The Bedside Sensory Bench: Acuity, Weber and Rinne
Acuity is the vital sign of the eye, and the pattern of two tuning-fork tests — never either one alone — tells you whether the mechanical half or the neural half of the ear is broken. Set the fork findings and read the diagnosis, record an acuity and see what it means for this patient's life, then sort which sensory tasks you may delegate. Undetected sensory loss is charted as confusion, non-adherence and falls.
512 Hz fork, two tests, one answerWeber puts the fork on the midline vertex or forehead — sound should be heard equally. Rinne compares air conduction at the meatus with bone conduction on the mastoid; normally air conduction lasts about twice as long. Set what you found in this patient.
Weber · fork on the midline
Rinne · LEFT ear
Rinne · RIGHT ear
Whisper screen first: stand about two feet behind the patient, occlude and rub the tragus of the non-tested ear, exhale fully, then whisper a combination of three numbers and letters. Failure to repeat at least three of six items is a positive screen.
Record it exactly as measuredSnellen chart at 20 feet or a handheld near card at 14 inches. Test each eye separately with the other occluded, and let the patient wear their usual glasses or contacts — you want corrected acuity, not a refraction study. 20/40 means this patient sees at 20 feet what a normal eye sees at 40.
Right eye acuity, corrected
If the patient cannot read the largest letter, step down and document which
Counting fingers → hand motion → light perception → no light perception. Then check pupils: swing the light rapidly between eyes, and if the pupil dilates when the light arrives on it, that is a relative afferent pupillary defect — optic nerve or a large area of retina on that side is not conducting. That one finding separates true optic-nerve and retinal disease from cataract, refractive error and functional complaints.
Sensory care has no delegation exceptionUnlicensed assistive personnel may reinforce teaching you have already delivered, position, ambulate, do hygiene, clean glasses and hearing aids, gather supplies and report what they see. They do not assess, do not teach the newly diagnosed, do not evaluate response, and do not take the unstable patient. Decide each task.
What the pattern means
Test
Conductive loss (left)
Sensorineural loss (left)
Weber
Lateralises TO the bad left ear — the blocked ear is shielded from room noise
Lateralises AWAY to the good right ear — the left cochlea cannot transduce
Rinne
Bone conduction greater than air conduction on the left
Air still greater than bone on the left, but both are reduced
Audiometry puts a number on it: 0–25 dB normal, 26–40 mild, 41–55 moderate, 56–70 moderately severe, 71–90 severe, above 90 profound. Tympanometry: type A normal, flat type B means effusion or perforation, type C means negative middle-ear pressure from eustachian tube dysfunction.
What this acuity buys the patient
Delegation scorecard
Drops are medication administration. They belong to the licensed nurse within scope and facility policy, and a licensed practical nurse who gives a drop still reports abnormal findings to the registered nurse. Reinforcing teaching you already delivered is delegable; delivering it the first time is not.