An Interview with Dr. Steve Galanter: What is Amblyopia and Why are Teachers so Concerned about it?

Sep 26, 2011 by

Michael F. Shaughnessy
Eastern New Mexico University
Portales, New Mexico

Dr. Stephen Galanter has lectured to educators and school nurses on the subject of vision and vision screening and has an informed perspective on how vision difficulties impact students, teachers, parents and others involved with a child’s education. He is in private practice in Philadelphia, PA and president of Visual Technology Applications, Inc. the developer of the VERATM school vision screening program, which can be found at www.visualscreening.com.

1)      First of all, what exactly is amblyopia and what causes it?

Amblyopia is said to exist when there is a reduction in visual acuity out of proportion to any physical abnormality in an eye. In fact, most amblyopic eyes are otherwise physically normal. It’s generally caused when the retina of one eye receives an unclear image for an extended time. The visual pathway from the eye to, and including the brain loses resolution, or, in the case of a developing infant, doesn’t attain it.

2)      I have heard this referred to as “Lazy eye“. Can you explain?

“Lazy eye” is lazy way to say “amblyopia”. Actually, it’s a lay term for an eye that’s less well used, which may refer to an amblyopic eye but can also refer to an eye that turns, usually outward. This, however, is called “exotropia”. While we’re on this, if an eye is exotropic, it can become amblyopic, as the brain will suppress the image in that eye to avoid debilitating double vision.

3)      Do they still use patches or just corrective lenses?

The answer is one or both. Corrective lenses are used to provide the clearest optical image to the retina of the amblyopic eye, and patching of the better eye is used to encourage use of the amblyopic eye. This is done most commonly with an eye patch, but a frosted eyeglass lens, opaque contact lens or other mechanical or pharmaceutical block to the good eye has also been used, albeit somewhat less frequently. Bilateral patching is least frequently used*.

4)      Does amblyopia cause blurry vision?

Technically no, since amblyopia IS blurry vision in an optically corrected, otherwise normal eye. In professional practice, when we can’t explain reduced visual acuity in an otherwise normal eye, we then say the eye is “amblyopic”.

5)      Is it possible for a student to have both amblyopia AND to be color blind or color deficient?

Yes, because color “blindness” (which is uncommon; most affected people are color deficient) is a different condition. It is a reduced sensitivity to certain wavelengths of light; i.e., colors, and occurs at the level of the retina, where there is a fault in the development of sensitivity of the retinal cones. Amblyopia results in reduced visual acuity, not color discrimination and so you could have both.

6)      What is the treatment for ambylopia?

Treatment generally consists of glasses to correct any significant refractive error in the affected eye(s) and patching or blurring the better eye to force use of the amblyopic eye. If the eye is also severely turned, muscle surgery may be used to align the eye. If the eye turn is less severe, surgery may be avoided if muscle training can bring the eye into alignment. Then, perceptual training of the weaker eye and exercises to integrate the weaker eye with the stronger eye can be very helpful in certain cases.

7)      What does autorefract mean? Why is this word used so often in reports?

Autorefraction is an electronic, objective measurement of a person’s refractive error. It is taken by an electronic device which bounces light of certain wavelengths off the retina and analyzes the degree-specific convergence or divergence the eye imparts to the exiting light. The readout is in the same form as an eyeglass prescription. In our office, we use autorefraction as part of our pre-examination screening to better understand a patient’s symptoms and the direction of change a patient’s prescription may require. In the context of amplyopia, an autorefractor gives a quick indication of whether any refractive error is significant enough to result in reduced use of the eye.

As well, devices called photoscreeners help to determine whether a refractive error, turned eye(s) or amblyopia exists by imaging the way light reflected out of eyes with each of these conditions appear when compared to normal eyes. Photoscreening is quite effective in pediatric and non-verbal populations.

8)      What is refractive amblyopia?

Refractive amblyopia is said to exist when it is caused by a poorly focused image to a retina. This is in contrast to amblyopia caused by an eye turning in or out and the brain suppressing the vision in the misaligned eye to avoid diplopia, or double vision. You could, again, have both of these conditions at the same time, i.e., a misaligned eye with a significant refractive error, or even an eye that drifts (usually outward) because of severe refractive amplyopia.

9)      What are the educational implications of this?

The implications are basically the same as any vision condition such as nearsightedness, farsightedness, astigmatism or a binocular vision difficulty, which causes increased effort to “see the board” clearly or read easily. Faced with an uncorrected or unidentified vision deficit, many students will do poorly in school.

We rely on pediatricians to check a young child’s visual acuity and whether an eye turns abnormally well before they enter school and to initiate a referral to a vision specialist. After that, a thorough school vision screening should catch these students since amblyopia results in reduced visual acuity, and the doctor will then make the exclusionary diagnosis of amblyopia.

Unfortunately, many school vision screening practices fail to identify many vision deficits or to follow-up on vision referrals, which are some of the reasons we developed the VERATM screening.

10)   I have heard that early identification is imperative. Tell us about this?

The younger an amblyopic person is, the greater the chance that correcting any optical defect and forcing use of their amblyopic eye will improve visual acuity. Infants develop visual abilities after birth. If they have an abnormal relationship between the two eyes, any developing visual and behavioral patterns will become more embedded with time and more difficult to correct. An excellent summary of visual development can be found at: http://www.aoa.org/x9420.xml

11)   What do teachers and parents need to know?

At the risk of oversimplifying, both should know that that a thorough eye examination for each child is necessary whether or not a school vision screening is passed. This is why so many states and professional organizations promote mandating an eye exam before a child starts school. Teachers should know that amblyopia will likely be indistinguishable from other vision difficulties and their general vigilance for students with vision difficulties should be maintained. Parents should know that amblyopia rarely occurs once a school-age child has demonstrated normal vision or had their vision corrected to normal, and so it’s not something they need to continue to worry about throughout childhood. And of course, every school should have an effective vision screening, reporting and referral program to catch these types of problems.

12)   What have I neglected to ask?

Nothing, I think. Thank you, Mike, for the opportunity to participate in an interview once again.

 

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