Correspondence Address:
Dr. Shorya V Azad
Dr. R P Centre, AIIMS, New Delhi - 110 029
India

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Sir,

Kothari MT has described the use of Bruckner test[1] as a method for screening refractive errors[2] by documenting that a bright crescent is seen superiorly in hyperopes and inferiorly in myopes. But neither has this been verified with any other equipment nor has any explanation been given for the formation of crescent. We did a similar red reflex test with an indirect ophthalmoscope to find out any difference against direct ophthalmoscope and found results to be exactly opposite.

We found when a dilated eye is seen through an indirect ophthalmoscope at distance of 50-75 cm, hypermetropes formed a bright crescent inferiorly and myopes superiorly. Formation of crescents in refractive error depended on relative positioning of the illumination and visualization systems of equipment [Figure 1], [Figure 2], [Figure 3]. It was difficult to demonstrate these crescents on retro-illumination with slit lamp as it has perfectly co-axial systems. Hypermetrope displaced bright crescent away from illumination axis towards visualization axis; opposite in case of myopes. As per Kothari MT,[2] the bright crescent is superior in hypermetropes and inferior in myopes with direct ophthalmoscope. But we found opposite results with indirect ophthalmoscope due to exact opposite placements of visualization and illumination systems with respect to each other [Figure 4].{Figure 1}{Figure 2}{Figure 3}{Figure 4}

*Note: All displacements of crescents (right/left) have been described from the examiner's view.

We conclude by saying that refractive errors cannot only be screened by direct ophthalmoscope but also by indirect ophthalmoscope or any other equipment that has adjacent visualization and illumination systems close enough to allow formation of reflex but also at same time having some distance to allow formation of crescents.

Kothari MT has added to the value of the classical Bruckner test as a screening tool for refractive errors using direct ophthalmoscope. We would just like to add that the findings are not rigid to exactly what he described and can vary according to the equipment used. The position of reflex depends as much on relative position of visualization and illumination systems of the instrument used as on refractive status of the eye.

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Conflicts of interest

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