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Ears
Published in Marie Lyons, Arvind Singh, Your First ENT Job, 2018
When looking at the eardrum you will see a cone of light. This is the part of the drum that is perpendicular to the light from the auroscope, and its position will change depending on the health of the eardrum. In a healthy drum it lies antero-inferiorly.
P
Published in Anton Sebastian, A Dictionary of the History of Medicine, 2018
Politzer, Adam (1835–1920) Hungarian-born professor of otology at Vienna who gave the first account of otosclerosis in 1895. Politzer cone of light, a luminous triangle on the tymphanic membrane, was described by him in 1889. He also designed the Politzer bag to inflate the middle ear for diagnostic and therapeutic purposes. He wrote Manual of Diseases of the Ear in 1878.
Ernesto
Published in Walter J. Hendelman, Peter Humphreys, Christopher R. Skinner, The Integrated Nervous System, 2017
Walter J. Hendelman, Peter Humphreys, Christopher R. Skinner
Examination with the otoscope shows that the external ear is clear of wax and both eardrums are easily visualized; both have a normal appearance, with a cone of light reflecting in the lower quadrant of the drum. The hearing deficit of the left ear is confirmed using a vibrating tuning fork (at 256 Hz); even Ernesto notes that the sound of the tuning fork is heard longer and better on the right side. The neurologist’s findings are consistent with nerve deafness due to loss of hair cells in the cochlea or a lesion affecting the VIIIth nerve, known as a sensori-neural deficit; this conclusion cannot be considered reliable without a confirmatory audiogram performed by a certified audiologist.
The effect of the ChromaGen contact lens system on visual performance
Published in Clinical and Experimental Optometry, 2020
Cagri Ilhan, Mehmet A Sekeroglu, Sibel Doguizi, Pelin Yilmazbas
There are three types of cone photoreceptors in trichromats that respond best to either small (S cone), medium (M cone), or long (L cone) wavelength light.1972 These cones encode the information for red‐green, and blue‐yellow components of colour vision and luminance. The ganglion cell axons carry encoded information as action potentials. L and M cones mainly project to the parvocellular layers of the lateral geniculate nucleus and this projection is important for red‐green colour vision. A smaller portion of the L and M cones project magnocellular layers of the lateral geniculate nucleus and luminance information is carried by this projection. Ganglion cells which increase their firing rate proportionally with S cone inactivation project to the koniocellular layers of the lateral geniculate nucleus and provide blue‐yellow colour vision.2019 Thus, all three types of cone photoreceptors must serve as appropriate signals for normal colour vision. The loss of function in any type of cone photoreceptor causes congenital colour vision deficiency (CVD). Congenital CVD is seen in eight per cent of males and 0.5 per cent of females.2010 The most common form of congenital CVD is associated with the reduced ability to discriminate red‐green (protan‐deutan defect) and is inherited as X‐linked recessive.2011 It is characterised by the defect in functions of cone photoreceptors, which respond best to either the long or medium wavelength light. Blue‐yellow congenital CVD (tritan defect) is extremely rare and this is characterised by the defect in functions of a cone photoreceptor that responds best to small wavelength light, inherited in autosomal dominant fashion.2014
Bardet-Biedl syndrome-7 (BBS7) shows treatment potential and a cone-rod dystrophy phenotype that recapitulates the non-human primate model
Published in Ophthalmic Genetics, 2021
Tomas S. Aleman, Erin C. O’Neil, Keli O’Connor, Yu You Jiang, Isabella A. Aleman, Jean Bennett, Jessica I. W. Morgan, Brian W. Toussaint
The peripheral visual field extent measured with kinetic perimetry and a V-4e target was moderately constricted in both patients, severely constricted to the smallest size I-4e target. Full-field electroretinograms (ffERGs) showed non-detectable cone-mediated signals whereas rod ERGs were ~80% of the normal amplitudes (Figure 3a). Central retinal function assessed with light- and dark-adapted automatic static perimetry revealed abnormally reduced cone-mediated light-adapted sensitivities by at least one log unit across the central retina, except near fixation where sensitivities approached the lower limit of normal (Figure 3b). Contrasting with the normal retina-wide rod functioning by ffERG, there was also definite rod dysfunction across the central in both patients, locally severe in the nasal retina of P1 where sensitivity losses exceeded 2 log units (Figure 3b). In contrast to this central dysfunction, particularly the cone dysfunction by electroretinography, quantitation of the central retinal structure showed a different picture (Figure 3c). The thicknesses of the central ONL, which includes the photoreceptor nuclei and their laterally displaced axonal projections, and of the ‘outer retinal sublaminae’, a term that corresponds to the distance from the photoreceptor inner segment ellipsoid region (conventionally named inner segment ellipsoid band EZ) to the RPE/BrM were comparatively preserved in both patients (Figure 3c) (57,66,67). At the foveal center the ONL thickness was near the lower limit of normal in P2, thinner than normal in P1. The ONL remained at the lower limit of normal or slightly thinner than normal in both patients, with a local dip between 0.5 and 1 mm of the foveal center (Figure 3c).
Recurrent facial baroparesis on airplane flights relieved by endoscopic sinus surgery: A case report
Published in Acta Oto-Laryngologica Case Reports, 2023
Makiko Toma-Hirano, Ryoji Kagoya, Ken Ito
A 41-year-old man with nasal obstruction and seasonal allergic rhinitis presented to our hospital with right transient facial nerve palsy that only developed during airplane altitude changes. He was taking montelukast and bilastine for allergic rhinitis. He experienced the facial paralysis, once each during altitude ascent and descent in one year. The episodes were preceded by right otalgia and ear fullness, and spontaneously relieved within 15 min after onset. He did not experience other concurrent symptoms including vertigo, dizziness, or contralateral ear symptoms during airplane altitude changes. In addition, the facial nerve palsy occurred when his flight coincided with periods of worsening nasal obstruction due to a viral upper respiratory infection or seasonal allergic rhinitis. On his initial visit, facial nerve palsy was not present. Type B tympanogram of the right side was observed, and the cone of light in the right tympanic membrane was slightly weakened, suggesting Eustachian tube dysfunction and middle ear fluid (Figure 1). Computed tomography (CT) of the temporal bone revealed dehiscence of the tympanic segment of the right facial nerve canal (Figure 2). Based on the episodes over the past year and the findings regarding the tympanogram and the temporal bone CT, he was diagnosed with facial baroparesis. Nasal endoscopy showed nasal polyps reaching the common meatus (Figure 3). Plain CT of the sinus revealed opacification of bilateral maxillary and ethmoid sinuses (Figure 4). Based on these findings, the patient was also diagnosed with CRSwNP. To improve nasal obstruction symptoms and Eustachian tube function, we performed ESS for CRSwNP. Four years after surgery, the patient never experienced facial paralysis during the airplane altitude changes.