<unk> <unk>  are a diagnostic tool used in ophthalmology, otolaryngology and audiovestibular medicine for the medical evaluation of involuntary eye movement (nystagmus). They are named after<unk> , a German physician.
Frenzel goggles
Windsor glasses
Trifocal lenses
Browline glasses
Adjustable-focus eyeglasses
Argus retinal prosthesis
Pinhole glasses
Corrective lens