Eye Examination and vision assessment are vital for the detection of conditions that result in blindness, signify serious systemic disease, lead to problems with school performance, or at worst, and threaten the child’s life.
Through careful evaluation of the ocular system, retinal abnormalities, cataracts, glaucoma, retinoblastoma, strabismus, and neurologic disorders can be identified, and prompt treatment of these conditions can save vision or even life.
Examination of the eyes should be performed beginning in the newborn period and at all well-child visits. Visual acuity measurement should be performed at the earliest possible age that is practical (usually at approximately 3 years of age).
Early detection and prompt treatment of ocular disorders in children is important to avoid lifelong permanent visual impairment.
“Many parents today are under the impression that the vision screening their children receives from the school nurse is sufficient,” says Jeffrey R. Anshel, DS, OD. “The screening [at school] will determine the child¹s distance vision but what is missing is the near vision. Very few eye screenings include this much-needed exam. Just as children should visit the pediatrician and the dentist, they should also see a licensed eye care provider to screen for vision problems.”
A comprehensive eye exam includes testing and evaluation of visual skills (function, performance, etc. In the absence of complete testing, common pediatric vision problems can go undetected, and, in some cases, can be misdiagnosed as a learning disability or behavioral problem. This page lists some of the visual skills which need to be evaluated as part of a child’s comprehensive vision examination.
IMPORTANT NOTE : Many school eye or vision screenings test only one of the visual skills listed below — that is, Acuity-Distance (clarity of sight in the distance, 20/20 eyesight as measured by the standard Snellen eye chart).
A child’s comprehensive eye examination should include testing of the following visual skills, ALL of which are important aspects of normal, healthy human vision.
- Acuity – Distance Vision : visual acuity (sharpness, clearness) at 20 feet distance.
- Acuity – Near Vision : visual acuity for short distance (specifically, reading distance).
- Focusing Skills : the ability of the eyes to maintain clear vision at varying distances.
- Eye Tracking and Fixation Skills : the ability of the eyes to look at and accurately follow an object; this includes the ability to move the eyes across a sheet of paper while reading, etc.
- Binocular Vision or Fusion : the ability to use both eyes together at the same time.
- Stereopis : binocular (two-eyed) depth perception.
- Convergence and Eye Teaming Skills : the ability of the eyes to aim, move and work as a coordinated team.
- Color Vision : the ability to differentiate colors.
- Reversal Frequency : confusing letters or words (b, d; p, q: saw, was; etc.)
- Visual Memory : the ability to store and retrieve visual information.
- Visual Form Discrimination : the ability to determine if two shapes, colors, sizes, positions, or distances are the same or different.
- Visual Motor Integration : the ability to combine visual input with other sensory input (hand and body movements, balance, hearing, etc.); the ability to transform images from a vertical to a horizontal plane (such as from the blackboard to the desk surface).
Remember, an eye exam that tests distance vision only is NOT an adequate evaluation of a child’s visual development. The visual skills listed above contribute significantly to a child’s success with reading and school achievement. Learn more at Success in School: 20/20 Eyesight is Not Enough!
What Is Amblyopia (Lazy Eye)?
Amblyopia, commonly known as lazy eye, is the eye condition noted by reduced vision not correctable by glasses or contact lenses and is not due to any eye disease. The brain, for some reason, does not fully acknowledge the images seen by the amblyopic eye. This almost always affects only one eye but may manifest with reduction of vision in both eyes. It is estimated that three percent of children under six have some form of amblyopia.
Causes Of Lazy Eye
Anything that interferes with clear vision in either eye during the critical period (birth to 6 years of age) can cause amblyopia. The most common causes of amblyopia are constant strabismus (constant turn of one eye), anisometropia (different vision/prescriptions in each eye), and/or blockage of an eye due to cataract, trauma, lid droop, etc.
Amblyopia is a neurologically active process. In other words, the loss of vision takes place in the brain. If one eye sees clearly and the other sees a blur, the brain can inhibit (block, ignore, suppress) the eye with the blur. The brain can also suppress one eye to avoid double vision. The inhibition process (suppression) can result in a permanent decrease in the vision in the blurry eye that can not be corrected with glasses, lenses, or lasik surgery.
Detection And Diagnosis Of Lazy Eye
An eye exam by a pediatrician or the 20/20 eye chart screening is not adequate for the detection of amblyopia (and other visual conditions). The most important diagnostic tools are the special visual acuity tests other than the 20/20 letter charts currently used by schools, pediatricians and eye doctors. Examination with cycloplegic drops can be necessary to detect this condition in the young. Since amblyopia usually occurs in one eye only, many parents and children are unaware of the condition. Many children go undiagnosed until they have their eyes examined at the eye doctor’s office at a later age. Comprehensive vision evaluations are highly recommended for infants and pre-school children.