For dim reflexes, reduce the working distance from the customary 67 cm down to as low as 10 cm if need be, remembering to take this into account when adjusting the result for the dioptric equivalent of the working distance.

For central lens cataract, dilate the pupil(s) to expose more non-cataractous lens and thereby increase the area of the retinoscopy reflex on view.

For nystagmus, allow the subject to adopt their customary head posture (null point) in order to reduce the amplitude of the eye movements, and refract from the straight-ahead position i.e. off the visual axis.


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