who can utilize it to determine a more accurate prescription for the patient.  The blurriness at near gradually reduces quickly and the ability to focus at near again should return within one hour.

Dilation begins to wear off in 1/2 hour and is near normal after 4 hours.  During this time, you may receive some special temporary sunglasses to wear to protect you from bright light.  Your vision examination is a lot more than just a test for glasses.  Exams with routine dilation of your eyes are more common now than in the past.  This helps assure that you receive the highest quality vision care that is available.