• Comprehension reduces as reading continued: loses interest too quickly
• Mispronounces similar words as continues reading
• Blinks excessively at desk tasks and/or reading; not elsewhere
• Holds book too closely: face too close to desk surface
• Avoids all possible near-centered tasks
• Complains of discomfort in tasks that demand visual interpretation
• Closes or covers one eye when reading or doing desk work
• Makes errors in copying from chalkboard to paper on desk
• Makes errors in copying from reference book to notebook
• Squints to see chalkboard, or requests to move nearer
• Rubs eyes during or after short periods of visual activity
• Fatigues easily; blinks to make chalkboard clear up after desk task

Accommodative Insufficiency

Accommodative insufficiency occurs because of the eye can not maintain clear vision at near.

Ill-Sustained Accommodation

Ill-sustained accommodation is similar to accommodative insufficiency except print may initially appear clear and easy to read without effort.  With time, the task at near begins to require more effort to focus.  Blurred vision, eyestrain and headaches can occur with sustained effort.  A simple visual acuity test at near (as what is frequently done during a vision screening) will usually not detect this problem.

Normal Focusing

Our focusing system is usually quite fast at focusing.  Most people can focus at near in about 1/5 of a second as simulated above.

Accommodative Infacility

With accommodative infacility, there is a delay in the clearing of the print.  The simulation above shows how a student with this problem would be slowed.  Copying information from a chalkboard to your desk is a frequent activity in a classroom.  It takes the student longer to obtain and transfer the information.

For all of the above problems, lenses or vision therapy or a combination of both may be prescribed.  The success of treatment is quite high.  A few cases may require only short term use of lenses or vision therapy while others may have a need throughout their youth for this type of help.

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.

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.

Amblyopia is a condition of underdeveloped vision.  Findings of underdeveloped vision can be considered a constellation (grouping) of findings that include lowered visual acuity, decreased accuracy and ability of ocular movements such as pursuits (slow eye movements) and saccades (fast eye movements), decreased focusing abilities and decreased visual processing skills.   Decreases in stereopsis (3D vision / depth perception) and restrictions in visual field (tunnel vision) can be measured clinically.   Most cases develop as a result of an eye turn (strabismus) or undercorrected refractive error.  Amblyopia can occur in 2.5% of the population, making it responsible for more loss of vision than all ocular diseases and trauma combined.

Streff syndrome is a different type of amblyopia labeled psychogenic.  This type is under-reported in the medical literature.  Psychogenic means the origin is in the mind or more accurately in the parts of the brain that process vision.  Psychogenic amblyopia can involve voluntary and involuntary types.  Voluntary psychogenic amblyopia is also known as malingering – a process of faking a condition for some type of gain.  Involuntary psychogenic amblyopia involves vision and vision processing problems that occur in a patient who is not malingering.  Their problem is real, measurable and not being faked for some type of gain or attention.  There is no organic base for the problem meaning that there are no observed structural or anatomic anomaly that can account for the problem.  Saying that a problem is not organic however does not account for possible genetic, biochemical, electrophysiological or other abnormalities that may be present but for which we do not have the technology or background to identify them.  The word functional means that the normal expected work or function that a process is supposed to offer (such as correct focusing) does not occur.

Streff syndrome is believed to develop as a result of stress.  Hans Selye classifies stress as eustress – stress affiliated with change for the better such as marriage, getting an A on a test, being accepted into college or distress – stress affiliated with change for the worse such as divorce, family problems, substance abuse, emotional abuse, health problems.  A reaction from too much stress can include behaviors that trigger a person’s alarm mode especially if there is to0 much stress leading to an overload.

A diagnostic pattern has been described for patients susceptible to Streff syndrome.

• Prepubescent or early pubescent ages 10 – 14
• Females more frequent than males
• Visual acuity worse than 20/20 to  20/200
• Visual skills problems in ocular movements, ocular focusing, visual information processing.

Symptoms noticed by patients, parents and teachers can include:  a sudden decrease in academic performance, lack of desire to pursue homework, increased errors on homework, blurred vision at distance and at near, blurred vision of varying amounts which can come and go but usually stay blurry and headaches.

Sometimes the eye care professional can elicit a recent history of family stress, social stress, recent relocation.

The main clinical treatment of this condition is the use of a low plus eyewear prescription.  This may be in the form of reading glasses or a multifocal.  The effect of this prescription reduces the visual stress by just enough to allow the visual system to re-engage, organize and process information efficiently.  Results are usually quickly obtained with improvements seen within a few weeks.    Some cases may require vision therapy to improve eye movements and focusing.   In cases unresponsive, eye care professionals should always rule out organic pathology both at the time of the initial diagnosis and later on.

In 1962, Dr John Streff first published a description of this condition.  Articles in the optometric literature are more numerous than ophthalmological literature.  This condition needs more research.  The condition is considered functional in nature.  Functional means no organic pathology exists but the software programming of the visual system is inefficient or not working as it should.

More Information:  Streff Syndrome.pdf
(an information pamphlet written by Paul Harris, OD on this condition)

Much of this information is adapted from: Press, Leonard. Applied Concepts in Vision Therapy, St. Louis:  Mosby 1997

Cook, Douglas T & Maples, WC. NSUOCO Vision Therapy Pocket Reference, Tahlequah:  SITE 1994