There are a variety of methods used to screen children, depending on the age of the child tested. In babies, the ability to fix and follow an object is assessed. Using either an Ophthalmoscope or Retinoscope, the red reflex is analyzed. If there is a dulling of the reflection, it may indicate a potential issue. If the reflex is assymetric, it is a potential indicator of amblyopia or a lazy eye. The American Academy of Pediatrics now supports the use of Photoscreeners and Autorefractors to assess children. These instruments assess the red reflex of the eye and using specific algorithms, predict the probability of amblyopia and strabismus in these children. Some of these instruments assess refractive error and pupil size as well. Many children with amblyopia try to “cheat” the standard vision test. Using automated instruments prevents these patients from escaping detection. Corneal light reflex testing can be easily done in children of any age. Using a pen light, or even a simple flashlight, the position of the light reflection from the front surface of the eye is assessed. This test is only accurate if the child is looking directly at the light. The reflex should be in the center of both pupils. If one eye has a reflex in the pupil and the other is decentered, this could be an indication that that child has strabismus.
Subjective visual acuity testing is still the gold standard in terms of detection of amblyopia. Successful testing requires a cooperative child. The Snellen eye chart is the most reliable. If children do not know their letters, the Allen and Lea symbols are often used. It is important, when examining a child, to make sure one eye is being tested at a time. In my office, I have the patient’s parent hold a tissue over the eye that is not being tested. This insures that the patient isn’t peeking. Most children simply do not want to “fail” any test so will try to look with their good eye. Glasses have become so fashionable that children sometimes pretend not to see in order to get glasses. If your child tests poorly, however, I would not assume this and would let a Pediatric Ophthalmologist determine if this is the case.
Vision screening should be done throughout childhood. Automated Photoscreeners are useful in children as young as a year old. The most common photoscreeners include, the Welsh Allyn Suresight, the iscreen and the Plusoptix. There are apps that are now available to assess vision remotely, such as the Go Check Kids app. If your child has a family history of systemic disease manifesting in the eye, amblyopia or strabismus, it is worthwhile to have a comprehensive examination by a Pediatric Ophthalmologist regardless of the screening result. As a parent, if you suspect your child has difficulty with their vision, it is also worthwhile to be examined thoroughly.