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The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain. Damage and death of these nerve cells, or neurons, leads to characteristic features of optic neuropathy. The main symptom is loss of vision, with colors appearing subtly washed out in the affected eye.
Major symptoms are sudden loss of vision (partial or complete), sudden blurred or "foggy" vision, and; pain on movement of the affected eye. [4] [5] [2]Many patients with optic neuritis may lose some of their color vision in the affected eye (especially red), with colors appearing subtly washed out compared to the other eye.
The optic disc is where the axons from the retinal ganglion cells collect into the optic nerve. The optic nerve is the bundle of axons that carry the visual signals from the eye to the brain. This optic nerve must penetrate through the wall of the eye, and the hole to accommodate this is usually 20-30% larger than the nerve diameter.
The optic chiasm, or optic chiasma is the part of the brain where both optic nerves cross. It is located at the bottom of the brain immediately inferior to the hypothalamus. [7] Signs and symptoms associated with optic chiasm lesions are also known as chiasmal syndrome.
An optical attenuator, or fiber optic attenuator, is a device used to reduce the power level of an optical signal, either in free space or in an optical fiber. The basic types of optical attenuators are fixed, step-wise variable, and continuously variable.
o symptoms Zero symptoms ϕ Horizontal orthophoria θ Vertical orthophoria ⊕ Horizontal and vertical orthophoria OC's Optical centres Occ. Occupation OD oculus dexter (right eye) OH Ocular history OMB Oculo motor balance ONH Optic nerve head Oph Ophthalmoscopy OS oculus sinister (left eye) OU oculus uterque (both eyes) PD Pupillary distance
Diabetes, for example, is the leading cause of new cases of blindness in those aged 20–74, with ocular manifestations such as diabetic retinopathy and macular edema affecting up to 80% of those who have had the disease for 15 years or more.
List of medical symptoms. Medical symptoms refer to the manifestations or indications of a disease or condition, perceived and complained about by the patient. [1] [2] Patients observe these symptoms and seek medical advice from healthcare professionals.