Bruckner Testing7:00 AM
Wouldn’t it be great if there was a quick and easy way to check for the potential for reduced vision in an eye without having to rely on a child to read letters on a chart? Think about all those times that you need objective results – when a child is too shy, or just not wanting to cooperate, or even in patients that cannot communicate to tell you what they see. Luckily optometrists have methods to get around the limits of testing very young, precocious, shy, or nonverbal patients. The Bruckner Test is one such method that helps unlock your child’s visual world without them having to do anything more difficult that look at a light.
|An abnormal Bruckner test shows unequal light reflexes between the eyes. The lighter/brighter reflex (right) is the eye with the potential amblyopia. via|
What it Tells You: The Bruckner Test uses the light reflex from the retinal tissue in the back of the eye to assess visual ability. If a child has equal acuity in each eye, we would expect the light reflex coming from the back of the eye to be equal. But if one eye shows a much stronger (or “brighter”) reflex than the other, the doctor knows there is a risk for amblyopia (or lazy eye as it is often called in layman’s terms).
|All you need! via|
How To Perfom:
- Stand 1 meter or about 3 feet away from the patient.
- Tell the patient to look at your light (typically they will do this anyway, but you can turn off the room lights to minimize distraction if needed)
- Compare the brightness and color of the light reflex between the right and left eyes.
The macula is the area of the eye dedicated to best fine detailed, central vision. To achieve best visual acuity, we need to use our macular retinal photoreceptors when we look directly at any visual target. If the patient is using the macula to focus, we would expect a deep red reflex to appear in our direct ophthalmascope. This is because the macula is our area of densest photoreceptor presence and thus the darkest pigmented point in the retina. If there is an inequality of the color and brightness of the light reflex, the eye with the lighter and brighter reflex is the eye that is potentially amblyopic. If you recall your student days: Bright is Bad in Bruckner’s was a common memorization tool. The brighter reflex results because the eye is either not using the macula for fixation, or not accurately focusing light on to the macula. Because the lighter reflex could be from several causes, Bruckner’s test can only tell you that this eye is potentially amblyopic, but cannot differentiate between refractive error or strabismus (an eye turn -- read more here).
|The macula is the area of darkest pigmentation in the retina, so if light is focused here and reflecting back from our direct scope, we'd expect a dark, red reflex. If light is hitting another part of the retina, then the reflex won't be as dark or red, causing the abnormal Bruckner test response! via|
Bruckner Testing gives you a quick way of assessing any potential for amblyopia, but won’t tell you the degree of amblyopia or the cause of the amblyopia. It’s a great way to find a problem, but it is only a starting place! Bruckner Test reflexes are especially useful because they can be used in screening young children when assessing visual performance isn’t always easy or accurate. And
Bruckner testing is reliable-- studies suggest an accuracy of 84% in amblyopia detection in patients with strabismus or a prescription difference of 3 diopters or more. The best part is that once you get comfortable, it takes less than 10 seconds to accurately perform this screening test and move to the next item on your list.
|Dr. S is a pediatric and vision therapy specialist and COVD fellow practicing in St Louis, Missouri|