|Year : 2021 | Volume
| Issue : 4 | Page : 884
Brückner's test for squint explained - A hypothesis
Amber Amar Bhayana, Priyanka Prasad
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India
|Date of Web Publication||09-Oct-2021|
Dr. Amber Amar Bhayana
Dr Rajendra Prasad Centre, AIIMS, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Bhayana AA, Prasad P. Brückner's test for squint explained - A hypothesis. Indian J Ophthalmol Case Rep 2021;1:884
In case of esotropia/exotropia [Figure 1]a, the path of light traveled for the reflex formation is normal in the non-deviated eye (black line, [Figure 1]c), but is shorter in the deviated eye (green line instead of the normal black line—chord instead of diameter considering the eye cross-section to be a circle, [Figure 1]b). This results in the apparent shorter axial length to the traversing light in the squinting eye and resultant asymmetric hyperopia apparent in the squinting eye as compared to the normal eye. Hyperopia causes an asymmetric crescent when Brückner's test,, is done which is seen as an asymmetric brighter reflex (not seen in the normal eye). Roe and Guyton in their article have described “off-axis optical aberrations” in the squinting eye which decreases the conjugacy of the ophthalmoscope to the retina causing light to spillover into the peephole increasing the intensity of the red reflex to increase. Similarly, they have described optical blur in case of anisometropes to cause spillover to peephole when compared to the normal eye which focuses sharply on the mirror rather than peephole, and thus, a brighter reflex in the refractive error eye. We believe it is the apparently induced hyperopia due to the apparent axial length shortening for the straight traversing light in the squinting eye which gives rise to a brighter glow as compared to the normal eye and forms the basis of the famous “Brückner's test.”
|Figure 1: (a) Esotropia; (b) Squinting eye-path traveled by light in the Brückner's test is the green line (shorter) instead of the black line (normal); (c) Normal eye-path traveled by light in the Brückner's test is a black line—the normal anteroposterior diameter|
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| References|| |
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Kothari MT. Can the Brückner test be used as a rapid screening test to detect significant refractive errors in children? Indian J Ophthalmol Case Rep2007;55:213-5.
Bhayana AA, Prasad P, Azad SV. Refractive errors and the red reflex- Brückner test revisited. Indian J Ophthalmol Case Rep2019;67:1381-2.
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