| deafness, sudden | Sensorineural hearing loss which develops over a period of hours or a few days, varying in severity from mild to total. (12 Dec 1998) |
|---|---|
| industrial deafness | Synonym: acoustic trauma deafness. (05 Mar 2000) |
| occupational deafness | Sensorineural hearing loss due to overexposure to high intensity noise levels. Synonym: boilermaker's deafness, industrial deafness, occupational deafness. (05 Mar 2000) |
| organic deafness | Deafness due to a pathologic process or an organic aetiology, as opposed to psychogenic deafness. (05 Mar 2000) |
| functional deafness | Hearing loss without evidence of organic cause or malingering; often follows severe psychic shock. Synonym: functional deafness, hysterical deafness. (05 Mar 2000) |
| low tone deafness | Inability to hear low notes or frequencies. (05 Mar 2000) |
| accommodation, ocular | The dioptric adjustment of the eye (to attain maximal sharpness of retinal imagery for an object of regard) referring to the ability, to the mechanism, or to the process. It is the effecting of refractive changes by changes in the shape of the crystalline lens. Loosely, it refers to ocular adjustments for vision at various distances. (12 Dec 1998) |
| adaptation, ocular | The adjustment of the eye to variations in the intensity of light. Light adaptation is the adjustment of the eye when the light threshold is increased; dark adaptation when the light is greatly reduced. (12 Dec 1998) |
| anterior ocular segment | That portion of the eye comprising the cornea, iris, lens, and their associated chambers and adnexa. (05 Mar 2000) |
| cardinal ocular movements | Eye rotations to the right and left, upward to the right and left, and downward to the right and left, to diagnose positions of gaze. (05 Mar 2000) |
| Ramsden's ocular | An eyepiece of a microscope, consisting of two planoconvex lenses with convexities turned to each other. (05 Mar 2000) |
| vestibular ocular reflex | <clinical sign> Reflex movement of the eyes in the opposite direction to that which the head is moved, e.g., the eyes being lowered as the head is raised, and the reverse (Cantelli's sign); an indication of functional integrity of the brainstem tegmental pathways and cranial nerves involved in eye movement. Synonym: vestibular ocular reflex. (05 Mar 2000) |
| reflex, vestibulo-ocular | A reflex wherein impulses are conveyed from the cupulas of the saemicircular canals and from the otolithic membrane of the saccule and utricle via the vestibular nuclei of the brainstem and the median longitudinal fasciculus to the oculomotor nerve nuclei. It functions to maintain a stable retinal image during head rotation by generating appropriate compensatory eye movements. (12 Dec 1998) |
| refraction, ocular | Refraction of light effected by the media of the eye. It also includes the determination of the refractive state and refractive correction. (12 Dec 1998) |
| goniometre ocular | <microscopy> A special type of ocular fitted with crosslines and a graduated head which rotates the crosslines to facilitate the measuring of angles, as in crystallography. (05 Aug 1998) |